MG-Cars.net

Welcome to our resource for MG Car Information.

Recommendations

Parts

MG parts spares and accessories are available for MG T Series (TA, MG TB, MG TC, MG TD, MG TF), Magnette, MGA, Twin cam, MGB, MGBGT, MGC, MGC GT, MG Midget, Sprite and other MG models from British car spares company LBCarCo.

MG TD TF 1500 - Oil pressure on start-up

Couldn't find anything in the archives, sorry if this has been covered before:
Starting the TD, I have to turn the engine over without the key until I register some oil-pressure, which takes about 10-12 seconds. This can't be good for the starter and it's embaressing as the neighbors think I can't get the car started! I have a spin-on oil filter adapter and use a WIX filter, which has good anti-drain features. I've tried just starting the car, but it sounds horrible....comments?
Robert Dougherty

Check the archives for "priming"... there are a couple of ways of working oil through the system first.... soak the filter... use the priming bolt on the pump if a late model. Force oil through the banjo bolt in the head... squirt oil into the cylinders...
Took about 10 seconds to get oil pressure up when I first started it after priming.
gordon lawson

Are you saying this happens every time you start it? Unless you just changed the filter and the car sat for some time, pressure should pop up quickly. What kind of "terrible" noises does it make?
George Butz

George,
Every time I start it if it's been sitting over 10 hours. The noises are the "dry" start-up noises you get with the cannister filters, engine noise sounding like no oil in the valves.
How quick does the pressure come up? Before I changed the old cannister, I'd get a "dry" start for about 15-20 seconds. Now, it's about 8-12...is that right? I expected instant oil pressure when I put in the spin-on filter.
Robert Dougherty

Robert...

Not sure I totally understand why you're not starting the engine immediately. Oil pressure will normally build as soon as the engine starts. Granted it won't be at 60 lbs immediately, but it should go to 10 - 20 lbs within seconds.

How long does it take for the oil pressure to build when you start the engine without first cranking it with the key off? My point is, I don't see that spinning your engine over with the starter motor is doing anything more for your engine than immediately starting it.

Gene

Gene Gillam

Let me second what Gene is saying. It's normal practice to spin a newly rebuilt engine WITH SPARKPLUGS REMOVED to test for oil pressure. In that case, you aren't stressing the bearings, and you should get a pretty fast spin from the starter with no compression.

I don't see what advantage you get by spinning the engine without starting it, once the plugs are installed. You may get unburned gas in the cylinders, because there may be some in the carb floats. The starter isn't going to spin the crank all that fast against the compression, and the bearings will still be stressed.

I just start my TF, and I normally have oil pressure within a second or two. I actually don't know how long it takes, because it's always up when I look up from the starter pull. One of these days, I have to remember to watch the oil gauge when I start the car. I normally use enough choke for it to idle at about 1500 to 1800 RPM for a minute of so. I have a TF 1500 with the canister oil filter integral to the oil pump.

I'm betting that if you go ahead and start the engine, you will have oil pressure quickly, because the oil pump is just going to work a whole lot better at normal operating revs than the ~500 RPM of the starter (just a guess). Do a test and see if this is so. If it takes more than a few seconds at normal running speeds, then maybe think about doing an oil pump rebuild. Moss sells a rebuild kit. It isn't a technically difficult job, but it's fairly labor intensive.
Mark B.

Here's a couple more suggestions. I think these are unlikely to be the case, but I'm just offering them as additional things that you may want to check.

Another thing to look at is to make sure that you have the correct dipstick. I don't know if this can happen with a TD, but the wrong dipstick can cause you think you have enough oil when you don't. If the oil pickup has a bad gasket, it can make this worse.

It might be possible to have a problem with the seal on the oil inlet pipe, which goes through the edge of the oil pan. If it was able to suck air, that would definitely cause an oil pressure problem, and if that leak were on the inside section of the gasket, you couldn't see it as an external oil leak.
Mark B.

