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MG MGB Technical - Electronic Ignition

We had such great response to our last problem we will try it again... We are thinking of switching our 1974 MGB to an electronic ignition system, any drawbacks anyone can think of. Any experiance with either the Crane or Igniter?
D Carr

Five years with a Crane on my 74 and no problems. FWIW, Clifton
Clifton Gordon

Thank you for your input.
D Carr

3 1/2 years with a pertronix and Flamethrower coil.

All A-OK. No hiccups whatsoever.

...knock on wood.
Daniel Wong

Pertronix. Major improvement and reliability.
Dan H.
Dan Hanson

5 years Pertronix w/ flamethrower coil...no problems. Make sure you upgrade coil to 40,000 & set your points as per the later years...
Robert Dougherty

6-7 years on Crane - 0 problems :-) Alan
Alan

Make sure you keep the points & condenser in the glove compartment, if the electronic ignition fails you're going nowhere, I found out the hard way!!
Ron
R. Algie

D Carr,

are you in the Boise area?? If you come back and read this, check out this site: http://clubs.hemmings.com/clubsites/ibcc/ For all I know, you may be in our club, but it has grown so much so fast, I don't think I'd know it. Cheers
Bob Muenchausen

Going on 6 years with a Pertronix and stock coil in my '74. Not a problem even on a cross-Canada road trip in 2000.
Simon Austin

Be sure to match coil with Pertronix Ignitor. I am just doing conversion but found that the normal coil might be a different amperage resistance than required by the Pertronix unit so bought 3.0 Amp Resistance Coil.
J.T. Bamford

I've used a Crane XL7700 (I believe) for hundreds of thousands of miles with great results.

The only problem is that, you may develop a bad connection in the wires that run from the sensor in the distrbutor due to the stress of the movement of the advance (this happened to me once in 300,000 miles). Dress in the wire to the sensor with care. A spare sensor is a good idea.

I picked up a Petronix as a spare and understand that it's a good system. In any case, you should definitely switch to one of these two systems. Points start to deteriorate the moment of first usage. These systems will maintain your dwell for good.

Steve
Steve Lipofsky

Thank you all so much. What a great response.
D Carr

With quality points, like Lucas originals, I never have to adjust the points for dwell between routine replacement and they would go on for much longer. I have heard of poor quality parts in the US that suffer from rapoid heel and point wear, but that goes for anything. I have never had points or condenser fail in 35 years, which is more than many users of electronic ignition can say. I know of several people with electronic ignition who have been caught out by failures on the road, and unless they carry points and condenser as a spare and can retrofit them, they are stuffed. Yes, an electronic trigger doesn't need adjustment or replacement like points, but at pennies every 10k miles it is worth it for the better reliability and the ability to do something about it yourself should something go wrong. I've tried full electonic systems in the past, not just an electronic trigger like the Pertronix, and found no measurable benefit to starting, mileage or performance over a correctly maintained points system. But again yes, a neglected electronic system will outperform a neglected points system ... until it packs up altogether.
Paul Hunt

I have the Pertonix system on my autox car. I think it starts faster,idles smoother, and gives smoother power all the way to redline. I couldn't even get the car to run until I installed their Flamethrower coil though. Next, the 'Second Strike' MSD box with rpm limiter.
Gotta do all I can to compete with the VW's.
Safety Fast
Dwight McCullough
Dwight McCullough

I had Petronix on my B for about 4 years and there was no problem with the ignition, but even though I had put them in a new Euro Spec Distributer the dwell would bounce around. I put in a Mallory Unilite this spring and there is a world of difference. I could now time my car as I wish and everthing works as it should. When I hook up a timing light the is no wobble on anything. The ability to have a stable timing also allows the car to run better. No matter what kind of system you put in it still depends on the quality of the distributer, and Lucus left a lot to be desired. Ed
E kulick

E Kulick brings up a great point. If your distributor is worn or has excessive end play in the shaft, it doesn't matter if you have points or electronics. Either way there will be excessive timing fluctuation and the car's performance will suffer. If you have problems with your distributor, spend the money on a quality rebuild and go from there. Personally, I have the Crane system. No problems with it on either vehicle I installed it on, so far...
Jeff Schlemmer

