QuestionHoward,I have a 1965 sprite that has what appears to be a ping when the gas pedal is applied. Shifting through the gears will not cause the problem. It happens mostly in 4th gear when a increase in speed is needed. Not at highway speeds but at city street speeds. I adjusted the valves and timing to specs and replaced the vaccume advace unit with out any help. I also tried retarding the timing using the distributor knurl nut a bit with no help. It has the original distributor installed.
Thanks Al
AnswerHi Al,
Pinging under acceleration is a sign of detonation which is destructive to the engine. It can be caused by several things like, Ignition timing too far advanced, low octane fuel, Old stale gas, carburetors set too lean, Engine over heating, Spark plug heat range too hot, Carbon build up in the combustion chambers, head gasket protruding into the combustion chamber, an intake manifold leak or any combination of these.
First thing to do is be sure you have ONLY high octane gas in the car and set the ignition timing to specs. Then look at the condition of the spark plugs as to color and heat range number. Note the engine temp when running and the oil pressure. Then check the mixture of the carburetors by lifting the spring loaded pin under the lip of the top pots and adjust if you don't get the correct response.
Don't skip anything by assuming it is ok. Then after each and EVERY one of these item are correct and you suspect carbon build up you can decarbon the combustion chamber using the water method since the car does not have a CAT.
You say it mainly happens in city traffic in 4th gear. You know that you must never apply throttle in 4th gear when you are below 2000 RPM?
I hope this helps, let me know.
Howard
