engine problems

[michael]

Hi guys maybe someone can help me out,this is mike BB#18 the last 2 races my motor has been backfiring the first time I had to go in the infield because it just kept popping would not run this week at about the 20th lap same thing only this time it stopped after a few laps and the motor ran fine, when it happened the first time we got it home and I replaced fuel filter, coil,cap and rotor, wires and plugs apparently that's was not the problem because as I stated it happened this week. the running temp has been consistently at 190 degrees if anyone has any thoughts on this I'd love to hear them.

Thanks in advance Mike

[Tracy87BB]

You could start by checking the timing and the advance on your distributor. Could also be a valve problem (or a list of other possibilities), but I think that's probably one of the easiest places to start before you go spending a lot of $$$ and changing things that might not be the cause of the problem at all. Just a thought...

[art11758]

If you are running a GM HEI unit try swapping in a module from a running vehicle. (no cost there) The modules rarely go bad, but when they do I don't know any other way of diagnosing them. Popping or snapping thru the carb or out the exhaust is typically a timing problem though as Tracy mentioned. Check the advance weights and make sure all the parts are there. Lost springs within the mechanism will wreak havoc.

[IDRIVEALARGECAR]

also you could have water in the fuel tank or some condensation of some sort due to the recent high humidity and moisture we have all been enduring so it can be a number of things Joey C.

[DAN D.]

weak valve spring? weak/collapsed lifter? cam lobe worn? isolate which cylinder? do a compression test? or a cylinder leak down test(bent / burnt valve?) that may spin in its seat and get a good seat some times? ask rich johnson he is THE MAN!! any water loss?

[michael]

thanks for some of the ideas it might be guys

and yes Dan i am losing some water not a but a few inches whats your thoughts on that.

thanks again if theres more or anyone else agrees i'd love to here them, no racing this week so i have a little time to go deeper if need be

[DAN D.]

no white smoke that dissipates from the exhaust? how did the plugs burn when you took them out? any light colored ones? I know that you said no high temp running, but I would say a sticky valve. Throw some marvel mystery down the carb while at 1,000 rpm or so. Seems like a sticky valve?????