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MG MGB Technical - Ignition problems, could be something else

Hi all,
looking for some advice on a problem that has surfaced recently with my MGBGT (80 reg rubber bumber).
It starts from cold really easily, then runs perfectly well for about 5 or 6 miles, with good acceleration, even running, good oil pressure and temp gauge normal. Then it starts to misfire, gradually losing power and backfiring loudly through the exhaust (sounds like a gun shot) when the accelerator is pressed. This gets so bad I have to stop, so I pull over and have a look to see if I can spot anything amiss. Nothing obvious, so I have a go at starting the engine, it catches and runs, albeit not very well, and I limp home.
This has happened three times now, each new test run preceded by a thorough clean and dry of all the ignition electronics and an examination to see if I can find anything wrong.
I have checked:
Ignition timing
Sparks at plugs with those see through tester things
Resistance of HT leads
Primary and secondary resistance of coil
Oil in SU dampers
Carb piston falling freely
Carb mixture with lifting pins
All of the above are fine and nothing has been altered recently with regards to ignition or carbs.

The logical part of my brain thinks that the current problems may be related to a problem I had last August when an oil pipe split and threw hot oil everywhere under the bonnet. It took a while to get that sorted, partly because I was out of action for a while with a dodgy eye, and partly because the weather was bad. I did eventually replace the oil cooler and pipes, and cleaned everything up as well as I could.

My theory, such as it is, is that either something was damaged during the oil spill or the problem relates to the very low usage of the car over the past 6 months.

Any advice on what to check next? I was wondering about replacing the coil, but I don't want to just start buying parts with no real plan. Also wondering if the head / head gasket may be suspect, just because the problem appears when the engine is warm and not when it is cold.

Other information - when the misfiring happens there is no discernable change at the tachometer, the oil pressure gauge or the temp gauge, and no clouds of smoke from the exhaust as far as I can tell from the driver's seat.

Grateful for any suggestions, and apologies for the length of this post (but then again, you do need all the information I have).

Thanks in advance,

Stephen Elster, Ireland
SJ Elster

Does your car have points and condenser or electronic ignition? The symptoms sound like loss of spark causing unburned fuel to dump into a hot exhaust.

If points and condenser, have you checked the gap and innards to see whether somehow heat is causing the points to fail to open?

I'm no mechanic so these are just WAGS but perhaps a starting point for further investigation.

Jud
J K Chapin

Very wise not to start throwing parts at it.

Yes, sounds like ignition to me as well.

What is the tach doing? If that gets erratic at the same time then it's ignition LT, if not, or if only moves a bit with the backfires, then probably HT.

Getting worse when the throttle is opened sounds like HT breakdown - with more charge in the cylinders the spark finds it harder to jump the plug gap, so the voltage rises, and that will find any weak spots in the insulation. If oil got sprayed around ignition components it could be the cause.
paulh4

It is well worth checking that your fuel tank cap is not blocked. It has a tiny air bleed hole and if it is blocked no air can enter the tank as fuel is used. Eventually the pump can't draw fuel against the negative pressure. This would generally show itself as loss of power and misfiring after a few miles.

Next time it happens nip out of the car and undo the cap. You may hear an inrush of air. Start the engine and see if it now runs OK. Well worth a try.
Mike Howlett

Thanks for quick responses.
I have electronic ignition (optronic) but I could swap in some points and a condenser to see if that makes any difference.
Will definitely try the trick with the fuel cap.
Tach not jumping around. so HT rather than LT. I cleaned up the distributor cap and the HT leads after the oil incident, but maybe these should be replaced to rule them out of the equation - they are probably a couple of years old now anyway.
Also checked the plugs and they all look perfectly normal with a slight light brown deposit - a bit of oil on the threads, but it has been like that ever since I have had the car.

Any point in doing a compression test, or looking at the valve clearances? I don't have a compression tester, but I can get one if necessary. I get the feeling that the consensus is to investigate the ignition before looking further afield?

Regards
Stephen
SJ Elster

Stephen. Run your engine in a dark, but well vented place--at night with an open garage door works well, if available, and look for sparking on the HT wires. Also, look for sparking running down the outside of the spark plug. If you see any you will have an indication of what to replace.

How does the inside of the distributor cap look? Any sign of carbon tracking? Does the center bush show any deterioration? Does it still move upwards slightly? Condition of the rotor? Does it show signs of arching through the plastic to the top of the distributor shaft?

Since the vehicle runs well when cold, problems only developing when the engine warms, there may be a fuel system component. Is the choke off when the problems start? What happens if you give it a little choke (assuming the choke is off)? An excessively lean mixture will, also, cause a backfire because of a build up of unburned fuel in the exhaust system.

Make up a list of things to check. Check them off in a logical order and take notes of anything you find that may be of interest. It may well be the ignition system. But, it could also be something causing the mixture to change, become excessively lean, and showing similar symptoms to an ignition problem.

Les
Les Bengtson

Good idea about fuel cap venting, easy to test, especially in garage, when the car starts to play up leave it running and take the petrol cap off.

HT leads can be faulty even if they test ok off the car on a meter, if you can borrow a know good set it's worth a try. Plus dissy cap can look good but not be so.

Looking for fireworks in the dark does work, and we used to get a mist spray bottle of water to encourage thing but you might have to be wary of the electronic ignition now with that.

One HT lead can be faulty (and even track back at the dissy cap causing all sorts of fun) and not play up until things get warmer.

Another possible is the delicate leads to the electronic igniter head not routed with enough care or
correctly so that they rub inside cap or outside the cap.

Or again a cable/wire/lead that breaks down with heat but resettle when cool.

Also always worth checking all main earths and their connections.
Nigel Atkins

Banging out the back is usually a sign of over rich mixture, and starting really easily cold points that way as well
Which carbuettors does it have---
Another possibility could be the carbon brush in the dist. cap is missing
Dead spark plugs or leads don't usually cause banging out the exhaust, just a missfire under load unless it's caused a track in the cap-
Headgasket blown between 2-3 is also a possibility but if it runs ok for 5-6 klm then I doubt there's an issue there
William Revit

Stephen

Try changing the distributor vacuum advance unit. I had similar problems which took me a long time to get to the bottom off. Turned out to be a very slight pressure leak across the diaphragm so was loosing vacuum under acceleration.

It's a cheap 13 fix and something that has probably never been looked at, let alone checked during the life of the car.

Good Luck

Brian
(1980 mgb roadster)
Brian Davis

It could be the rotor arm breaking down, particularly if it's the type with a rivet through it.
Dave O'Neill 2

Going back into my own past problems:
Check the line between the charcoal canister and the separator near the fuel tank. I had a serious clog in that line a few years ago, which resulted in some of the same symptoms (when everything else seemed to check out).
Just detach from each end, and try to blow air through the line.

Pat
Patrick Callan

Agree with Paul as regards just throwing money at replacements. But we've all (probably) had rotor arms go bad, giving your symptoms.
It's worth swapping that, at least.
And check that your fuel pump can supply, at least a pint in 60seconds.
When things go pear shaped, how hot is the coil getting, but be careful 3 ohm coils??? can get really hot.
Allan Reeling

1980 GT wouldn't have the US pollution controls - I presume.

Agree that riveted rotor arms are the source of frequent failures, ditto carbon contacts falling out of the caps. Distributor Doctor certainly dealt with the former with his red rotors, but that didn't stop every Tom, Dick and Harry jumping on the same bandwagon with parts that were as bad as before.

Coil temperature is proportional to ambient temperature, with ballasted systems being a little cooler than 12v coils. My roadster (12v) and V8 (ballasted) coils are about 40C in an ambient of 8 to 10C which was only warm to the touch. The roadster at 26C got up to 67C with engine compartment at 50C, and the V8 at 30+C got up to 68C with the engine compartment at 64C. The higher temps were too much to keep fingers on, but gave no running problems.
paulh4

I looked through last year's thread (it was actually Oct '19) as I couldn't remember if Stephen's car was a US model for some reason - it's not.

