VCCA Home Forums TECHNICAL - 1945 AND EARLIER 1929-1932 Egine idle after warm up

Well it seems I have a problem with my 31 Chevy. It starts up great idles great and runs great until it warms up. After it warms up the idle gets ruff . Almost like a missing sound. I have inspected my plugs look good , adjusted the valves, changed distributor cap and rotor. I was having rotor issues prior to the problem developing
The engine still runs cool and I am presently working on adjusting the Carb. It is a agter market carb. I have a rebuilt carter 150 ready to go on. My thinking now is it might be carb related.
Deep inside I fear it might be valve related, If so I guess a pressure test would help? Or could I simply pull a plug wire to see it smoothes out?
Any thoughts???

Shocks

Install the correct carburetor first and then go from there. Also, if you already haven't done so, re gap your AC-C86 or AC-C87 plugs to .040" and bump your timing to 18 degrees. That will pretty much eliminate the "popping" noise at the tail pipe when the engine is warm.

OK thanks JYD.
I will recheck my valves clearances and then this winter I will install the correct carb. I already have my plugs set at .041" points .018 and the timing at 18 degrees. A gentlemen at work said to check for vacuum leaks as well!

Yep, a vacuum leak is also a possibility.