Overheating probs

[jlaird]

I just wonder if the advance curve on your distributor is incorrect, for a number of reasons. that would cause overheating. Maybe someone can step up and verify my thought process or shoot me down.

Just came to me out of the blue. Old brain disease.

 

[Guest]

I didn't know my car was running hot. layful:

 

[SaxMan]

My car starting showing signs of running hot after it had been driven 30 to 40 miles on warm days. This happened even after the water pump replacement and chasing down every leak. I decided to retorque the head bolts. That made the problem go away. Of course, I just did the head gasket this past winter, so some retorquing would be expected.

 

[Billm]

Jack
More than anything you need to verify that the advance is 30 to 32 BTDC at 3000RPM, the idle setting will take care of itself (should be about 15 BTDC)
BillM

 

[jlaird]

Hay Bill and all, Miss Agatha does not run hot ever, even when 100 degrees out. Was just a thought by me yesterday which the more I think of it perhaps has some validity. Not to say other things could not effect the prob as well, but so many over the years have professed to have tried everything else,,,,,,so.

 

[John Kuzman]

Hi Jack -

Hope all is well with Kay and you. I have an "old timer" engine machinist/tuner friend who openly tells you that he "ain't no college kid", but I asked him this same question, and he had his grandson dictate his response. Take it for what it is worth:

Retarded will overheat it most quickly. The burn occurs over about 80 degrees of crank rotation, when started late, there isn't time for the the flame temps to be reduced by work against the crank. This combined with the combustion still occurring when the exhaust valve opens ends up dumping really hot gases into the exhaust passages. This greatly increases the valve temp and the amount of heat picked up by the cooling system through the head itself and exhaust port. The exhaust manifold also becomes very hot. With retarded timing, the temps come up very quickly.
Too much advance could cause overheating but it's much slower to build compared to retarded timing. Usually before anything bad happens you usually notice that the engine is hard to start, tends to burp through the carb, and if it runs at all it's with no power. You usually head this problem off before the temps get very high.

Again, for what it is worth....

 

[jlaird]

Oh, lovely John.

Ok all you guys with A 40 engines that overheat. Send you Distributor off to Advanced Distributors to be recurved. I'm sure there are other places but he did Miss Agathas and was a large improvement in runnability.