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Jupiter breakerless ignition

From: Peter Tribble
Category: Technical
Remote Name:
Date: 13 Oct 2005
Time: 13:25:58


For anyone interested in installing breakerless ignition for a positive earth system, I have followed Eric Aldcrofts lead and successfully put a pertronix "ignitor" in my Jupiter. My car is a 1952 model E2SA665 and has a DM2 40571 distributor. This has no external box of tricks to find room for, instead it is a simple direct replacement for the contact points and condensor inside the distributor, working off a magnetic hall-effect pickup. I also installed their "flame thrower" 40kV coil, although I am sure that a standard one will work nearly as well, or the lucas sports coil if you have one. All you have to do after replacing the contacts is change the wiring of the coil as follows: The '+' side goes to an earth point, the '-' side goes to the ignitor, and the other wire from the ignitor goes to the ignition switch. This last wire used to go to the '-' terminal of the coil. Finally retard the ignition a few degrees before starting, and fine tune it from there. I have found that there is a strong healthy looking spark, the idle is less lumpy and the engine pulls strogly through all the revs, but the biggest bonus is that I should not have to adjust it ever again! (I hope). There is a good MG article on pertronix here and a comparison of coils to use with electronic ignition here I bought the pertronix bits online from a Michigan dealer at I took a slight gamble and ordered part number P-LU-142AP12 listed for a DM2 40510, or 40561, distributor. There are many others listed for more common models such as the 25D series. The grommit in the kit in fact would not fit the exit of my distributor since there were a couple of prongs sticking up from the base plate holding the previous plastic connector. You would have the either adapt the grommit, remove the existing progs or do as I did and install a base plate from 25D4 that I happened to have lying around. For more info on pertronix see These do look suspiciously like the kits sold by Aldon Autos in the UK online, however the latter did not have as comprehensive a parts list for these ignitors as the Michigan dealer. Besides which the exchange rate is so good at the moment that the prices are far less to import it from the States. I hope this helps anyone who is looking to do the same thing. Peter Tribble.

Last changed: November 19, 2008