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MG TD TF 1500 - Petronix ignition

I have a 54 TF and have had periodic backfiring and misses on acceleration (not always, but sporadically). I am fairly convinced that the problem is ignition and not carbureation. I have replaced points, rotor, condenser and cap. I have also installed bumblebee wires. My question is will Petronix Ignition (Moss#222-572) improve performance? Anyone had experience with this installation?
Regards, Seamus

Hard to say Seamus. Unless you track down the failing part, it may do no good at all. I've put one in my TF. Set it and forget it mentality.

Posted - 09 December 2007 : 00:53:07


I can recommend fitting pertronix electronic ignition, it fits neatly inside the distributor on the points plate. I fitted it on my last classic a triumph TR6. It is very easl to fit, takes approx 5 mins. I have now also fitted it to my newly restored 1953 MGTD. I found the petronix ignition system improved starting and performance on the Triumph TR6, can't say whether it improved the MGTD as when I bought it it was all in bits.However now Its restored with the petrinox ignition fitted the car starts immediately and preforms well.

Other suppliers in the US are and

Hope this help Chris
C A Pick


You've done all the right things so far. I suggest you replace spark plugs, too. Personally, I like NGK plugs.

I'm in Massachusetts, too. I have additional spares for all the ignition parts, which you can borrow. If interested, contact me directly via e-mail.

Good luck.

Larry Shoer

I also have a pertronix in my TD. It has never run better, and there is a noticable improvement in performance (5% dynomometer measured on an MGB). It is worth it for that alone. It is also cheaper in the not-so-long run in both parts and labor.

I recently started having a problem similar to yours, and removed the cap to find brass filings in the cap. I cleaned them out and it went away, for a while, and came back, I cleaned it again. You might check for this.

I had the distributor rebushed prior to this happening (a 1year before), there is no play, but I have a black polycarbonate cap from Moss and a rivet free rotor that I got somewhere else on the internet. Not sure if there is a problem with either of these fitting.

If you have a rotor that has a rivet holding the brass on, replace it. It can short internally to the shaft as the plastic breaks down. This can also cause major problems, especially missing, as it did to me.

Larry Ayres

Seamus - have you checked the pistons in both carburetors for smooth travel in the vacuum chambers? I had a continuing problem of stumbling when accelerating that I finally traced to a gritty feel when the pistons were lifted. Cleaning the piston edges and the interior of the vacuum chambers cured the problem. Cheers - Dave
David DuBois

I had a problem similar to what you described and wrestled with it for a long time before I finally gave in a sent the distributor off to Jeff Schlemmer at Advanced Distributors so that he could work his magic on it. Two or three days after taking it to the post office, I got a phone call from Jeff. He said, "We gotta talk", apparently, that distributor had been rebuilt once before and there just wasn't enough left to do another rebuild. After discussing how I drove the car etc. he said, I'll build you a new distributor using a 45D and installing a Pertronix". I said "go for it". What I got back from Jeff was a better than new distributor. I installed it in the car and that car has never run better than it does now. I have no commercial interest in what Jeff does, just a very satisfied customer and highly recommend his services.

Cheers - Dennis
D L Rainey

I have had 3 units go bad, 2 were warrantied no questions asked. 3rd time in 5 years, they would not honor their warranty, with out my receipt, which I could not find.No parer work was asked for the other 2 times it went bad.
Len Fanelli

I've given a couple of tech sessions on Pertronix installation and get contacted periodically. Out of perhaps a dozen instances I've only found one where the unit was faulty. Most problems have been with folks just not following the installation instructions. This is especially so for folks with positive ground systems. My original points plate rests very nicely in a little box in the tool box, just in case.
Bud Krueger

Bud, Keep it in your toolbox, & remember to use it as a first guess in any diagnossis. I always suspect any non factory installed part as the customer concern, many times the non OEM has been the issue.
Len Fanelli

We have a gal here in Rockburn who had two fail on her TF. Joe Curto replaced then overnight. I have a Pertronix too, and tend to forget that the cap should be cleaned from time-to-time. They tend to impart a sense of infallability.

Gord Clark
Rockburn, Qué.
Gordon A. Clark

I run a Pertronix and love it. One thing I did find when I replaced my points was a "bad spring" on the advance under the plate.
One of my springs was rusted under there and that could cause problem you describe.
Make sure you order the correct Pertronix unit for your car! Positive or Negative ground makes a differance!
David 55 TF 1500 #7427
David Sheward

What's a bumblebee wire ?? First time ever I see this expression !
Remo Peter

Ot is a copper stranded spark plug wire.

It is called "bumblebee" because of the yellow and black stripes as on our
large bee ( not a honey bee, but much larger).
It has coarse stranded copper wire encased in about 5/16 inch diameter insulation which is striped yellow and black.

It was the premium spark plug wire in the "50's.
Don Harmer

This thread was discussed between 06/01/2009 and 09/01/2009

MG TD TF 1500 index

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