Defintely not what my and the other cars around here do- the pressure pops up withing few seconds at most and I can't recall any cold-start up noises either. I have heard various people advocate the crank until pressue idea, but if run recently shouldn't be needed. If my 280Z sits for a month or so, I do turn it over for a few seconds first (fuel pump switch deal). What weight oil do you use? The valves in my engine are acually noisier when it is really hot- real quiet when cold. Possibly you are hearing bearing knock instead? Ideas above of course right on also. George
George Butz

Bob,

I’m not sure that I understand exactly what manifest the change in starting oil pressures, and am going to guess for the purpose of this response, that you installed a modern spin-on oil filter adapter. It wasn’t clear to me exactly what happened between the old and the new pressures. But if it was indeed, the installation of the new oil filter adapter, then here’s another possible source of trouble.

I believe there are several manufacturers of the spin-on oil filter adapter, however I’ll deal only with Bob Grunau’s as it’s his (manufacture) covered in his article in the October TSO.

If you get the TSO, you will see that the way the filter body is drilled, its entirely possible to have some incomplete or blocked gallery. Look at the top of page 27 and this cut-in-half filter body will make that possibility clear.

I suggest you remove and blow compressed are through your filter body checking that the air flow is complete and not blocked by some incomplete or badly-drilled oil gallery.

Gord Clark
Rockburn, Qué.
Gordon A. Clark

It seems to me that the bottom end of this engine may be in fairly poor condition. Mark B was getting around to this by saying that the oil pump may be due a rebuild, but the crankshaft and bearings may also be in poor condition. By fitting the spin on filter you did actually improve the situation but there is still noise on start up due to oil draining back through the pump and out of the bearings. You didn't tell us what your oil pressure was, hot running and hot idle. Another give away is that with an idling hot engine how long does it take for the oil pressure gauge to drop to zero as this is a good indication of the tightness of the system.

Don't crank the engine over when cold, just start it so that pressure rises as quickly as possible but don't let the revs rise above 12/1500 or so.
Iain MacKintosh

Robert
Im one who turns my engine over with the key off until oil pressure shows on the oil pressure gauge. This gives me piece of mind and I do it every time the cars has the oil changed or sits for a long time. This was taught to me by some of the first rebuilders of the 60s and 70s. You have indicated that if you start your engine without doing this, that your engine makes a dry start up noise. If you turn it over with the key off until the oil pressure shows on the gauge, dose it still make this dry start up noise. My bet is that it dose not. I will agree with the others that there is probably something other wrong with your car that needs attention. I have a friend that has a TD that the engine was recently rebuilt and after sitting for a week or so, upon start up it sounds like it has a rod knocking in it until the oil pressure builds up. Then every thing sounds normal. This only takes a few seconds but the noise to me is frightening. It sounds as if the engine is running dry for these 5 to 10 seconds. When the engine is turned over with the key off until the oil pressure builds and then started it dose not make this noise. Their engine oil system in my opinion needs attention also. IMHO you and they are probably having the oil drain back into the engine sump. Most likely cause again, IMHO the relief ball valve and spring. The ball could be worn and the spring no long has the right tension. I personally would continue to spin the engine with the key off until you see oil pressure until the problem can be corrected. As far as what the neighbors think and you being embarrassed. You will be a lot more embarrassed if they hear that rod through the cast iron engine sound. Roger
Roger Thompson

>Another give away is that with an idling hot engine how long does it take for the oil pressure gauge to drop to zero as this is a good indication of the tightness of the system.

How long should it take? It takes my engine only about 5 seconds for the oil pressure to drop to zero after it stops, and I have about 1000 miles on a complete rebuild.
Mark Barrington

Mark, there is no definitive time for the pressure to drop to zero but i would say that five seconds on a hot engine is pretty good. With your engine cold this could well be 15 - 20 secs which all gives an indication that the oil system is capable of holding pressure due to tolerances being quite tight. If I had a hot engine which was idling and when I turned it off the pressure fell like a stone say within a second or so I would be pretty sure that there was wear somewhere along the line and that the life of my motor would be getting fairly limited. Don't worry as yours seems fine.
Iain MacKintosh

