Yesterday I did the M151 to M38a1 electronic ignition conversion. It is actually a breaker-less ignition conversion using the Swedish M151 conversion kit. This kit is running about $50 whereas the Pertronix conversion kit runs about $150, but it is a drop in kit. I found the instructions here: http://www.willysmjeeps.com/v2/modules.php?name=Forums&file=viewtopic&t=1541&highlight=electronic , but they only provided an overview of the process. He included the main points like where the Hall sensor should be pointing and a basic idea about where the tab slot should be located. It says that the rotor will have to be modified, but doesn’t tell you how to do it.
I removed the breaker plate and using the drawing above, marked the location of the new tab slot with a pencil. I removed the new module and started cutting the slot with a Dremel tool and finished up with a couple of small machinist’s files for a tight fit. Then I cleaned out the metal shavings with compressed air and brake cleaner. This also removed the paint everywhere it touched and cleaned out some built up varnish or gummy oil on the shaft because it turned much better!
I reinstalled everything after oiling the pivot points on the counterweights, springs and shaft. The retaining spring was kind of a pain to reinstall and the wires from the module were actually a little short, but they did reach the coil.
As mentioned before, the rotor is supposed to be modified, but I haven’t found any detailed info about how to accomplish this. When I do, I will update this writeup and the video.
Here is the video that I made, showing some of the main points of the conversion. It is not professional or not brightly lit – it was taken with my phone, but you might still be able to get something out of it.
Before I started the conversion, I cleaned up my used starter that I bought at the rally this weekend with some brake cleaner and painted it. I installed it in the Jeep before I re-installed the distributor. I sure am glad I set the motor to TDC on #1 cylinder before I removed the distributor – made life a whole lot easier when I put it back in!
I hooked up the battery and ignition cables to the starter and distributor and hooked the battery cable back up at the battery. I hit the starter pedal and it sure did turn over ALOT slower compared to the 12v starter (it is supposed to turn over slow with a 24v starter, so that’s a good thing!). It started right up and ran ALOT smoother than with the points – without even fine tuning the distributor! I ran around to the distributor to fine tune and my hand touched the rag covered battery cable at the starter – it was hot! I waited a few seconds and touched it again – it was HOTTER! So I closed the hood quickly and disconnected the battery cable. I think the starter switch is probably grounding out because the insulator inside it is burnt – I’ll get to around to checking that today hopefully.
Overall, a success!
Rebirth of an M38A1 