Thread: Just wondering

Tweet

So I just got my big block chevy running in my '69 el camino, and I was just wondering what happens when you flatten cam lobes? I don't think it happened but I was just curious.

Also, I think I probably blew out the powervalves in my Holley. Had a couple of good backfires on initial startup, what does that effect? Just topend performance right?

round cam lobes dont move valves = bad miss and loud clicking sound . blown power valves = much flooding and bad gas mileage

Hmmm, well I did have a little bit of misfiring but I didn't have it timed quite right. Just did it by ear so I could get it going. And I have solid lifters, the loud clicking would be louder than the noise of the lifters right?

initial startup missfire is not a great concern .. run it till it warms up .. check valve lash again .. modern holley carbs are supposed to be drilled in some way to prevent power valve blowout ... it`s been a long time ( 30 years ) since iv`e worked on a big block chevy .. others will give advice soon perhaps ..

Originally Posted by 69elko

So I just got my big block chevy running in my '69 el camino, and I was just wondering what happens when you flatten cam lobes? I don't think it happened but I was just curious.

Also, I think I probably blew out the powervalves in my Holley. Had a couple of good backfires on initial startup, what does that effect? Just topend performance right?

If it pops out the carb or the intake or both you have flat lobes.

Most of the cars that I have seen with blown power valves won't start. Flooding likely the reason. Probably not a blown power valve if you got it started, although I could be wrong and usually am.

Hey 69 Elko, If you flatten cam lopes your valves are not going to open all the way. Pull your valve covers, disconnect the power lead going to the distributor and have someone turn over the engine using the ignition switch. You should be able to see if any of the rocker arms are not acting the same as the others. The power valve replacement in a Holley is not complicated and pretty cheap.
peace Bud