SeasonedNewbie Posted Friday at 01:33 AM Author Report Posted Friday at 01:33 AM (edited) 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. Edited Friday at 01:34 AM by SeasonedNewbie Quote
greg g Posted Friday at 02:30 PM Report Posted Friday at 02:30 PM I haven't gone through all the responses, but it haven't been suggested yet, you might want to do a vacuum gauge timing procedure. Second Chance garagehas a good how to on this technique. This uses intake manifold to find the optimum spot for your car's operating conditions. You did mention you corrected some issues inside the distributor . There is a wire connecting the points to the breaker plate. This is a snort many stranded flexible that allows the breaker to rotate freely from centrifugal and vacuum inputs. Many folks have found that wire in bad condition, insulation missing, broken strands, and or replaced by wire that is too thick to be as flexible as needed. Napa supposedly has replacements of various lengths. 2 Quote
SeasonedNewbie Posted Friday at 02:40 PM Author Report Posted Friday at 02:40 PM 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. Quote
FarmerJon Posted Saturday at 12:01 PM Report Posted Saturday at 12:01 PM It is almost easier to pull the whole distributor, than to install points with it in the car. The distributor drive is a tab, so you cannot get it "one tooth off", just right or 180* out. Once out you can get a better idea of whats going on. I would check that the advance plate can freely move, and that your vacuum advance isn't leaking. Quote
SeasonedNewbie Posted Saturday at 03:07 PM Author Report Posted Saturday at 03:07 PM (edited) 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 Edited Saturday at 03:09 PM by SeasonedNewbie Quote
SeasonedNewbie Posted Saturday at 11:51 PM Author Report Posted Saturday at 11:51 PM 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. Quote
bacelaw Posted Sunday at 12:25 AM Report Posted Sunday at 12:25 AM 31 minutes ago, SeasonedNewbie said: 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. What is your idle rpm? You should be able to idle her down to 600rpms or less no problem. You may want to revisit vacuum leaks. The idle screw should change rpms with very little movement of the screw- unless you have vacuum leaks at the carb throttle plate arm, at the base of the carb, and/or intake manifold. Quote
SeasonedNewbie Posted Sunday at 12:30 AM Author Report Posted Sunday at 12:30 AM 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. Quote
SeasonedNewbie Posted Sunday at 12:32 AM Author Report Posted Sunday at 12:32 AM The carb cover was in no way flat, I'm working on smoothing it out right now. Quote
Bingster Posted Sunday at 12:50 AM Report Posted Sunday at 12:50 AM After saying I would never rebuild a carb, I rebuilt one just like the one you have. And yes, there looks like a gas leak from the orange streaks. I didn't put any sealant on the gaskets because they didn't recommend it if I had to get back in it for some reason. Before I rebuilt it we did start it for a few seconds. I am hoping to get another chance when the weather gets a tad warmer. The interior of the carb wasn't too bad, but some orifices were rather heavy with crap inside. Had to ream them out. Its as clean as a whistle so I just hope I've adjusted everything correctly. Float, etc. My car is a 47 DeSoto Custom and the body looks the same as yours with the exception of the grille. Would like to see more photos of the interior, etc. Quote
bacelaw Posted Sunday at 12:56 AM Report Posted Sunday at 12:56 AM If you cannot get the idle to adjust down lower than 700, you must have a vacuum leak or the throttle plate isn't closing (or both). Most likely areas are intake manifold gasket, carb base, and the throttle arm inside the carb itself... With no air leaks, she should idle way down under 600 without issue. Quote
SeasonedNewbie Posted Sunday at 01:10 AM Author Report Posted Sunday at 01:10 AM 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. Quote
9 foot box Posted Sunday at 02:33 AM Report Posted Sunday at 02:33 AM I’ve had the holes in the throttle body plugged with carbon before. I tried cleaning it and compressed air, but eventually hot water with a couple tablespoons of citric acid powder in an ultrasonic cleaner freed the blockage. You should have a base gasket like this so the base port gets vacuum from the manifold. You might have to lengthen the linkage that’s connected to the carburetor. Just a couple thoughts on why the idle jet doesn’t respond to adjustment. Rick D. 1 Quote
greg g Posted Sunday at 03:15 PM Report Posted Sunday at 03:15 PM If the throttle doesn't close, the idle circuit isn't in the equation. No amount of adjusting the idleair screw will have any effect. The throttle doesn't need to shut completely, you are actually supposed to use a thin drill bit as a gauge for the setting but unless the main linkage is closing and the float and needle and seat are working you are banging yer head against the wall. Is the linkagefrom the gas pedal allowing full travel of the fiddly parts? Quote
FarmerJon Posted Sunday at 03:19 PM Report Posted Sunday at 03:19 PM 14 hours ago, SeasonedNewbie said: 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. Not sure what make carb you have, but all the ball&balls and the Carter WA-1s I have rebuilt have a faint gap around the throttle plate. Even removing the plate and reseating it only gets them so good. I don't think it makes a difference for a single carb set up, I have no problem achieving a 475 rpm idle (manual transmission, maybe you have a different spec) With these old cars, chances are that it isnt just one thing wrong, it can be a little bit of everything. You can check for intake leaks by spraying carb cleaner at the suspected leaks, and if Idle changes, it is leaking. I would check for air leaks and rebuild the carburetor, then reassess. Quote
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