Some info from that thread that Stephen gave that might help with this thread -

' 81(?) reg MGB GT - dont have any US reg polution controls
. 18V 582 engine
. not sure of the vintage of the head
. 45d4 distributor
. optronic electronic ignition
. Carbs are HIF, professionaly reconditioned less than 3 years ago (now 4+ years)

Engine photo from Oct '19 thread before successfully passing Ireland NCT (MOT).



Nigel Atkins

Hi all,
apologies, I have been busy for a few days and didn't get round to updating the post.

A few things have happened:
1. I found a spare 12v coil in the garage, one that I purchased a couple of years ago when I was working out the coil/ballast situation. I did eventually bypass the ballast and used the original (i.e. came with the car) 12v coil that is still there now, so this one was purchased but not used much. I swapped it in and went for a test drive, with almost identical results to the previous few. So fairly confident that the problem is not the coil. When it started running badly I removed the petrol cap, but no whoosh of inrushing air and no impact on the problem. That's 2 possibilities off the list.
2. Ran the car in a dark garage to look for stray sparks. Couldn't see any, but will change the HT leads anyway - when I can get some, which is proving more difficult than previously (local shop not sure if they can get them and Brexit/Covid/Suez Canal seems to be impacting anything imported into Ireland at the moment).
3. Found a spare (used) rotor arm - this was replaced during previous attempts to pass the emissions test, and the car was running fine with it. I am going to give it a thorough clean and see if that makes any difference. Will let you know.
4. Did a compression test, with the following results:
1 152 dry, 162 wet
2 161 dry, 168 wet
3 162 dry, 169 wet
4 153 dry, 159 wet
These are a bit on the low side and also lower than the results from October 2019, which were:
1 158 dry, 172 wet
2 166 dry, 173 wet
3 166 dry, 173 wet
4 155 dry, 162 wet
All tests done with warm engine, wide open throttle and all plugs removed. Any thoughts on these readings? They seem a bit inconclusive to me and I am reluctant to take the head off unless it is necessary.

I will do a fuel pump test - is this just a question of directing the fuel pipe into a bottle and seeing how much comes out in a minute?

I also intend to do a test using points and a condenser to make sure the optronic ignition isn't playing up. I found a set in the garage but they are not in good condition so I need to get new ones before doing this.

Distributor vacuum advance is worth looking at - any thoughts on testing it or is it just a case of replacing it and seeing what that does? I have never replaced it so no idea how old it is.

The coil gets fairly hot, but I don't think it is too hot - I can hold my hand on it and it is uncomfortable but not actually painful.

The distrib cap looks to be in excellent condition, and the carbon brush is present (this was missing from a cap I replaced a couple of year ago, and the engine still ran fine). I know they can look ok and still be suspect, so I will replace it if the other tests/replacements don't come to anything.

I believe the mixture settings are ok, tested them using lifting pins but not with the gastester yet. I haven't entirely ruled out fuel/carb problems though and will keep an open mind.

Thanks for all the responses to date, they are much appreciated.

Stephen Elster
SJ Elster

The compressions don't look bad.

I don't think there's anything to worry about there.
Dave O'Neill 2

Stephen,
(Paul gonna be surprised with me putting this) don't buy new HT leads or other parts just for the sake of it. Certainly replace them if they're old, look poor or fail meter tests (passing meter test doesn't always mean they're actually good in use).

Fuel pump yes just fill a bottle ("what from 'ere?), 30 seconds should be enough but also look at the delivery any coughs, spits, hesitations.

Did you replace that old fuel filter?

If you put the points and condenser back in you could retry the running in a dark garage and using a water spray-mister too to encourage reluctant sparks (you could possibly do this with the electronic but I'm not sure). Carefully, spraying the dissy cap will show if its cracked.

But if you can find that Sun diagnostic machine again with someone who knows how to interpret it that will sort your electric ignition side and what might need replacing if any.

I'm not sure about distributor vacuum, I think I'd try just capping and plugging off alternate and then both ends (I've even got a kit of 4 different sizes sets of cap and plug). I had to fit a larger bore hose to mine, still not sure how much better, if any, it made on mine.

From the previous thread you found the DIY Gunsun type testers aren't that accurate but they might highlight problems at the extreme.

As your problem is when the engine is warm that when you need to do the test and keep the engine warm for all tests as the cause could be very temperature (/environment) dependant.

More than once on here there's been things like, just as an example, wires or their insulation that move and open up with heat (and movement) but then settle again as they cool a bit and/or movement stops.

As with your previous thread, always, always check what you've already doubled checked with the basics before trying to move on.

This subject, runs till warm then stops comes up in different forms many times and the solutions are many and varied with sometimes something that has been thought of as correct because it previously functioned sometimes only failing because of a secondary (or even third, er, ery) minor issue throwing itself into the mix, the straw!

You successfully sorted the two issues last time, this may or may not be related to past issues. Did you have a minor tickover miss before, that might be relevant or just as the car is, these are crude, inexact engines and not Japanese made.

You'll get there, keep going.



Nigel Atkins

I thought I had a similar problem on my TD but it turned out to be a partially clogged fuel filter. The car would start and run fine at first but after a bit enough junk in the filter would get stirred up to cause fuel starvation. A simple matter of just cleaning out the filter fix the problem.

As Nigel preaches - check the simple/cheap things first.

Jud
J K Chapin

Stephen
Just prior to this problem did you have or do any work on the car, if so what was done
Still sounds like going off rich to me from here but--?
have the aircleaners been off-are the gaskets between the cleaners and the carbs located properly with the breather holes free to breathe
What carburetors does your car have HIF-?--they do have an issue with sinking floats
William Revit

Yes fuel pump test is to take the pipe off the front carb i.e. leaving the filter in circuit direct it into a container and switch on. It should deliver a minimum of one Imperial pint in one minute and in practice at least double that rate, in a continuous series of pulses with minimal bubbling. Hesitation or loads of bubbles indicates pump/supply problems or air leaks on the tank side. You can do it pro-rata for a shorter time but as the problem takes a while to develop on th road probably better to go for the full pint.

Carbon string leads are worth replacing with silicone-cored in any event, but check the resistances before fitting as I've known new ones to not have the core trapped under the connector and testing open-circuit, typically 6 to 8k ohms per foot. Don't go mad on price and spec as they are a waste of money, around a tenner should be fine and they go up to several times that.

Willy's gaskets are a good point - some have double breather holes so can't be put on the wrong way round, but you still have to get the filter base plate the right way round - BT, DT! Car ran fine though but failed emissions.

A sunk float would be obvious on a non emissions car from fuel running onto the ground, but if one contains fuel it will be heavier and result in a higher fuel level in the float chamber which could well cause rich running on that carb. Check the plugs before the roughness starts and after it has been doing it a while and compare the front pair to the back pair.
paulh4

Stephen

'Distributor vacuum advance is worth looking at - any thoughts on testing it or is it just a case of replacing it and seeing what that does? I have never replaced it so no idea how old it is'.

Replace it. For £12 (BHive) it's a no brainer. It will be very difficult to test as your only looking at a very small leak in vacuum pressure and that develops over time and running. As I said sometimes the car would run perfectly for up to 50 miles before the symptoms developed.

Apart from when you change the whole distributor I doubt if many people have ever checked or replaced their vacuum advance unit.

I've been through your list of possible problems and suggested solution, (probably 2 or 3 times per suggestion). After about 3 years of checking, replacing, trying, testing, thinking I've solved the problem etc etc the relief in finding the solution well worth the £12 and half hours work to fit.

Regardless of other suggestions try it. You have nothing to lose.

