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MG MGB Technical - electronic ignition

Hi people
i am after your thoughts on changing to electronic ignition. I have been told that it will improve the performance of the car as well as the fuel consumption, but i have also heared that it gives no performance increase it just needs less attention than points.
I was just woundering what the majority of you out there thought about it.
Thanks in advance for your coments Andy
andy

Hi Andy, Speaking from personal experience I found the one fitted to my car gave no improvement that I could detect in performance. Having said that it did give more consistent performance, fuel economy and spark plug life than the points it replaced. By that I mean the usual deterioration as the miles were run up between services was eliminated. Basically it was install and forget.THT.Cheers,Pete. Sydney, Australia.
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Peter Thomas

Hi Andy,

I fitted full electronic ignition to my first car (a 2CV!!!) and it ran like a dream, started instantly and appeared to provide easier cruising speeds (but still around 70mph max!!)

I have a 78 BGT now and fitted the magnetronic ignition to it. With hindsight I shouldn't have bothered as it hasn't improved economy or performance and has created other issues when trying to diagnose simple ignition problems.

as a result of my "simple" ignition problems that I haven't been able to diagnose, I'm currently changing back to points (today in fact!).

all the best
Nick
Nick

Andy - Most adverts claiming improved performance, economy, etc from an electronic ignition are nothing more that advertizing hyperbola. The thing is that it works! Most people, after spending their money on an electronic ignition (magnatized fuel line or whaterve other amazing fuel economy/performance booster) will "see" an immediate improvement because they want to see it. An electronic ignition will make maintenance easier since there are no points to wear out and will make an improvement in drivability if there is wear in the distributor since there will be no change in dwell due to worn shafts, etc. So - while you will not necessarily see an improvement in performance/fuel economy, you will see an improvement in ease of maintenance and drivability (if you were having a problem with wear in the distributor), and yes, I put the Pertonix unit in my 67 MGB and have been quite pleased with it. One down side to an electronic ignition is that when it fails, you sit by the side of the road untill someone picks you up - one can't grind the points on the pavement and limp on home. When electronics fail, they are completely dead (I speak from experience of having sat by the side of the road with a car with electronic ignition and from having worked int eh electronic field for 40 years). Good luck - Dave
David DuBois

"it gives no performance increase it just needs less attention than points" pretty well sums it up.

All other factors being equal and up to original spec, the electronic ignition modules simply replace mechanical points which use the distributor cam to trigger them, with an electronic switching system triggered by either opto-electronic or magnetic means. After all, that is all that your points are - a switch to turn the juice on and off to the coil to produce current at a specific timing to ignite the gas a the right moment. Both systems do just that and nothing more. No miracle horsepower boost, no miracle increase in gas mileage.

Much of the benefit attributed by owners to the installation of these electronic points substitutes is probably more attributable to a good tune up than anything inherent in the generation of the spark by either points or an electronic switch. Yes, there is some small positive changes in dwell that can be programmed into an electronic unit, but the dyno generally says that the difference in power is insignifcant or, sometimes, non-existant. FWIW
Bob Muenchausen

I just put Crane XR700 on my 74 MGB last week and can't tell any difference because I think the head gasket is leaking now. A couple of years ago it got really hard to start and the problem turned out to be zero gap on the points. so at least I won't have problems related to a point gap or wear in the distributor. After I get the new head gasket put on then I'll experiment with wider gaps on the spark plugs. A lot of people keep a set of points & condenser in the trunk so they can switch real fast if the electronic system fails.
Ken thompson

Andy,

I agree with all of the foregoing comments.

I would recommend the pertronix system. It consists of a hall effect electronic unit that sits in place of the points that gives you consistent dwell and needs no maintenance. If the unit ever fails (it's very reliable) you can easily remove it (even on the side of the road) and re-install the points to get you going again.

