The truck wants its 3rd points cleanup. So there's some issue going on in there. Maybe the condenser died? Anyway, the plan is to finally install this pertronix modual I've had kicking around since the engine rebuild. read through the paper on this then looked at the pictures in the M37 manual..
The first thing that strikes me is what orientation does the plate go in? I don't have the truck here to look, just the pertronix unit and the manual.
Do I have to knock off the nubs on the side? And, the cutout doesn't seem to line up with the hold down screws like the M37 one does.
That mounting plate looks a lot bigger than the one mine came with, which was a much smaller u-shaped plate that screwed right down without any mods. Methinks you may have the wrong one?
I'm sure someone here will post a pic of theirs, I'm not near my truck right now.
Hmm, I was wondering. This is the Third one I've dealt with. The first two were no big deal, Chevy & Olds. In the instructions on this one, they say you may have to file off the nubs. And, any way I line it up seems to point the wires in the wrong direction.
I forgot where I got this. Maybe I should go dig through my files?
Still running the dist vent lines? Most say it is for cooling the coil, but I've never seen that make much difference.
The factory dope is it is necessary to carry off corrosive gasses produced by the arcing points. The Pertronix SS switching modification would seem to eliminate the requirement.
To wit, the GMC G742 2.5 ton has the same vent setup, but the coil hangs mostly outside the dist housing.
I hear what you're saying, but I wouldn't underestimate the importance of keeping the coil cool. It's basically a transformer, and if you've ever felt one working (think wall wart) you know they get hot. The windings in the coil are in an oil bath to transfer the heat from the windings to the metal shell of the coil. The metal shell would normally transfer heat to the air around it, as in automotive applications, but as you know, in the M37 it's encased in the distributor housing where it is not exposed to the ambient air. That sucker will cook in short order without external cooling. I believe Charles mentioned on here, not too long ago, that the coil failures he's seen have always been related to lack of cooling air.
I don't want to sound like I'm coming off as the M37 Ignition Coil Cooling Police here, it's your truck so do what you want, but you can see that Chrysler made a dedicated effort to make air flow into the distributor. Without a vent condensation will form inside the distributor each time the truck is used, ultimately resulting in a rusty mess in there. For those reading this post who might be on the fence about installing the distributor vent lines..........do it. If you piss off Mother Mopar she'll leave you dead on the side of the road at the worst possible time.
Saw my name mentioned concerning vent lines. Yes they are hugely important for airing out the condensation, cooling the coil, and if you are installing a Pertronix module, it too needs cooling. Like someone said, if you choose to ignore sound advice, it's your truck. We usually get several calls per month, people wanting to know why coils keep failing, etc. My first question is always this, is the vent system in place and operable? I generally get 1 of 2 answers; #1, I took all that off because I don't go fording, or #2, they don't have a clue what I'm talking about. I tell them to get the ventilation system operable first, then call me back if the problem continues to persist. Most of the time I never hear anything else; once in a while someone will call back thanking me for helping them fix their issue. Seldom do I get calls back saying that didn't take care of the coil eating issue.
Bringing this back up. I see the Pertronix ignitor has two different models with the same part number, MV-161A. One model is more like a half circle while the other is almost a full circle with 2 nubs on the end. Is the half circle version the correct one for a 52 M37?
tinmedic wrote:Bringing this back up. I see the Pertronix ignitor has two different models with the same part number, MV-161A. One model is more like a half circle while the other is almost a full circle with 2 nubs on the end. Is the half circle version the correct one for a 52 M37?
There is only 1 MV-161A. Obviously 1 of the photos you have seen is not correct. The 1 you describe as full circle with 2 nubs sounds like the MV-161A. I could probably identify the other if I could see a picture.
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