Good luck

Brian
Brian Davis

The (about) £10 HT lead sets might be fine but some of the (about) £20 sets have much better quality terminal boots and overall may offer longer lasting better running quality and overall longevity. Just because something continues to work doesn't mean it's not well past it's optimum, best or reasonable performance and reliability.

I'm all for spending hassle-money if you have it, that's spending to save hassle, at £12 plus P&P it might be worth it as a test but I'd then later look at replacing that unit as I've heard of poor quality vacuum units among the vast array of piss-poor made modern parts.

The bottom part of the dissy is often overlooked and not serviced or repaired, they went out of true within a few years of the cars leaving the factory anyway so imagine how they could be after decades of use, abuse and neglect.

Although thinking about it, I'd pass on the mechanical dissy to those that like that sort of thing and instead install a fit 'n' forget fully electronic (top and bottom) dissy like the 123 or CSI and also enjoy the better reliability and performance, because that's exactly what I did, I even forget now how many years ago about 12 I think. 😊
Nigel Atkins

Dear all,
update on today's activities:
I did a flow test on the fuel pump and it delivered approx. 1.75 pints in a minute, no bubbles and a nice regular pumping noise - so all seems well there.
I swapped the rotor arm for an old one (it was working when I took it out a couple of years ago) and started out on a test drive. I am doing relatively small laps of the lanes around the house so that I won't be to far from home if I need a tow. After the first lap, which is about half way to the usual problem stage, I noticed a steamy smell and pulled into the drive to have a look under the bonnet. There was quite a bit of steam apparently coming from the radiator, along with droplets of water on the rad fins. I let it cool down and gingerly opened the rad cap and discovered no significant loss of coolant, so now I don't know if the water and steam are coming out of a blown rad or are the remnants from my recent cleaning work.
There is definitely some weeping around the switch that controls the electric fan. so I guess that should be replaced in any case. The way the switch fits into a rubber grommet and is held in by a thin metal clip looks like it could never work, but it seems to be the standard issue and has functioned up to now.
Quick hand-check on the block, coil, rad, top and bottom hoses showed all at relatively normal temperature.
So now I am not sure if I have a cooling problem that is causing the running problems, or vice versa, or two separate problems. And I also don't know if swapping the rotor arm has made any difference - the 5 or so miles I drove were perfect, apart from the steam, but that isn't far enough to be able to tell.
I can't buy or order any parts locally, so I am going to have to go to one of the major suppliers and start throwing money at it. I think the next thing may be to test the radiator, but I am not sure how to do that. If I need a new radiator and a complete new set of HT ignition parts it is going to get expensive, but buying online in dribs and drabs makes no sense in terms of delivery costs.
Any thoughts???
Stephen
SJ Elster

Stephen,
I'm not sure 5 miles is enough to tell your problem unless you had the engine fully warmed before starting out. Good idea to do a circular route to keep close to home in the centre.

Let the car cool down fully and check the coolant level in your expansion tank. Hot coolant has a particular smell and I'd have thought you'd notive the needle on the temp gauge wasn't in its usual place.

If you look at the droplets and they're the same colour as your coolant look to see if they get larger going in one direction, small to large from rad might be a rad leak, the other way round could be a water pump leak - but as you say it might be neither just residue water or damp warming up.

See Paul's website for a possible solution to your fan switch leak - http://www.mgb-stuff.org.uk/fansw.htm#4cyljp

I know what you mean about P&P costs and wanting to get everything in one go but it rarely works for me as I forget something or discovered more parts required once work is started - BUT - don't think of ordering anything yet as you might not need to (yet at least). Then you don't have to go to the usual suppliers always especially for single bits where the P&P is proportionally high. Some (smaller for us) suppliers very annoyingly sell the item on ebay with 'Free P&P' but charge P&P if you order direct from their website. Plus not so much so with the B but Mini spares suppliers often work on lower overheads so offer the same item for less and sometimes offer better quality items than the 'usual suppliers'.

Do the clip trick on fan switch, check everything in engine bay, then wash off any fluids. Fully warm the engine at home and check for leaks before going on your test laps again. If your worried take with your some suitable premixed coolant and keep an eye on the temp gauge. Report back.
Nigel Atkins

Ha! Any droplets of water from the cooling system getting near HT components are likely to cause a misfire. That was the only indication I had with a punctured hose on the V8 many years ago.
paulh4

Leaking heater valve(?).

One of the reasons I use 4-Life is that it shows up leaks so well, hot and cold, and forensics spray pattern diagnosis, magnifying glass to eye!
Nigel Atkins

I'd just go round the block again and try to reproduce the engine missfire, then get out and have a looksee at the radiator etc to see if you have a leak spraying around or if it was just residual water from your previous cleaning efforts
No use jumping in buying stuff till you find the cause
willy
William Revit

Stephen. The radiator is checked by filling it up to the proper level, then attaching a radiator pressure checker (a pump with a gauge on it with a hose running to a fitting, similar to a pressure cap). The fitting at the end hose is attached to the filler neck of the radiator or expansion type, depending on year. The system is pressurized using the hand pump and you note whether the pressure holds steady or drops. If it drops, it indicates a leak somewhere, often one which can be observed by the coolant being forced out of a hose or joint. The same instrument is used to test the radiator pressure cap for its ability to hold its rated pressure. Any good garage or mechanic should have one of these test systems and should perform the tests for a nominal fee.

Les
Les Bengtson

The bit that doesn't check is the seal between the cap and the radiator even when the cap is fitted to the top of the pressure test adapter. I've made an adapter that's inserted in series with one of the heater hoses on cars with the earlier radiator, and with the expansion tank hose on the latter, as I have one of each. The additional benefit of those is that I can check the pressure hot under real-world i.e. driving conditions, by connecting a gauge in the cabin in place of the pump.
paulh4

What Les and Willy won't know is that the garages and mechanics in the UK, well my area at least, seem to vary a bit to theirs. A couple of years ago I asked around about one of those testers to test a pressure cap (to prove a well known and respected supplier wrong) but no joy in finding a tester. I do know the breakdown vans have them (DAMHIK).

I have to smile when Willy or someone from the US puts nip here or there and get this or that done, and for a nominal fee, unless you know someone in the trade tracking these people down and getting anything done below a minimum fee and within a certain time is often very difficult. They do exist but not readily to your 'average Joe', and I'm someone with great charm and great good looks, and modesty.

Perhaps it's different in Ireland though.
Nigel Atkins

Good point about the garages, and if anything it is worse in Ireland. A few years ago there were several garages in the local village with mechanics that would do work like that now all either closed down or just selling petrol and breakfast rolls. Several miles to a larger town where there are a few garages that sell tyres and exhausts, some of these do mechanical work too but dont want to take on an older car. So basically I am on my own and l am learning to be self sufficient. Obviously with a lot of hrlp from you guys:)
SJ Elster

It's annoying just how many useful 'bits' that seem to be commonplace in America (at least) are not available here, and only available from America at a huge cost in post and packing. Even some (at least) Farnell UK electronic components are 'fulfilled' from America which quadruples the price of small components and connectors.

My son posted two sun visors to California for repair which got there in two days for about £6 with a choice of half a dozen different carriers. Coming back it seem to be American Postal Service or nothing at huge cost and a long wait.
paulh4

I'm starting to understand Nigel----

Don't understand the comment about the tester not testing the seal, that's one of the things that a pressure tester does
The testers we have here are a pump that just screws onto the filler instead of the cap and you just pump it up, then there's a double ended fitting that will take the tester on one end and resembles a filler neck on the other, where you can screw your cap on and test the blowoff pressure of the cap and test that the seal will hold pressure.
It's quite common to have a faulty cap that blows off at the correct pressure if you pump it up but won't hold pressure because the rubber seal has worn or it's got rubbish jammed in the return valve

willy
William Revit

Dear all, today's update is that I dried everything under the bonnet by abusing a hairdryer, and then I made up a DIY pressure tester using a bike pump with a pressure gauge and the valve from an inner tube. The valve is a good fit into the pipe that connects the rad with the overflow tank. I pumped it up to approx 15 lbs/sq in and it held the pressure really well, actually much better than I would have thought (bearing in mind that I havent done this before) - as well as the gauge holding steady, I couldn't see any liquid coming out, nor hear any hissing noises. This gave me confidence to try another test drive, but before starting the engine I measured the level of coolant as accurately as I could with a small piece of wood as a dip stick.

