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MG MGB Technical - Updating Ignition system

I'm considering installing a Pertronics unit and Lucas Sports coil on my 74B. Has anybody tried this combination with success or disaster? Both are on sale now thru February. I'd appreciate any comments.
Bob Ekstrand

Bob. Check out the archives as this has been a hot topic over the years. My daughter's 77 is running a Lumenition system with a Sports Coil (system converted to full time 12V input) and I am running points with the Sports Coil on my 68. Do not notice a great deal of difference between the two myself. Les
Les Bengtson

Bob:

I am running just that combination. Only real reason to run the Petronix is to be rid of the points and condenser maintenance. No real performance increase unless your disributor is old and wobbly. I keep a set of points and condenser in the glove box for the day the petronix fails; they seen a bit delicate fron what I read on this BBS.

Pete
Pete

Bob,

Just like Pete, I'm running the same combo on my '67(converted to negative earth) I also had the same on my '70. Anyway, as Pete says, no real performance difference to speak of. The most important thing that I've noticed is that the timing stays spot on much longer(almost indefinitely) as compared to the points system. This means smoother running and less power loss with fewer tune-ups.

BTW make sure the two wires that run around the rotor shaft inside the cap stay away from said rotor as it could wear through the wire insulation and cause the system to ground out and miss-fire. This happened to me when I unknowingly pulled a little too much on the two wires from outside of the dizzy. I slipped some heat-shrink over the affected section and tied a zip-tie around the two wires on the inside of the grommet to prevent the same thing from happening again. I've had no problems since, and that was a year and a half ago.

One more thing. With the higher capacity of the electronic swicthing and higher output of the sport coil, you can run a larger plug gap of .030 or .035 as opposed to .025. They say it improves combustion, hence power/fuel consumption is impoved, although I can't say I've noticed it.
Jared Snider

I just had my first pertronix ignition die on me this last Friday. I had it on the car for 2 yrs. Compare that to 9 yrs with Crane XR-100 setup. The Pertronix is a clever design and far and away the simplest to setup. However, I am NOT impressed with its longevity. There have been others who have posted similar results on this BBS and others who have done better, so take that for what its worth. Today I go to the parts house for a set of points and condenser. {Do I hear Paul Hunt chuckling??? ;-) I deserve that! LOL} Sometimes there is no substitute for simplicity.
Bob Muenchausen

The first car I put the Pertronix on had bad valve guides and iffy compression , was hard to start when hot , odd misfire @ idle due to the loose valve guides , the usual old MG situation ~ the Ignitor _immediately_ improved starting hot or cold and idle too , nary a miss , ever . power was the same but smoother , milage went up one or two MPGs as I was running milage checks at the time .

I cannot say enough good things about it , over 40,000 miles and still lights off instantly like to-day @ 04:30 on my daily driver .

-Nate
(yes I fixed the valves!)
Nate

Thanks for the great input guys!
Bob Ekstrand

This thread was discussed between 13/01/2002 and 15/01/2002

MG MGB Technical index

This thread is from the archive. The Live MG MGB Technical BBS is active now.