SeasonedNewbie

So, I couldn't stand it... I got a 12 volt internal resistor coil. I also cleaned up the points to give me a chance to at least start the car. Frankly I was expecting it to be the same as before but I was pleasantly surprised. The idle was nice and smooth, I checked the time by the vacuum gauge. Cold, I was hovering just above 15. And it is very cold outside, so I let it warm a bit and tried a drive. Back to normal, plenty of power, no hesitation. After that I had vacuum closer to 20. Obviously it needs good points in it but now I feel more confident that it's not going to burn up the next set. And it seems to minimize the worry about something internal. We're about to get an extreme winter storm here but I need to now change the oil since I've had lots of starting and stopping mixed with crappy combustion. For today, I think we have the answer.

A DeSoto guy did share some pictures with me but only after the dash was away. There are a lot of brackets and braces, the vent, the radio support, the wipers. I think some of the hardware hides behind the windshield trim. I believe it does come out though, and I know the instrument cluster will. How, I couldn't tell you. And getting it all back, oof. Fortunately the Chrysler came with an adjustable front seat and I believe it comes out. I know the floor pan will also unbolt and lift away. I could make a better arrangement for myself in there.

I definitely want to solve the problem before I trash a NOS set of points. It probably isn't an ideal charging rate. I didn't put much trust in it either but putting a battery charger to it, it clicked right to full. I do want to go back to 6 volt positive ground but I really should put all new wiring in. I have yet to find a good set of instructions for how to get the dashboard out. That is my main catch there. I remember once pulling the dipstick and seeing shiny flakes, they pulled that motor. My CFI was fortunately pretty safe when it came to all that. I did however fly with a guy a few times that no doubt put his change in the motor... I remember going in his WWII bi-plane and really wondering what level of work it had seen. No problems but stalls in an open cockpit was enough for me.

Like with so many things, there are numerous opinions on the subject. I don't intend to use the car as a daily driver, so it's ok when it's not in the mood to go. But personally it bugs me. It seems to charge though when I've got the heat and the lights, just not at idle. It's usually hanging right at zero or just below (again, backwards) at speed. I agree, burnt points are the problem to solve. I definitely don't have the right coil, I'm going to get a 12 volt internally resisted one and yet some more points. I will see if I can trace wires and see if I can verify everyone is wired properly. Incidentally, I was working on my pilot license til I couldnt get my medical certificate. I admired those little Cessnas, I spent a lot of time in one.

And that comes back to my original thought, a 12 volt battery that was constantly running low not putting out enough to adequately run that. But now, will it work better that it does charge at speed.

I don't know that much "converting" was actually done. There was a voltage regulator on it of unknown type, one of the little resistors had burned through on the bottom. I replaced it with a 12 volt unit. So it's using the factory generator wired through that. My understanding is that the generator really doesn't care. The battery stays up and I haven't had any issues from that. Except possibly this. It appears to me that the ignition is wired properly.

If there's a ballast resistor between the key and the coil, I haven't seen it. There's 2 wires I believe going into the positive side of the coil (remember it's all backwards) and one wire from the negative headed out to the distributor. Other than that, it's pretty much what it came with.

I didnt do the conversion to 12 volt negative, it was that way when I got it. For one thing and another, flipping it back to positive ground 6 just hasn't been an option yet. But I've accounted for the reversed polarity each step of everything I've done. I just haven't gotten behind the dash to change the amp meter. It's using its original generator to charge, so I don't think the amp meter is getting hit too badly. There's nothing between the battery and the coil, so whatever is going in there is going out the other side.

I might have this figured out. Here's my theory: I wanted to double check my distributor work, so I pulled it again. Burned points. Brand new, new condenser, new cap, new plugs, new rotor, new coil. The points were set to the .020" recommended. Remember, this car got switched to 12 volts at some point. And it's charging system was non-operative. The coil it had when I got it was 6 volt and eventually was cooked. Then, I got a 12 volt coil. It ran, but poorly. So I read about coils and that is a confusing topic with lots of disagreement. But, it ran better with the 6 volt coil, so there I went. It ran great, no trouble. Then ... I fixed the charging system. That was also not too long before there was a problem. I don't know how long, perhaps a couple weeks? The battery charges and it's now supplying the full voltage to the coil. Before, who knows how much it was actually getting. Is it possible that now with the system charging working that it's overwhelming a coil designed for less voltage? The only flaw here is that it took weeks to ruin the last points, mere minutes to ruin these.

I meant to also add that it always starts right away. Even through all of this, it's still basically a bump from the starter and we're off. Maybe a couple cranks flat cold in 30 degree weather. But typically it's an immediate start.

We can rule plugs out. I got new, gapped and installed. It didn't hurt but no significant change. I ran til good and warm, took a drive and it still stumbles and carries on from acceleration. In 3rd it'll start developing a bit of power the way it normally does but then goes totally flat with no more power. Idle is ok, a bit unsteady at times. I suppose next is to test compression and see what's there. Vacuum is starting out at about 15 and slowly finds it's way to about 17 once it's warm. I did notice the exhaust heater flap sort of blows open on acceleration but closes again at idle. I fixed it open, no change.

I haven't yet gotten brave enough for a compression test. However, I did try the tests outlined in the vacuum gauge list. It passed the ring test, behaving exactly as outlined. I'm still inclined to believe it's late timing. I will get new plugs to see. I've also been trusting plug wires that came with the car. They look pretty recent but I know they can really turn things to crap.. though my experience has been they tend to work better cold, worse hot.

For an update, I wish I had better news. I got new points, condenser, ground wires. I assembled everything carefully and got it installed. I believe the advance is operating correctly now but I do want to double check it again before I go further. I cleaned and capped the plugs. I got the car running. Right back to where we were. Bogging down, popping on deceleration. Once you built some speed it smoothed a bit, which does sort of make you think fuel starvation on hard acceleration. It idles ok in and out of gear. It did improve as it warmed up but still wasn't right. I set the timing using the vacuum gauge, I got it just past 15. I'm thinking about going in further, taking the head off and see if there's something there. I'm leaning toward there being a valve issue. There's a bit of wavering in the vacuum reading and I tried the simple test of paper in front of the tailpipe, occasionally it gets sucked back into the tailpipe. There is part of me that wonders if it's worth pulling the engine out and just being done trying to chase a million small things. I've watched a lot of the recommended videos on the subject, I've read quite a bit, it seems like it is a doable project. I feel like the expense quickly mounts. The other road, I guess, is to do an old fashioned ring and valve job. I've seen quite a few people recommend it here. I do understand it isn't the same fix as a proper rebuild. But I do believe with some patience it can add miles before the big job.

Yeah, the plate and everything moves smoothly. The weights needed cleaned and lubed, which I did. The actual shaft in there really didn't seem to have any movement to it, it's more the cam assembly. But I agree, having decent parts inside will at least eliminate quite a few variables. I do think it was intermittently grounding against the case with those crappy wires. Not anymore!