I did the usual length test drive, and no mis-firing this time, oil pressure and temp gauge normal, so looking promising.

After everything had cooled down I had a look under the bonnet to discover a bit more wetness around the top of the radiator, and a small drip from the top hose to radiator connection. I measured the coolant level again and it was, as near as I can tell, identical to the previous measurement. This is a bit contradictory, because some coolant has obviously been lost and yet the same amount remains, and I think that contradicts several of the laws of physics.

I tightened up the clamp on the leaking joint, and will try another, slightly longer test drive tomorrow.

Not sure if I am out of the woods yet, but definitely making progress. I did also have a good look at the radiator, and it really isn't in pristine condition, with several bent fins and quite a bit of white/green corrosion, so it is going to have to be replaced at some point. I found one at a reasonable price on Midland Sports and Classics' web site, but it is collection only due to the fragile nature of the item, so that might have to wait until I make my next trip to England, which will itself have to wait until travel restrictions are eased. Another possibility is to see if anyone local will do a re-core on the existing rad, but that would probably end up more expensive than buying a new one. And there remains the issue we discussed earlier about the diminishing number of places that will do work like that, but there is a place not too far away that I will contact to see if they are interested.

Will let you know how the next test drive goes - at least this is all giving me plenty of driving time.

Stephen
SJ Elster

Stephen

Where in Ireland are you? I do three or four trips a year, to various parts.
Dave O'Neill 2

I live near Stradbally in County Laois - Portlaoise is the nearest town of any size.
SJ Elster

I’m often on the M7 from Dublin to either Cork or Limerick, so if you needed anything bringing over, I’d be happy to help.
Dave O'Neill 2

Very kind offer, Dave, thanks, and I will take you up on that at some point. Some good meeting points near junction 17 with easy parking and coffee,
Stephen
SJ Elster

Well done Stephen.

I did think about suggesting making your own test kit but like the garage and mechanic bits not everyone has a pushbike or pump or old inner tubes lying around.

I think pressure tests are normally to twice times (?) but if your system is working at cap pressure (and the cap is working) then that's OK and going twice times might be the straw.

Only recently I bought for the shed a £13 TRESemme 1800w "two heat/speed settings plus cool" which I've used to warm up bullet sleeves to remove and replace and blow out - hence the cool setting - well, so far only dust from the rads in home but I did want that setting for some thing on the car but can't remember what. This supplements the 630w small folding hairdryer my wife gave which is handy for size but not man enough for winter use.

Tiny drops of oil and coolant can look massive so seeing no drop in coolant level is no surprise.

In another thread I put about a jubilee hose clip on my rad that seemed tight and to nip up but when I took it off it was ovaled so needed replacing and I had used the correct tighten technique which is to slightly loosen the clip before tightening or nipping up - so consider that about yours.

Hold off about replacing the rad as it might not be as bad as you think, a replacement could soon have some bent fins (or arrive with some) and condensation (often from lack of sufficient use of the vehicle) can soon build on a new rad.

It's more about the internal condition of the rad for your cooling - but you've made no mention of having any cooling problem.

Carefully brush debris out of the front and rear fins of the rad, then you can carefully wash clean the rad front and rear and see what it look like.

I have very thorough (very simple and basic) cooling/heating system cleaning methods notes that are (not) world famous and often considered OTT and very much under appreciated but I think three people have said they used them and found them helpful, you're welcome to look a and ignore or partly do when the weather is warmer and cold wet hosing is better appreciated, just email me.
Nigel Atkins

Stephen,
I forgot to put I doubt a small coolant leak from the top hose rad would cause the misfire but I could be wrong, I think more likely, if resolved it's because of something you done before the last test drive.

Just blow drying might have helped but all your electric for the ignition should be sufficiently ordinarily sealed to resist a fair amount of water and condensation, remember the custom cars with fully exposed petrol engines.

Damp/condensation/water inside the dissy or cracked or exposures of insulation on cables, leads and boots is another matter.

Go on another of your circular test routes and if everything is still good then carry on for at least another 25 miles, or better still more, on a better test run and find roads were you can appropriately give the car a good blow-out, proper Italian tune-up, sustained high revs, 3rd gear if required, it'll do it the power of good.

Provided the car doesn't remain too static too long after this run then on the next run, make it 30miles plus, the car may well go better.
Nigel Atkins

Try swapping the rotor arm back and see if the misfire returns.
Dave O'Neill 2

Nice one Stephen, I hope that you've found it with the rotor button.
I'm bitterly disappointed that it wasn't a float half sunk --LOL but i guess having recently rebuilt carbs they would have had them replaced at that time anyway-
Which brings up a point-
Chasing around looking for issues it's 'always' a good idea to only change one component at a time otherwise you'll never know what the real cause was
Checking is ok but actual parts swapping--one at a time
If it's ok now, Dave's idea of refitting the old rotor to prove the fault lays there, is a good one for your own peace of mind
On the pressure testing subject, I'm always wary of not going much over the cap rating pressure, as in if the cap is 10 lb(for example) i'd go 12 at the most, i've seen plenty of heater cores and radiator tanks wrecked by over pressuring. The system is never going to exceed the blow off rating of the cap in service
Being an 80 model and doing it as you have the cap wasn't in the circuit but you could test that separately by fitting your pump to that same hose back the other way towards the expansion tank to see if the cap is blowing off at the correct pressure and holding pressure at that
William Revit

"Try swapping the rotor arm back and see if the misfire returns."

A man after my own heart. If you haven't proved the component you have changed really is faulty, you can't have full confidence that it was the cause of the problem.
paulh4

Stephen could put a photo of the rotor arm and if it's the type with a rivet through it we can take it as a modern made piss-poor part if it wasn't playing up before it probably will in the near future.

IF Stephen's car is sorted now then the old rotor can be tested by Dave or Paul putting it into their MGB and going for a run with it, are either volunteering to do this? 😜

I don't disagree with finding out what the actal cause is - BUT - also it depends on levels of priorities and why you bought the car in the first place. IF the car is now running correctly then I feel you have to be very careful about the farting-about to driving-and-enjoying ratio.

To some the farting-about is enjoyment of tinkering and discovering, a good excuse to (partly?) have the car as a mechanical play thing, which is fine, and not to drive it which is the less enjoyable part to tinkering.

Yes the parts should be tested and swapped out one piece at a time but if that also involves a test run every time then the car, at that time, becomes more about tinkering and test drives than actually driving the car for enjoyment.

If the car is now sorted then to retrospectively take off parts and do individual test runs could become very involved if it's not the rotor arm at fault then how far back do you go. What if it's a combination of parts and circumstances.

If it is the rotor arm, which is very possible based on the number of piss-poor quality rotors the suppliers sell, then do you trust the rotor that's now installed for reliability, do you trust the copy "red rotor arm" that many sell or go to the original Distributor Doctor 'RED ROTOR ARMS'. - http://www.distributordoctor.com/red-rotor-arms.html

Stephen is in the minority of classic car owners that don't mind spending money on function parts but as we know the majority insist on buying cheap very low priced and low quality service and repair parts with many, MGB owners particularly, very happy to spend money on bling parts that are all about show and not go.

If anyone has an interest in testing poor quality parts just buy modern made parts from the suppliers that they still sell because tight-fisted classic car owners insist they sell them, such as rotor arms. 😁
Nigel Atkins

Nigel

Much as I would like to help with testing the rotor arm, it won't fit my 123 distributor. It wouldn't have fitted my original 25D4, either.