Roger,
Exactly! When I turn it over without the key until there is oil pressure, there is no noise...should I start it up without waiting until there is an indication of oil pressure I get the noise you describe. With my 69 B I had the same noise with the cannister filter, as the oil would drain back into the sump, when I changed to the spin-on filter the problem went away. I had expected the same with the TD when I changed from the cannister. While it is better, it still takes about 5-8 seconds for an indication of oil pressure. I'm due for an oil change, I'll change the filter and see if it improves. Makes sense that the oil is draining back into the engine, I had thought the spin-on filter would prevent that. Have to agree, would be more embarrassing to throw a rod! Will continue to monitor, relief ball & spring sounds about right.
Robert Dougherty

I'm in Roger's camp. I follow the same procedure with my engine. I'm using Bob Grunau's adapter with a Wix/NAPA 1515 filter that contains an anti-drainback valve. If it's been more than a week since I last ran the engine I crank it with the ignition off until I see movement of the oil pressure gauge. The engine is well broken in with about 5,000 miles since the rebuild; carries great oil pressure, cold or hot.
Bud Krueger

Does your spin on filter have a check valve in it ? Many modern ones do. Perhaps the system has to overcome the check valve pressure/resistance before oil starts flowing through it. I think I have read warnings not to use a spin on filter with a check valve in spin-on conversions.
Larry Ayres

Robert
There is an “oil filter study” by Russ W. Knize that you can look up on the inter-net, I tried to link it but I'm some what computer challenged. I use Bob Grunau’s adapter as Bud does above and the Wix/ Napa spin on filter. If you read the oil filter study, you too will use these filters. On my car I have the vertical filter, not the one attached to the oil pump body. Even if my oil lines and upper engine drain back into the sump, the filter remains full. The only amount of oil I pump up with the starter is what has drained back from the oil lines and the top of the engine. When I start my car after it’s cold I spin the engine until I see an oil pressure reading on the gauge, every time. I don’t after it’s hot and running and the oil pressure has been up. I once changed the oil and if I did not do this little trick I would have ruined the engine as it had lost it’s prime. The only way I knew it, was no oil pressure reading on the gauge. So I got out and re primed the oil pump, un screwed the filter and filled it with oil. Then turned the engine with the starter until I saw oil pressure reading on the gauge. If I start my engine cold the oil pressure goes up with in a couple of seconds, I just use this starter with the key off trick to turn the engine until I get a oil pressure reading for my own piece of mind. Once the engine is switched off there is no reading on the gauge, it just goes back to the peg/zero. Anyway this has always worked for me and I would rather replace the starter than the engine. Roger
Roger Thompson

Roger,
That's how I start my TD after it's been sitting also, guess I'm not alone! I use the NAPA Gold/WIX 1516 filter.
Robert Dougherty

Of course there will be no noise if you crank up the oil pressure on the starter as that's a completely different condition with the crank driving the pistons and the big end bearings carrying no load. However it must be said that a recon engine with factory clearances will not knock if started directly up and before oil pressure is established as there is little or no clearance to allow slack with the attendant rattling. The oil film present will protect the bearings until pressure backs up the oil supply.

Unfortunately knocking on direct startup indicates wear in the crankshaft and bearings by varying degrees and whilst cranking firstly on the starter will bring the pressure up and elimanate the death knock it is only really masking the real problem.
Iain MacKintosh

The study that Roger is referring to can be found at http://minimopar.knizefamily.net/oilfilterstudy.html and is well worth reading, IMHO.
Bud Krueger

I don't seem to have any noise problem, either cold or hot. I am using the Fram PH3600 cartridge.

Does anyone know if this does, or does not have the check valve. Should I consider changing to the Wix/NAPA 1515 or 1516?

Gord Clark
Rockburn, Qué.
Gordon A. Clark

After having read the very interesting analysis of the various available filters that Bud has referred-to, I am convinced that the Fram filter I have been using, should be replaced with a Wix 1515.

Good reading, Bud. Thanks.

Gord Clark
Rockburn, Qué.
Gordon A. Clark

This thread was discussed between 15/01/2006 and 18/01/2006

MG TD TF 1500 index

This thread is from the archive. The Live MG TD TF 1500 BBS is active now.