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MG MGB Technical - Electronic ignition

Just started rebuilding a 1969 MGB-GT which has been sitting about 8-10 years. New master cylinders wheel cylinders etc. Got it running last weekend but runs rough. Thought about putting electronic ignition on it. Anyone have any suggestions? Is this a good investment or not, and if it would be, what would be a good one to install. PSC
Paul

Paul,

In all brutal honesty - it's a great investment once you figure out why it's running rough to begin with.

The original points/condenser set up is remarkably long-lived and reliable - and has the added plus of being cheaper than hell to tune up. For about $40, you should be able to get plugs, wires, points, condenser, cap & rotor. Do these first (and check the timing too), clean the float bowls (but otherwise do NOT mess with the carbs - yet), and see what happens.

The beauty of points/vs electronic, is that the points system will graaaaaaaaaadually go bad after you tune the engine - allowing you lots of time to plan your next tune up. The electronics don't go bad often and are very well designed and executed these days - but when they go bad, they commeth like a thief in the night - and that's usually a rainy night, when you've got a new suit on, and your cell battery is dead, and your two hours from home...

My tuppence!

Cheers,

Tom
MG Tom

Personally, I put the Crane system on my B right away to eliminate problems with the points or worn lobes inside the distributor. You will need a Lucas cap and rotor - not an aftermarket model, or the unit will not fit inside the distributor. It has been terrific! No problems, no worries!
Jeff.

Jeff Schlemmer

Or the pertronix system. Either elecetronic points substitute will work well enough, as do the OE points.

Tom has probably said it as well as anyone. This is one of those choices/improvements which net you nearly zero in performance, and only extended timing consistency over time - until any of them goes to hell. And Points are not bullet proof either. Buy the OEM Lucas points and condenser to get the most out of them.
Bob Muenchausen

The Petronix is dirt simple to install. Red & black wire to the + & - on the coil. Throw everything else away. But that is most likely not your problem. Can't imagine carbs ten years old not needing a rebuild.
Jim Mindy

Jim Mindy. Hope to see you at All British Car Day this Sunday. Glad you have made it back safely.
MG Tom. Please check out my website at: www.custompistols.com and click on the articles, then electronic ignition. I would appreciate your comments.
All. The problem I have with electronic ignitions is that most people consider them a "fire and forget" (to use an old military term) system and do not realize that the rest of the distributor still needs, at the very least, annual inspection and lubrication. This requires that you remove the "electronic ignition", strip the distributor, clean it, inspect it, then, if the parts are good, lubricate it and reassemble it. Then, you have to re-install the electronic ignition. Recently, I rebuilt a distributor as an Arizona MG Club tech session. When I put the distributor shaft on the lathe and used a dial indicator, the shaft was .010" out of round at one point (directly opposite where I had zeroed the indicator). I have found about one in five distributors to have more than .003" of wobble in their shafts. The electronic ignition will compensate for this problem, which is a good thing. It will not compensate for bushing wear, bad vacuum advance or bad centrifugal advance. The best time to use an "electronic ignition" is with a newly rebuilt distributor. In that case, it will give you about 30K miles of excellent operation without having to replace the points or deal with the slight degradation of performance that points bring about over time. With the 25D distributor, I run points and replace them a couple of times a year. (I race my 68GT and am looking for max performance in a street car.) With the 45D, I think I would seriously consider the electronic ignition. Les
Les Bengtson

i have rebuit my eng. on my 71 b. i have changed just about everything that you can to increase the hp,most of the work was done to the head, ported,polished, decked. the block was board 30 over with a kent cam, road grind.they called it. i did change the whole dist. i put a mallory duel point in and it was fine. then i went to a unilite made by mallory. the reason was the cost of all the parts in it for a tune up(2 points,cond,cap,)not to mention that a speed shop is near by when the thing does crap out. and yes they do without warning. the condensor died. that is one reason i went to elec.the other was piece of mind. all i carry is a spare ballast for the dist. the only probem i have is that my tach will not go above 2500 no matter how fast i go. if any body has a clue to why Please write me. i still have the stock tack
don baker

Pertronix, Luminition Crane.
Does anyone have any views as to which is the superior performer and hopefully the easiest to install.
mark smith

Pertronix, Luminition and Crane.
Does anyone have any views as to which of these three is the superior performer and hopefully the easiest to install.
mark smith

I had an Allison (Crane) --- after many years of reliable use, it turned flaky and my expert advisor reccommended Petronix. Also, the unit was barely able to fit under the curved cap which goes with the 25D dizzy.

Dan

Les,

I liked your article, by the way. My concern is that many people throw good money after bad, end up with no better results than they initially had, and then blame MG, England, The RAF, Her Britanic Majesty, and just about anyone else they can think of.

Modern advances in our hobby are wonderful and everything than can improve safety and reliablity should be considered. I've just seen too many guys out there trying to get four more horsepower out of the engine, while having no idea what their rear brake shoes look like - for instance.

Having said that, it's our money and our hobby so everyone should do what they like - but use as much wisdom as one can muster!

Cheers all,

Tom
MG Tom

Mark, Luminition is probably the easiest to install, but they are all similar. None will offer better performance than the next. They all offer timed spark. Period. If you have a performance motor with sidedraft webers, try the Crane XR-3000. Used with a PS92 coil it is the highest output ignition system available for an MG. But the $$ for horsepower tradeoff is a loss. If nothing else, the coil is quite attractive.
Jeff.

Jeff Schlemmer

Paul-
I use the tried-and-true Crane/Allison unit along with Crane's 40Kv coil and silicone leads. Just to play it safe, I protected the electronic module from the heat of the engine compartment by putting it under the dashboard. My modified engine fires right up and never misses a beat. Ain't progress wonderful? However, Les is dead right about the need to maintain the internal mechanisms of the distributor. Neglect that and you'll be mystified by the creative ways in which your ignition can go astray.
Steve S.

My daughter's 77 has a Lumenition which was installed by a previous owner about 15 years ago. It is still running great. I used the original Allison (now Crane/Allison) many years ago on a Corvette and it worked well. Petronix has a good reputation on this board and the midget board. I believe you would be well satisfied with whichever system you picked up. One thing about the Lumenition (do not know about the others) is that it can be set up to run with a 12V Sports Coil. This was recommended to me by a ex-pat Brit engineer and has worked very well for the last two years. Les
Les Bengtson

This thread was discussed between 17/10/2001 and 25/10/2001

MG MGB Technical index

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