It was my car, I would want to be as sure as possible that I had found the cause of the intermittent fault, so that I would feel more confident that it wasn't going to return.
Dave O'Neill 2

Dave,
I did think about the different dissys but details should never spoil a wind-up.

You have surprised me alittle that you've got a modern fully electronic, top and bottom, dissy though as that totally rules out any 'fun' of adjustment (and with different rotor and cap).

I agree with you about having confidence in having sorted the problem but as I put Stephen's already done things and changes in groups so to go back to individual part changes or actions now could be very time consuming.

And some people, and not JUST me, have a threshold of how much hassle and farting about with cars that they can put up with in one go and need rests and rewards from it like actually driving the cars, they have tyres and wheels for that reason, especially after potentially months of not being able to do so (altho' I've no idea about Covid restrictions in Ireland, bad enough keeping up to date with just here).

I did think about putting that Stephen should change back to the previous rotor before his next run and take along with him the present rotor to swap out if required but he'd probably not then feel confident enough that to do other than the circular short test route which wouldn't put the starting charge back into the battery or fully warm the whole car and be yet another test run. Then what if the previous rotor arm is fine, how many more test runs?

I did put 'IF' the car is sorted, and if it is why not have a short time at least of enjoyment of proper runs in it.

When doing a service of the car generally items of service are done at the same time, we don't just change the oil and oil filter and go for a comparative test run to check the level of improvement for just that or replace one spark plug at a time and test runs after each.

Much better I thought that yourself or Paul test the rotor arm, I'm sure my mate will have an old 45d somewhere for you or Paul to use to test this rotor, I can ask if you like?

Or if Stephen puts up a photo of the previous rotor and it's the tight-fisted owners' piss-poor modern made cheap type I'd suggest to Stephen IF his car seems sorted, regarding this issue anyway, then he keeps driving it as such, as the issue was so pronounced previously he's going to be looking out for even its slightest return and if the rotor was the sole cause then he's sorted.

Now you must come to Northampton way with your work, and I'm used to going Solihull way, so should I ask my mate to look out a 45d?




😜
Nigel Atkins

Hello again. I seem to have sparked off quite a discussion, apologies for the HT pun.
I had another drive today, 15 miles without any problems. Still not long enough to say for sure, but I will do a longer one next week when lockdown gets relaxed - we are supposed to stay within 5km of home at the moment unless travelling for essential reasons.
I will put the old rotor back in when I am a bit more confident that the problem has been solved, but it might not be definitive because I have also tightened up a leaking hose clip, dried everything under the bonnet and cleaned all the electrical connectors I can get to.
Posting a picture of the suspect rotor as suggested. It does have a rivet, but it is a long way from the centre.
While looking at the cooling system and checking for leaks, I have seen coolant around the fan swictch, as mentioned previously. The coolant that I think is coming from here is collecting in the top ridge of the radiator, and I will have to fix that before I can get confidence back in the car. I will attach a picture of this too but it might not be very clear. I guess the only part that needs replacing is the rubber seal - is that a generic seal that I might be able to get locally or will it have to come from one of the usual suppliers? Also, is it worth trying to fix it with any kind of gasket sealant or is that just a waste of time?






SJ Elster

Nothing wrong with a discussion or difference of views and Dave and Paul would gladly help you where they can.

The issue of piss-poor modern made rotor arms goes back 20 years of failures and isn't just the rivet but also material mix, see: - http://www.distributordoctor.com/rotor_arms.html

IF it does turn out to be that rotor (or even if not I'd change it) keep it on the dash, or by the phone, or with your records for the B as a reminder of piss-poor parts potential and the hassle they can cause.

I've no idea if the seal is a standard size available elsewhere, others might know. ALWAYS, always consider that many modern made rubber parts from the usual suppliers have been of piss-poor rubbish rubber, I don't know with this part, it might be fine if it's also used outside of classic car parts or supplier by non-cheapest-possible manufacture.

Again others might have better ideas or know if I'm suggesting anything wrong with anything that follows.

It might be worth trying to remove the switch then seal, carefully cleaning the aperture in the rad to remove any crud to get a better, er, seal with it. Then clean the seal with whatever you've got to clean and improve rubber, I often use Autoglym Bumper and Trim Gel, or silicone or PTFE.

If the seal is split you might even be able to glue with appropriate adhesive.

If required to get a better fit/seal my go to with coolant seals or gaskets is Hylomar Hylotite Red 100, never let me down where the Universal Blue has. I don't know if it's suitable for use against rubber seals so you'd have to check with the manufacturer. - https://hylomar.com/en/hylotyte-red-100/

Or you could perhaps try a brushing on a smear of silicone grease on the seal inside and out, not too much that it might squash into the rad and be a jelly clot(?). Or carefully wrap the seal and switch with the (thinner) plumbers PTFE tape to gap fill and perhaps make the seating of seal and switch sturdier.

In a perfect world I wouldn't fart about and just replace that seal - and I wouldn't have ever needed to use the Red 100 on other gaskets that should be able to be fitted dry but this is the world of imperfect classics and often very imperfect modern parts.

Stephen don't let me dishearten you, these cars are very simple things and in most instances you can even put up with continuing to use the car piss-poor modern made parts without the world or car falling apart.

Fortunately, and unfortunately, the way to get the car more reliable and your confidence in it is to go for regular reasonable distance runs all year round, and occasionally, or more often if you like, give them a bloody good blow-out. Classics don't all have to be unreliable, poor handling and slow as often it's the owners that make and keep them that way by not driving them regularly enough to know how well they could and should go, which includes firstly braking then, steering, handling and road holding. Things like speed, power, engine and carb fiddling are bottom of list.






Nigel Atkins

Stephen
You shouldn't need to goo up the sensor seal, the rubber ring has probably gone hard/shrunk from heat
A new 'O' ring seal will fix it--
Beware though there are two types, yours, going by your pic is the later one-they're cheap, only a couple of dollars-

Part number--------- 542-203--BUSH

OR B&G have got them under their number--
SEAL FAN SWITCH MGB

Product Code: KTP9005

Fitted from CH No.511520 onwards

William Revit

That style of rotor should be fine - or at least not suffer from the rivet problem as it is a long way from the shaft as you say. Image 1 tend to be the problem one as the shank of the rivet is so close to the shaft when fitted.

Originals, and Dist Doc's red rotors are bonded and not rivetted. There are others like image 2 that are riveted further out but may still have a problem.





paulh4

Stephen,

Willy is correct about the seal being part number KTP9005 with the switch being KTP9003.
There is a spring clip that holds both in place.
I seem to recall that John Twist suggested using two cable ties threaded through the radiator fins to help hold the switch firmly in place as some have found the switch tends to be forced out.
See attached photo of seal which is stepped.

Cheers,

Charles


Charles9

As mine was a long thread just to summarize it.

Stephen's rotor is similar to Paul's Image 2 but it's not just the rivet that cause the problem on poor quality rotors, and it looks like Stephen sourced Paul's website info on the rotors (rivet) issue.

For the switch seal I put in a perfect world I wouldn't fart about and just replace that seal but I've no idea if the seals that are stocked are good quality or modern piss-poor rubbish rubber. Has anyone fitted one recently?

To have the car running without the worry of it split leaking I'd inspect the present one and clean up the area and clean and try to condition the seal or whatever else is required.

Personally for the cost I'd risk ordering a new seal when ordering other stuff but I wouldn't throw the existing seal away in case the new seal was piss-poor quality.
Nigel Atkins

Willy,
I meant to put, another possible difference between here and where you are could be parts quality and particularly any parts with rubber.

I rarely mention it but although I normally keep it to myself we do suffered over here from owners insisting on lowest prices for parts so we get lots of piss-poor parts here particularly rubbish rubber.

