| carcrazy | -- 09-08-2019 @ 7:27 AM |
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Recently a friend of mine bought a restored 1946 Coupe that has had problems as long as he has owned it. The first stated problem was that the car would start and run fine when it was cold but that once it was warmed up and shut off it wouldn't restart until after it had cooled down. Over the past year many things have been tried to fix the problem to no avail. An electronic ignition system was installed, several new coils, and a new ignition resistor. The car still has a 6 volt positive ground electrical system. A compression check revealed about 75 PSI in each cylinder. Manifold vacuum at idle is 17 in. hg. and steady. The exhaust sound has an unusual "bark". Since this is an unknown engine, it is possible that the cam has either been installed out of time or an aftermarket cam with too much overlap has been installed during the rebuild. Assuming the stock cam has simply been installed retarded, how much of a job is it to remove the cam drive gear and reset cam timing to the correct position? Please advise. Thank you.
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| TomO | -- 09-08-2019 @ 8:41 AM |
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I doubt that the cam is out of time, but it can be checked by removing the distributor and the timing gear cover. If it is a bolt on timing gear, you can remove the gear and turn the cam and re-install the gear so that the timing marks line up. The crank gear can also be removed enough to change the timing by one or more teeth, but the gear is usually very hard to remove. The car has all of the symptoms of leaking carburetor. When the engine is shut off, the fuel leaks from the carburetor and floods the engine. By the time that the engine has cooled off, enough fuel has evaporated so the engine starts again. The bark in the exhaust could be from a rich mixture. There are two ways to check this out, the first is to floor the accelerator pedal when it won't start. If it starts after a short cranking, the engine was flooded. The other and more reliable test is to remove the carburetor, fill the bowl enough to cover the power valve stem and leave it sit over night. The top of the stem should be still covered the next morning. The fix is to send the carburetor to Charlie Schwendler in NY for rebuilding. Next, I would remove the electronic ignition and install a correctly timed stock distributor. This would give the car a better reliability chance and make it easier to repair when ignition problems occur. Electronic distributors are prone to sudden failure due to electronic "noise" or random voltage spikes in these cars. The newer cars have more ways to isolate and eliminate these spikes. Your vacuum readings are in line with the compression readings. The compression readings are low. Did you take them with a warm engine, all of the plugs removed and the throttle pulled all of the way out with the choke open? I would do them again, if you did not follow all of the above conditions and then squirt some oil in each cylinder before checking the compression again. This will tell you if the rings are worn. Tom This message was edited by TomO on 9-8-19 @ 8:53 AM
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| carcrazy | -- 09-08-2019 @ 12:06 PM |
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Tom, Thank you. I will forward this information to my friend.
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