could this be??
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Registered User
Joined: Dec 2002
Posts: 1,810
From: Indiana
could this be??
well, as you know i've been struggling with this motor forever now. after running several tests and trial and error this is what i have found so far. 1) The clacking noise is beating at the same pulse as the timing light, meaning its on the same beat as the cam. this translates into a 95% top end probability. (i don't think i worded that right, but i read it in the "overhauling a small block chevy" book under the diagnosis). it makes sense though. 2) it's not the lfiters, as they have been changed back to stock and the noise is still present. 3) not valve adjustment... done it 100 times correctly. 4) pushrods are not too short 5) piston to valve clearance should not be an issue plus it would have bent half the valves by now or put a hole in my pistons. 6) rockers are not hitting the valve cover 7) oiling system is at full go and everything is recieving lubricarion on the top end. 8) when putting a screw driver on the rockers and intake plenum (listening into handle with ear) the noise was the same, but louder when listen into the intake. this leads me to believe it's in the lifter valley...
btw, i also performed a rod knock test with the removing the spark plug wire and got no changes.
now, i have a wild question here. after really thinking, and doing a mach up on the motor i pulled out, could the lift of the cam be pushing the lifter up so far that it is hitting those retainers that keep the lifters from turning? the lifter has a ledge on it to stop travel, and i wonder if it is hitting that. that would explain lack of noise change through every valve adjustment. i could have sworn i heard some kind of binding when i first put the motor together turning it over by hand. i didn't think much of it then, but it could have been the spyder retainer binding if the lifter was pushing that retainer up. its a wild idea, but i think that would explain my results. has this ever happened and is this even possible? I've changed and tampered everything else. still nothing to prove. if this is the case, how could i fix it? fab up my own retainers? thanks
btw, i also performed a rod knock test with the removing the spark plug wire and got no changes.
now, i have a wild question here. after really thinking, and doing a mach up on the motor i pulled out, could the lift of the cam be pushing the lifter up so far that it is hitting those retainers that keep the lifters from turning? the lifter has a ledge on it to stop travel, and i wonder if it is hitting that. that would explain lack of noise change through every valve adjustment. i could have sworn i heard some kind of binding when i first put the motor together turning it over by hand. i didn't think much of it then, but it could have been the spyder retainer binding if the lifter was pushing that retainer up. its a wild idea, but i think that would explain my results. has this ever happened and is this even possible? I've changed and tampered everything else. still nothing to prove. if this is the case, how could i fix it? fab up my own retainers? thanks