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!

I took time to disassemble the distributor down to the weights and it was an interesting time had by all. I did note a tiny amount of side to side play in the shaft, as described, some change but it's snug, not loose. I discovered how bad the wires in there were so Ive ordered replacements for them. The springs under the breaker plate looked good and do bring the weights back to center. However everything was dirty and not moving freely. I cleaned it all up and got everything moving smoothly there. I'll update once everything is back together. I did get some pictures of the guts though.

Alright, I've had some time to play around and I think there's a wobble in the distributor shaft. I removed it to reset points and then reinstalled, using a dwell meter to adjust points. That figure isn't constant, varying wildly from single digits well into the 40s. It's a digital multi function meter with the timing light. There is currently a 12 volt battery in there and I had it set to the proper number of cylinders, so I feel fairly confident in the accuracy of the meter. But perhaps there's some trick I don't know? I'm also wondering, it has a significant amount of advance as it's currently set. Is it theoretically possible to set the timing so far ahead that it actually throws off the firing order? I doubt that's the issue but I'm curious. I am going to go back to basics and reset everything one more time to make sure I didn't miss something.

The throttle plate definitely isn't sealing up. I was able to back off the throttle set screw and get it much closer but there's still a faint gap around it. As for the intake manifold, I'm not sure but I wouldn't be surprised. I will smooth the area where the carb bolts on before I reassemble it.

The carb cover was in no way flat, I'm working on smoothing it out right now.

When I have the timing light on it (the digital kind) it shows right at 700. I can then idle comfortably in gear which I think takes it down to just under 500.

I was back to rough running today and noticed again the carb was wet. I took it off the car and opened it up. The inside is pretty clean, there's a bit of sediment at the bottom of the float chamber. I'm not sure of the quality of this carb.... I think the float is wrong, it's above the top surface of the float chamber, and I suppose it wants 5/64" to be the gap there. I'm going to lower it. I have read that 1/8" suits the quality of modern fuel to what was used when the book was printed, any truth in that? Also, the idle jet orifice looks like it's off center with the threaded part. I tried to get a picture but it's doesn't show well the angle of the threads in relation to the hole inside. But it isn't straight through. The idle screw doesn't do much to actually adjust the idle. I can run it all the way down and the engine continues to run. And, there's a gap between the throttle plate and the throat. Does it need this for the sake of getting air in there, or is it a sign of wear? The throttle arm also doesn't want to come all the way back to rest against the set screw on its own.

I did pull the distributor, I've gotten pretty comfortable with that procedure. I did change the major setting to give myself more advance at the other setting but I feel like it will tolerate more before there's knocking. The mechanical advance seems to be working though the vacuum advance is disconnected, there's a hole in the line. And I think maybe the vacuum pot could be leaking. I read though the vacuum advance is more of an efficiency tool. I will run a new line though

I used the vacuum method to set the time, it's the easiest way I've found. At the moment, it still acts like the dwell keeps changing. It might be time to totally disassemble the distributor and see what's up. I will check out Napa to see about the wire, it could do with better.

Just to give an update, and to say how much I appreciate you guys arriving with advice. It was definitely points. A badly repaired wire adjacent to the points got them snagged. Everything is cleaned up, routed properly and happily ticking. I found the best gap setting was done with a dwell meter. I'm at 37 degrees which I believe is in spec. (Actually toward the high end, I may try for less) One other question, how far to one side do you guys have the timing setting under the distributor body, the major adjustment? I shifted mine away from center to allow more advance at the adjustment control arm. I used a vacuum gauge to set the timing that way. I feel like it would tolerate more but i can't get to the major adjuster with the distributor in place.

I have never had good luck doing carbs. I know it's a useful skill but I haven't acquired it. And I've heard a lot of people not getting the parts they need with the kits. I had the air cleaner off while I was working under there. And it does need cleaned. I've used the choke a few different ways, and it seems to like to have it off in the first couple of minutes. I've done that, going til it seems to want less and it completely fouled the plugs. I've read to pull it out, stomp the gas, and hold that half way then crank. It always starts and then I push the choke back in til it smooths. Then it's the rest of the way in shortly after that. The sisson choke is there but the wire is frayed off. I havent run a new wire or tested the function of it. I can't decide if it's known to not work and that's why the PO ran the mechanical one or they were too lazy to figure it out. The last guy really did some dumb things. I do dumb things too but usually on my way to getting it right.