Steven Rechter

Andy. This is a much discussed issue and commonly debated. If you would like my comments, go to my website, http://www.custompistols.com and click on MG articles. You will find one on electronic ignitions (which says about the same as above, but is expanded on the area of distributor maintenance) and the article on troubleshooting ignition problems. That will help you understand that the electronic points triggers are not a "set one time and never worry again" system as they are advertised to be. As Steve notes, the purchase of a system that will let you swap back to points if you have a problem on the road is desirable. Les
Les Bengtson

Lumenition black box. Removes points altogether. This means no sideways loads to bollox the distance between the points. Allows a (near) constant 'points gap' so far as the ignition system is concerned. Black box (not silver box) also recalculates the most effective dwell angle for the given RPM = bestter sparks.
Increasing the voltage for the spark means a more 'effective' spark that can cope with more soot and oil in the head. Worn engines will cope better with electronics of this type. BU...you must open the plug gap out to take advantage of this. standard (as sold) gap of 33 thou might be better than the all-out 40 thou. Higher comp ratio will require smaller gaps than standard, so don't go too far.

Problems:-

Lumenition Black gets confused by MGB RVI type revcounters (inpulse, with two white wires or a wire loop) so you need a late Jag RVC type (only, green, one white and an earth) revcounter and move the take-off to the other coil conection. Failure to do so will screw the dwell re-calculation

Lumenition eats cheap spark plug ends.


You get what you pay for, but it needs to be fitted in the correct way, not just the way it says in the sales brochure!

Personally, I use Lumen black on the MGC and a CDI system on the midget twin-cam. Work fine!
rob

Hi all,

I have the Lumenition Magnetronic module fitted to my '67 BGT. Here's what I feel has changed:

Advantages:
- No more squeaks/rattles from the disi (noises that came from the motion of the follower across the cam and from the weights at low rpm), thus making a quieter engine.
- Slightly more tractible at low RPM.
- No need to change the condenser every 3 months.
- Less electrical noise even than with a good condenser.

Disadvantages:
- Lack of resistance against the cam has messed up my timing slightly. The car just ain't as fast!
- If it breaks then I'm stuck. I've never had an engine completely stop due to points failure.
- It cost money.

I'm tempted to put points back on it, 'cos it was more swift when it had them, but chances are I'll leave the Magnetronic on until I get round to building a drive-by-wire 5-dimensional mapped ECU in the next year or so.

fwiw.
--
Olly S
Oliver Stephenson

Les, when did you put up the pages?? I will add to my list and disperse the knowledge. Great information!
Bob Muenchausen

Bob. Started putting up the articles I had written a couple of months ago in hopes that it will be of use to others. Might also get me some feedback on any areas which might not be clear. We have not gotten the links set up yet, but your site and Paul Hunt's are on the list. Les
Les Bengtson

Andy,
If you are serious about an electronic ignition, don't go with a band-aid. Throw away the distributor with it's gear slop, timing chain wear, cam shaft twist, advance weights and springs. Go get a crank-fired, computer controlled iginition system.
Leland Bradley

Thanks for all your comments people. from all the info you have supplied i think i will stick with the old points and spend the money on a mild cam. it seems the only advantage to electronic ignition is less fidling with the car. I much prefer to have a fiddle its all part of having a MG isn't it.
Thanks everyone Andy
andy

The main reason why I have gone to electronic ignition (on the V-8 and plan to also on the 1100 when it is ready for the road) is that I do not trust current production Lucas condensers.

The old Lucas condensers (with the metal boss at one end to which the pigtail lead was soldered) were pretty much bulletproof. The ones you get now (with the pigtail lead disappearing into the end of the condenser) are much lower quality. They remind me of all the awful "hecho en Mexico" electronic capacitors you find at Radio Shack.

I have seen three failures of new style Lucas condensers in the last 5 years or so, one of which was on a Jag XJ6 where it is nearly impossible to get to the distributor cap clips without some form of special tool. On cars like this (or others like the mga twin cam, where the distributor is very inaccessible) electronic ignition is a must.

Cheers,
Paul Kile
Paul Kile

This thread was discussed between 05/12/2001 and 06/12/2001

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