Many have claimed the electronic pickups eliminate timing flutter but like Jeff I just don't see it. Whilst shaft wobble with an optical trigger closer to and further away from the trigger might not cause timing flutter, shaft wobble across the face of the trigger will cause as much timing flutter as points. And with magnetic or inductive pickups to and from wobble at the firing point as well as that across the face of the pickup will cause as much flutter as points.
Paul Hunt

Paul,
I did notice a hugh difference in my TD when I put in the pertronixs. I knew I had a wobble in the dizzy, you could feel it. The points had to be reset quite often. I put in the pertronixs and the car ran smooth all the rest of the summer. The pertronixs did indeed compensate for the wobble in the dizzy. I have sent the dizzy of to John Twist over the winter for re-build, so I expect even better running this year.
Your point about carrying a back-up is well taken, I carry a spare Pertrinix in both the B & TD.
I have to disagree with you on the effects of the electronic points, I have found the cars start better & idle better. And the added benefit of not having to mess with the points is worth the money! I have heard the stories of the Pertronix failing, but I've had the same set in my B for 5 years now with no trouble, certainly couldn't get 5 years out of a set of points & condenser!
Robert Dougherty

Since I inherited my Crane XR700, I guess I could ask a similar question since the issue was raised with the Pertronix - should I be using a specific coil here? I have a Bosch "Sport" coil on there now.
Adam Birnbaum

I have to agree with Robert D. I installed a Pertronix unit in my Bugeye 3 years ago and the results were impressive. I had a fair bit of rotational 'slop' in the dizzy shaft. The Petronix compensated for the excessive play. Last year when I did a rebuild, I found the gear on the end of the dizzy drive spindle worn razor sharp, hence the sloppiness.
This spring I'm converting the '70 GT to Pertonix along with the coil. Can't wait to experience the improvement. I also agree, carry the old points & condenser for emergencies...
tim

I have two B's both 1800's one has points, the other Lumenition Magnetronic points. Quite frankly I can't tell the difference they both start easily and idle very smoothly. At nearly £70 for the Magnetronic system you can buy a heck of a lot of sets of points before you reach this figure. You must carry backup components in the car but I would also suggest that if yoiu rebuild the engine then it is easier to establish the static setting with points. In addition the Lumenition system can make for an erratic rev counter.
Iain MacKintosh

One point that no one has made, and one that people who use the "electronic ignitions" never mention, is the fact that the Lucas distributor requires annual maintenance. This includes inspection of the wear within the distributor shaft bushing, the cleaning of the inside of the distributor housing, inspection and lubrication of the mechanical advance weights and the points cam and cleaning and lubrication of the base plate. Then, you need to check the vacuum advance for proper operation.

Most of the people I know who have switched to an "electronic ignition" rave about how much better the car starts and idles than it did with the old, wornout points. Quite true. New points and condensor would also give the same improvement. But, after several years, the fellow who is still running points seems to have better performance. He cleans, inspects and lubes the dizzy when he installs his new points annually. The fellow with the "electronic ignition" does not seem to do this. The part is installed and the distributor seldom touched after that. Perhaps, when problems crop up, he will install a new rotor and distributor cap along with some spark plug wires. But, the mechanical advance seems to get grit in it because it is never cleaned. It gets some rust because it is never lubed. And, after a while, the mechanical advance is not working correctly.

Regardless of the triggering device used, annual distributor cleaning, inspection, repairs (as necessary) and lubrication make for a good running engine. There is no magic. Les
Les Bengtson

I bought my '79B 7 years ago with a Crane XR700 unit already in place, and I had no problems for several years. I developed an intermittent ignition problem 2 years ago in which the engine would not start and/or would shutdown occasionally, with no notice or predictability. The intermittent nature of the problem made it very difficult to diagnose, since every time I would start to narrow it down, the damn car would start up. Meanwhile, I was a bit scared to drive it much, since I feared the engine might die just as I pulled out in front of oncoming traffic.

I came to the conclusion that my problem was with the XR700 unit, only because I had finally (after almost 2 years!) eliminated all other possible defects. Dropped a new points distributor in and the car runs as well as it ever has, and my ignition problem has vanished.

So I guess the moral is, electronic ignition is great and low maintenance, but if there's something wrong in that box you'll never figure it out - as others have said, keep that spare dizzy in the trunk.
Derek Berger

This thread was discussed between 25/03/2004 and 29/03/2004

MG MGB Technical index

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