Re: Pinging Problem
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I would want to establish TDC with certainty. Timing marks on dampers can shift. The position of the vacuum advance can vary somewhat, and it is not a reliable guide for timing. The distributor responds to engine speed and load, and it may be over-advancing the spark due to issues with the mechanical advance or a vacuum advance that is out of adjustment or improperly connected at the manifold end, or a stuck advance plate. Improper timing is the commonest cause of pinging, with an overly lean mixture being second. Older carburetors have mechanically operated metering rods. Newer ones may have metering rods operated by a vacuum piston and they have been known to stick.
Point gap affects timing.
Posted on: Yesterday 20:12
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Re: Pinging Problem
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53Cavalier, thanks again for your questions. What happened was that I hadn't been happy with the idle for several years but it wasn't bad enough to chase after. One day in October it suddenly wouldn't idle at all, stalled the instant I took my foot off the gas pedal. That had to be something in the carb idle circuit so I had the carb overhauled. I put it back on and it would idle but it was about the same as it was before. I decided to go after it. I checked for vacuum leaks that could be causing it to run lean, couldn't find any but the vacuum advance might have a pinhole so I replaced that. The advance Max sent was identical to the old one. I R&Rd the distributor to replace the advance and didn't see any evidence of worn bushings. After this is when I noticed the pinging. I had been thinking of putting a Pertronix system in for a couple of years so I did that, their Ignitor II module and the Flamethrower coil they recommend for the Ignitor II. The engine does start a lot faster than it did before but it still pinged. I contacted their technical support and they said there was no adjustment that could be made, look for a cause outside of their module. That's when I found that backing off the distributor position will stop the pinging but the idle quality and the vacuum gauge reading suffer. As to a problem with the mechanical advance, if the weights were stuck in the full advance position wouldn't the pinging happen all the time and not just when under load? I agree that this most likely is a timing problem and I just need to find that sweet spot where the pinging stops and the idle is smoother.
Posted on: Yesterday 22:20
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Don Shields
1933 Eight Model 1002 Seven Passenger Sedan 1954 Convertible |
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Re: Pinging Problem
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56Clippers, thanks for that question. I don't have an exhaust gas analyzer so this hasn't been done. I can say that I don't see any smoke coming out of the tailpipe.
Posted on: Yesterday 22:26
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Don Shields
1933 Eight Model 1002 Seven Passenger Sedan 1954 Convertible |
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Re: Pinging Problem
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Thanks, Ernie for your suggestions. Maybe I should check other manufacturers to see if they make a colder plug. I've watched Ross's video several times on timing the '51 through '54 eights. Since I have no pointer I used his trick of putting a coin over #1 spark plug hole when cranking the engine. He said to use a penny but I found that that jumps every time the piston is on the upswing. A nickel worked better for me, it would move a little whenever the piston was coming up, but when it was on the compression stroke the nickel would flip up a couple of inches into the air. When this happened the rotor was right at the #1 terminal on the cap. So I'm confident timing is close even without the pointer.
Posted on: Yesterday 22:46
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Don Shields
1933 Eight Model 1002 Seven Passenger Sedan 1954 Convertible |
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Re: Pinging Problem
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Thanks, 53 Cavalier for your further comments. The missing pointer is certainly an annoyance. I looked into these pointers. I thought maybe I could make one out of a piece of wire that would loop around the timing cover bolt, but looking at pictures of them the actual pointer is offset from where it fastens to the bolt. A further complication is I can't even see or reach the bolt that it fastens to. It looks like at least the radiator would have to come out as well as the auxiliary pusher cooling fan that I installed in front of the radiator and who knows what else, just to put the pointer on. That's a can of worms I'd rather not open if there's another way to do it.
Posted on: Yesterday 23:03
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Don Shields
1933 Eight Model 1002 Seven Passenger Sedan 1954 Convertible |
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Re: Pinging Problem
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Maybe you can figure out another way to do a temp pointer. I can understand not wanting to pull your car apart to put a pointer on! I'll have a look at my car tomorrow, you should be able to rig something up. My thought is still that checking the timing with a light is a good/important next step.
Posted on: Today 0:44
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