For the cost the suppliers get the parts they should be more honest and send out at least 2 or 3, or 5 or 6, or 10 or 12 when you by the part, to give the retailer purchaser a chance of finding one among those sent that actually fits correctly or works fully, and then perhaps a second that will do the same to double the usable life of the part even if it's static and unused. Some parts only last minutes or hours or days. If you're lucky PITA to fit parts might last weeks or months but always with the thrill of never know when they'll start playing up or cease functioning.

Although I was often told, as were/are others, that I'm the first to report a problem I know I'm not alone because a few others will post with the same problems with piss-poor modern parts quality - and it doesn't and won't stop with the insistence of tight-fisted classic vehicle owners as the practice has got quite widespread. I've just had to replace, after less than 5 years use, a very expensive bit of plastic and minor electronic apparatus (well designed and formerly well made in the next county to me) because spare parts and specifically electronics are not available at all as the corporation that bought out the original company has the whole thing made in China with no parts availability. Straight out of the box I can feel the new one has inferior external plastic, I've yet to look at the mechanism and electronics - but it does have a 3 year manufacturers warranty, which would presumably get me only a complete new replacement unit.

Bit ironic with the promotion of recycling and the supposed upcoming legislation to get manufacturers to make parts available for repairs.

All these countries putting all their eggs into one basket (and some sending their coal there!). 😊

It's all great stuff, yer gotta laff. 😂
Nigel Atkins

Agreed, China is a big issue here at the moment,I think the Federal Gvt. has seen the light with your too many eggs in the one basket.
To me they(C) look like they've got their nickers in a knot about something and are banning or sticking large taxes on Aust exports-----including coal, food, wine
Their exports to here are as you describe there, cheap and nasty--but in saying that, some stuff is really good, it just depends if there is someone there keeping the pressure on quality control
I've heard that steel quality is an issue where they'll produce something to spec but once production starts it just goes downhill unless someone from outside is monitoring it
My VW Golf keeps killing it's electric boot catch
The VW one is $280 which i've replaced twice with genuine VW and only just lasts long enough to get out of the 2 year parts warranty--About 4 years ago I thought bugger it and bought a China replacement $23 with free postage, it looked identical to the vw one and has been faultless since
Now i've put the mockers on it ,it'll probably die tomorrow--I'm going to blame you if it does Nigel
Cheers
willy
William Revit

The problem with my Golf has been horrendous condensation, sometimes like someone had put a garden hose through an open window. Then I noticed water sitting on top of the rear door seals, and with the trim panels off it was coming past the speakers where they are riveted to the doors, with the plastic speaker flanges badly cracked. Googling showed loads of complaints about condensation, and these speakers 'leaking'. One speaker was too badly broken to refit but a dealer replacement was 'only' £40 so not too bad. The other one wasn't so badly damaged and worth trying to seal a different way, still get a little bit from that side. Poor original design.
paulh4

Interesting Paul. My wife's Touran, which is based on the Golf, also suffers with condensation. I wonder if it's the same problem? Must investigate.
Mike Howlett

What! German engineering not as good as it's cracked up to be, what a surprise! 😃

German car owners usual keep this to themselves to perpetuate the myth and keep up the resale price for when they pass the problems on.
Nigel Atkins

Willy,
I've put before about a mate, a few years back now, who very, very reluctantly had to have some production from China after resisting for as long as he could. He said if you kept someone of your own over there or kept checking on quality very regularly things could be good. Even though he got stock from China that needed sorting out in his factory in England by his staff it was still cheaper to do this than have it made in England because of material and wage costs and the contract selling price.

Aus sending coal to China is dancing with them and then moaning because they pick the tune, and Aus are polluting on their own doorstep (if you know the saying, if not I can spell it out) - and everyone else's door step.

Nigel Atkins

Foggy VW
I spent part of my life working at a multi brand new car dealership--During winter it was VW that had a condensation problem more than the others.
I think it is mostly caused by them being more sealed up(airtight) than others--Obviously if there's a water leak it needs fixing, the door speakers here have a plastic cover over the rear of them that acts like an umbrella, don't know why you have a leak there, but
The fix for a car with condensation but no water leaks is get an old sock and fill him up with kitty litter and throw him under the seat--no more condensation
Nigel
Now that we've taken over Steve's thread,
The story with Australian coal to China isn't how you see it-
The coal they get from here is the cleanest burning highest energy output coal you can get
China has heaps of coal of it's own and they buy coal from elsewhere as well, but the game they are playing is all about screwing the price down to the same price as the crap coal they otherwise have to use--Their pollution output is sky high and they need Aust. coal to reduce that--they're just playing bullsh*t games---If Australia cut their coal supply you wouldn't be able to breath over there

As far as Aust. polluting at home, that's a bit rough
About 100klm West of me here at Cape Grim there's a weather station which constantly rates as the cleanest air in the world-It's used as the baseline for measuring worldwide air quality--yes I said worldwide
Overall Australian pollution is quite low but the figures are produced on a per head of population basis--Australia's population is quite small compared to many countries with the total pop. being probably less than one city in Chi.
Population wise the whole country here is about the size of two Lunduns---If you can imagine all of Australia's industry based in the middle of Lon. there has to be some emissions
William Revit

Mike - mentioned on the MGOC forum and someone else plagued with the same condensation found the same cause. Just pour a watering can full or hose back and fore across the glass, then when it stops dripping ion the outside open the door and look on top of the seal, image 1.

Silica gel packs made very little difference.

"not as good as it's cracked up to be"

Ho ho, these are well cracked up.

The speakers have a foam seal round the flange, but both mine and several on eBay have breaks that can let water past. If the flange cracks as both of mine did and again others on eBay it gets past a good seal. Image 2 is the better of the two speakers by far.

There are waterproof foam 'speaker baffles' that look like they should keep water away from the back of the speaker, but only in America that I've been able to find with typical extortionate postage at more than the cost of the item. I did similar with stout poly sealed all round the edge to the door with duct tape, and on the back for the rivets with non-hardening sealant.






paulh4

Willy,
it's very simple, there are two parties to the deal, if they lower the price then stop dealing with them and sell it elsewhere. What part of the deal allows them to lower the price. Did Aus go into the deal feeling it was the senior party, if not then they must have known they were open to power plays with them being the weaker or was that against the national male attitude, same with USA feeling they have the upper hand, based on very outdated attitudes and beliefs. Aus and USA have known for decades the growing power of China it's a matter of when they accept(ed) China as the greater power and treated with them with caution rather than thinking they can be controlled by lesser powers.

I'm not certain Aus sold coal to China just for the good of China and the rest of the world.

Each country exports its air pollution to others so local measurements are only part of the story.

But - I'm with you, I'm keen to known how Stephen gets on. 😊
Nigel Atkins

Nigel
I'm not going to get into a China debate here but you've got it wrong, and I see you think Aust .is in bed with USA--brainwashed, that's exactly what Ch. wants the world to think and in the meantime they're out in the ocean not far north of Aust building military bases on atolls and banning any shipping from going anywhere near
there is a wave of fresh young politicians in China thumping their chests and trying to make a mark--- and they just do what they want basically
I've got no issue with China being a powerfull nation no more than a don't have an issue with say UK being a powerfull nation, but I do have an issue with a country like China that thinks it can do whatever it wants anywhere it wants
They've got plenty they could be doing to improve the lives of their own people but they don't seem to matter------
William Revit

And making their own atolls in open seas on which to build them, and create additional territorial waters with which to exclude nation states nearby.

I don't consider the UK 'powerful' on the world stage now, and when we were "thinks it can do whatever it wants anywhere it wants" probably also applied. America is doing it now, Australia sells millions of tons of coal to Asia and even the UK, all three of us 'because we can', as is China in doing what it does.

