93camaroLT1

My car is running a bit toward the low side on vaccuum, which I beleive is what is causing it to run excessively rich after a heads/cam swap. I already checked the valve timing and the opti timing which were both dead on to where they should've been. So I figured the next step would be to try and readjust the valves with less preload. I pulled off the covers and got the engine to cylinder 1 TDC and looked found that all the pushrods on cylinder 1 and the other rockers that could adjusted at this time would all spin freely with the rockers where they were. The same happened when I rotated the engine 360 degrees and tryed to spin all the pushrods on cylinder 6 and the other rockers that could be adjusted.. they all spined freely.

SO, this pretty much suggests that the valves are fully closed and the lifters weren't bottomed out. BUT, say I did want to try and run less preload, how would I go about this, because if you think about it at this point the lifters are NOT completely full of oil and up, they have just bled down to where they need to be at this valve adjustment. So, right now if I were to pull off the set screw and turn the valve to zero lash (where the pushrod no longer spins) I would only be tightening the valves being the the pushrod is spining while the rockers are adjusted. IS THERE A WAY TO BACK THE NUT AND SET SCREW OFF THE ROCKERS AND GET THE LIFTERS TO FILL BACK UP SO THAT I COULD APPROPRIATELY ADJUST THE VALVES?

aboatguy

Set them with the engine running. Its easy and LT1s don't make a big mess with the valve covers off like their SBC brethren.

Mike

93camaroLT1

The problem with adjusting them with the engine running is the fact that engine barely runs... it runs to rich that it fouls out all the plugs after every run and about 5 quarts of gasoline blows by the rings in less than 2 minutes of run time and it backfires like all hell as it runs, I had thought for sure that either the distributor or valve timing was off, but apparently they are both dead on from when I just inspected. It also won't idle by itself, you have to try and hold the throttle to where you want it and when it backfires hard, you have to tap the gas to get the rev's back up. No way I could adjust the valves with it running like that..

Any other ways to get the lifters to fill backup once i back the nut up?

slagger

iTrader: (1)

what would happen if preload is to tight?
would performance hurt?

Fire67

iTrader: (3)

Try loosening ALL rockers, then disconect the fuel injectors and turn the motor over by the starter untill you get oil pressure on your gauge. That should pump them up to the top position no problem.