Someone on a TV rail journey across Australia stopped off at a huge coal mine. It may have been my imagination but even the manager of that looked a bit sheepish when he said how much they exported.
paulh4

Yeah, I agree but the difference is everyone is trading for business or out of necessity but Ch. has an agenda, they've even got a name for it called The Belt and Road ,but noone except them knows what that is--

https://www.forbes.com/sites/wadeshepard/2020/02/28/how-beijing-is-losing-support-for-its-belt-and-road-initiative/?sh=fee508321990
William Revit

Two very quick points, I don't think Aus is brainwashed by USA I only put the two as both have done huge amounts of trade with China and now whinge about it and China having the upper hand when they thought it'd be the other way round. And I realise what China is up to as it's what USA consumer/capitalism/religion and some of those from the Arab world does and Britain done a good while back.

And as Paul has put the UK isn't powerful, particularly now we're a 'proud independent' er, devolved nation, set of desperate islands, landmass, empire(?).


Nigel Atkins

No no no--Australia and China have signed a free trade deal ,They can sell their stuff here without extra price loading just straight out GST the same as everyone else, which has killed a lot of businesses here but made most more competitive, but when our stuff goes over there they reckon we're dumping on their market and ban stuff or put huge tarrifs on because they reckon our gov. is supporting the exports, wheat for example or wine-
And yet almost all their exports into here are from gvt. owned and run factories etc--go figure
I could go on about this forever but I'm stopping now, right here ----------------------------------------------
not fair to Steve's thread

William Revit

Getting slightly back on track, regarding radiators...

Although Midland Sports & Classics website says 'collection only', they seem quite happy to ship their ebay sales:-

https://www.ebay.co.uk/itm/183009100065
Dave O'Neill 2

I bought a new radiator, not for a MGB or from MSC, but if they use the same supplier or manufacturer then I'd recommend you don't bother, quality isn't good.

I wished I'd risked one the cheap ali ones that ones seem to have found good, even if it meant bling that'd be very out of place on my car.
Nigel Atkins

Willy,
if you go to meet someone and they start kicking you in the testicles then stop going to meet them - even if you're wedded to them commercially. Make 'em suffer, stop providing them with that fabulous clean coal, show 'em oo's boss. 😉
Nigel Atkins

'Belt' - the one they put round your neck.

'Road' - the one that lay over your bones.
paulh4

Slightly off topic, ie not relating to the geopolitical issues in the Asia-Pacific region😁, I think I need to solve the wet radiator problem before doing anything else. To which end, I have ordered a new fan switch seal and clip, and while I was doing that I couldnt resist getting a good Dist Doc red rotor arm too. When those parts arrive I will install them and see what things are like at that stage. I suspect I might still need a new radiator, but hoping the new seal will suffice. I will be able to tell fairly quickly, the rim around the top of the rad will either be wet or stay dry after a test run. If it is wet, then further investigation will be necessary.
I have found a local place that will test my radiator and repair it if is repairable, but they wont quote a price until they have done the test - I think they are likely to charge more than the cost of a new rad, but it might be the better option. Having said that, I have no idea whether the rad I have now is original or a poorer quality replacement, is there any way to tell them apart?
SJ Elster

I had my radiator recored last year. It cost more than a replacement, but I know it was done properly - and locally - and had a boss for a modern fan switch fitted at the same time.
Dave O'Neill 2

I suppose we could address this thread drift to car matters (bit of a cheek tho').

Dissy Doc red rotor arms have DD on them, so if it don't it's a copy, that's not to say its bad just possibly not as good. The 'red rotor arms' I've got from the likes of Powerspark and Accuspark both look to me to be identical and no doubt work as I've tested them but they do look a bit "light duty" and not concours finished compared to the Bosch and Beru equivalent versions for my fully electronic dissy.

Clean the rad up around where the new seal is to be installed to get the best seal to rad. Keep the existing seal and clip until you know for sure the replacements are better. I've often made the mistake of throwing the old part away to find the new part to fail or not be as good as the old part - but don't keep junk be it the old or new parts.

For the rad have look at Paul's site but the rad doesn't have to be original to be good, the place that tests your rad should be able to tell you if it's well made or not. If you have to take the rad out then that's a perfect opportunity to clean and sort as much of the cooling/heating as you feel you want to.

http://www.mgb-stuff.org.uk/coolingtext.htm#rad
Nigel Atkins

Stephen, (or anyone on the E10 list),
BTW, I keep forgetting to say, after the October '19 thread where I suggested fuel additives to you and worked out one was at most 6p per litre extra cost I asked my wife how much extra I paid for Shell V-Power and Tesco Momentum 99 which I bought mainly for their cleaning additive packages. My wife said it was 10-12p extra over their 95 standard petrol (I never bother with the fuel costs as I use so little in my midget now).

So I tried a 50 litre bottle that would treat 500 litres of petrol, I'm still on that first bottle for various reasons, Covid situation being one.

I must say I'm pleased with the results of how it makes the car run compared to using the higher octane and more expensive fuels. I don't get my knickers in a twist over ethanol but when the E10 comes in over here I'm covered anyway with the additive and would be for unleaded petrol too but I don't need that protection either as I bought the car with unleaded head.

To remind you (and better running can mean a bit less cooling required) -

Millers VSPe Power Plus Multi Shot Fuel Treatment - 500ml

"An all in one, multi shot, petrol fuel treatment providing ethanol protection, lead replacement and an octane improver dependent on selected fuel quality. Recommended for all classic engines previously requiring leaded fuel and now running on unleaded fuel. Endorsed by the FBHVC.
USER BENEFITS:
Endorsed by the FBHVC as a fuel treatment for protection against corrosion in metals
Octane enhancement of up to 2 octane numbers (20 points) dependent on fuel quality
Prevents valve seat recession when used with unhardened valve seats
Prevents detonation, hot spots & running on
Prevents fuel system corrosion and helps protect components
Combats the adverse effects of ethanol in fuel (up to E10)
Carburettor anti-icing formula
Contains anti oxidant to improve fuel life"

https://www.millersoils-shop.co.uk/vspe-power-plus-multishot

PDF attached.



Nigel Atkins

From what you say it seems unlikely that you would have used 50 litres of fuel in recent times, let alone 50 litres of additive. Is there an additive to stop the additive going off :o)

Just like unleaded and E5 when they first appeared there is a lot of nonsense talked about the effects of the changes. America has been using ethanol for longer than us and at higher concentrations, plus other witch's brews, and there are no abject wails about the effects of those even when specifically asked.

I used Castrol Valvemaster until recently merely as cheap insurance against valve seat recession, I tried the boosted version but found it made no difference to pinking on my roadster which has always been prone even on leaded. I've always used the higher octanes on that anyway and will continue to do so. For the V8 which has always run on supermarket 95 I'll change to the higher octanes when E10 appears at the pump - during this summer, BTW.
paulh4

Yes I've had the bottle some time now and you've reminded me that I think there was something that previously prompted me that I should remove the bottle from the boot of my car as even with current temperatures the boot (and cabin) gets very warm from the solar gain of my 'infinite height roof garage' - but of course I keep forgetting.

Just got the bottle from the boot, it feels cold just to prove me wrong but the car is parked other way round from usual so boot out of sun, on the bottle is stated "Use with 24 months of date on bottle if stored according to manufacturers instructions".

From Safety Data Sheet - "Storage conditions: Store in a cool, well ventilated area. Keep container tightly closed." - I knew I'd read it somewhere.

Date on my bottle is 16/09/19, I can't remember exactly when I bought it, December 2019 I think, from a local shop, certainly at that time I didn't think I'd have to worry about the use by date, how things can change. I think I've got about 50-75ml left.

It'd be interesting to see if a fresh bottle made any odds. And perhaps stored in a cool place but that's unlikely as with a tank that holds under 6 gallons I'm never quite sure on which journey I might need to fill up.
Nigel Atkins

So ... you are still saying it was 50 litres?
paulh4

Oh, I see what you mean, no, cheap keyboard with sticking non-repeat keys and poor operator/typist with sticking and non-sticking brain, but not necessarily in the right order.

500ml bottle treats 500 litres of petrol (1 ml per litre).

For those with 50 litre fuel tanks, they advertise the 500ml bottle as one bottle treats 10 tanks.

Such similar numbers could confuse a more feeble mind, and has.



Nigel Atkins

Stephan. (back on the 10th April) Not knowing how old your radiator is, I would opt for a new unit rather than trust a repair. Replaced radiator after my 79-B slipped off the jack pad and went through the bottom tank. That was over 10 years ago and it still looks new with no signs of seepage.
Yes, by all means replace the sensor along with the 2 rubber seals. If the sensor is still"good", keep it for a spare.

Let us know if you're car is cured.

Cheers,

Gary
79 MGB
Gary Hansen

Gary,
I think in the in the USA you seem to have access to a lot of services that are now difficult to track down over here and you seem to have access to a wider range of parts quality sometimes.

I bought a new rad about 4 or 5 years ago from one of the main specialist MG over here and it had to be returned, its replacement fitted and this year I noticed a fault with the shallow build quality, Not enough to do too much about other than a bodge repair but enough to confirm I might have been better getting the previous rad rebuilt, or perhaps risk one of the cheap Chinese ali rads that others seem to have found alright. Obviously if I'd have bought the cheap Chinese ali rad it would have been a duff one just for me. 🙂
Nigel Atkins

Not sure what happens with a carburettor street car on E10, later injected cars here can actually sense what fuel they have on board and reset their tune to suit but earlier injected cars like from the 90's or even early 2000's drink the stuff like it's going out of fashion, the ethanol content plays havoc with the O2 sensor reading
I had a 90 model Mazda turbo that would consistently return 400Klm to the tankfull but if i poked E10 in it, 250 would pull it up and it didn't have 100% performance, BUT you couldn't make it ping on the stuff where as it was a tiddle prone to the odd ping on real petrol
Really early injected cars designed for leaded fuel that didn't have O2 sensors struggle on E10,-Because their fueling is set by their pump/management and they have no feedback they run lean on E10
I was following a mate in his early 911 coming back from down South in the dark and the whole exhaust system started to glow in the dark, pulled him up to tell him and while we were talking the rear bumper bar started melting and dripping on the exhaust and up she went in flames--Luckily we got it out but the bumper was toast
The guys that run E10 race fuel in their race cars here have to go up a size on mains and down on air bleeds to get the mixture strong enough up in the revs compared to petrol, it seems the more you pour in the more they like it-especially turbos
willy
William Revit

Info from Shell when E5 first appeared was that the MGB should be fine, so probably the MGA, but prior to that less so. E10 was said to be 'unsuitable'.

Different issue though, the problem with higher rates of ethanol in cars like the MGB and older is more do with damage to fuel system components before it gets into the engine, than what happens inside the combustion chamber.
paulh4

The problem with cars that don't get used a lot and on E10 is the ability of the fuel to absorb moisture rendering the ethanol component of the fuel useless once it's hydrated--,if the fuel gets like this it tends to be milky looking,burns slowly and doesn't ping--similar to having water injection on your car, and at the same time it will be running lean, unless it's injected with an O2 sensor feedback telling it what it needs which will be heaps to make up for the 10% of dead ethanol
William Revit

Dear all,
this is, I hope, the final update on this thread.
I have replaced the radiator fan seal and clip, and this seems to have worked in that the wetness around the top of the radiator has been eliminated. While doing this, I came a cross some iffy connections on the radiator fan wiring, so I tidied this up with new connectors.
I installed a Distributor Doctor rotor arm, and went for a test drive. I drove for 22 miles without any incidents (the previous breakdowns were occurring after about 7 or 8 miles) and after letting everything cool down I checked the coolant level - no coolant lost as far as I can tell.
I don't think we will ever know the exact cause of the problem, but I think the rotor arm is chief suspect. I know I could put the old one back in and see if the problem re surfaces, but I am reluctant to do this because I don't like breaking down on the road - if I had my own test track ...
Thanks to everyone that offered advice and encouragement.
Best Regards
Stephen
SJ Elster

Well done Stephen, and thanks for reporting back.

Rotor arms have often previously been at fault so even if it wasn't installing a good one from DD could prevent future problems and stop the need to worry about such things.

I'm with you, I wouldn't bother trying to find the exact culprit(s) now, even if you could, I'd enjoy driving the car. You've sorted the leak, which also discovered and prevented possibly future issues by sorting electric connections and you've driven a reasonable distance as a test (now you can go for 50+ mile rides) and you've learnt not to take chances with possibly iffy parts quality, you've done enough.

Enjoy the 50, 100+ mile journeys. 😀
Nigel Atkins

I just picked up this thread and thought I'd share a couple of pictures of a rotor arm that drove me nuts with an intermittent misfire.

This rotor arm was supplied by Aldon Automotive in a new distributor. The second image shows the removed rivet where you can see burning that would have occurred when misfiring and arcing to the distributor drive shaft.

I now have a Distributor Doctor rotor arm and cap; not a misfire since 2017 when I experienced this problem.

Hope this helps spot duffers!

R





Richard Thompson

I've not seen one like that before, with hindsight that's obviously a wrong 'un that could get up to all sorts of mischief and nasties.

Do you mind if I share that with M&S (or S&M), A and T boys?

That's one for most wanted posters or Police 5 broadcast.

How on earth did Aldon justify that then, pertronix sent it in?. No wonder Pertronix were getting a bad reputation at one point.

Nigel Atkins

Looks a nasty piece of stuff--
An easy way to check a rotor button is to remove the dist. cap , remove the coil lead from the cap, then hold (with well insulated pliers) the end of the coil lead about 1/4" away from the centre of the rotor button and get your assistant to spin the engine over on the key as if trying to start it-
If you get a spark jump from the lead to the rotor then the rotor button is faulty
Only do this for 2-3 seconds as it can kill the coil if overdone

willy
William Revit

That's a weird one and no mistake! I'd have expected better than that from Aldon, but it goes to prove the point that not all red rotors are equal.
paulh4

I had what must have been a similar problem.
Aldon fitted one of their 'yellow' D45 dizzies with a Pertronix Ignitor to my Midget.

Some time later I had a sudden issue of very poor running, car finally cutting out - I had the original dizzy in the boot so changed it over and all O.K.

I sent it back to Aldon for checking as I assumed the Pertronix was faulty, they came back and advised the rotor (a red one) was faulty and replaced it.

Refitted the dizzy on receipt, it and its been OK since.

R.
richard b

Hi Nigel,

Please do share with other parts of this forum.

I have always been impressed with Aldon so did not question the rotor arm during investigation. It was new and from a reputable source. I don't know where Aldon sourced this rotor arm from.

I still hold Aldon in high esteem none the less, as the distributor that I have from them is great.

R
Richard Thompson

@ Nigel,

Just an after thought - if you want the original jpgs let me have an e-mail address and I'll send them over.

R
Richard Thompson

Richard, thanks I will do as it serves as a reminder and as you've found not considering parts because they're new and intermittent problems can be very frustrating and difficult to track down.

IIRC earlier Aldon at least was Pertronix (unless I've got that wrong.

I had an Aldon igniter head on my present Midget and it was good but still left the bottom of the dissy
used, abused and worn so when I swapped to a fully electronic (123) dissy the difference in all areas was noticeable.

Thanks for the offer of the originals, might as well thank you.
Nigel Atkins

Richard (Zumerset),
sorry I missed your post before - do bear in mind there are red (in colour) rotors arms, red (DD copied) rotor arms, and the original red rotor arms (DD) from the Distributor Doctor. - http://www.distributordoctor.com/red-rotor-arms.html
Nigel Atkins

This thread was discussed between 31/03/2021 and 27/04/2021

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