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Author Topic:   mystery knock
posted June 01, 2003 10:40 PM
my buddie has a pure stock 350, stock bottom end with a bit of a cam don't got the specs but it is nothin wild... anyways he has knock but it sounds like it;s in the valve train like a valve hittin a piston or somethin like that... the sound seems to be commin outta the carb you cover the carb and the sound is quietter. any sudgestion before we do a tear down.. where to start to look?

jhon hollomon
posted June 01, 2003 10:42 PM
Are you sure it is'nt a rocker arm out of adjustment?

posted June 01, 2003 11:52 PM
Was the block bored or honed? I had 2 motors that we just honed that had a pretty good ridge at the top and with the new rings they would hit the ridge and make a slight hollow thunking sound....1 was in street motor that i got in a truck with a new i chased it for a while...motor ran fine just had the clunk....the other was a quick toss to gether race motor.....might not be what yours is but worth a shot

rico 08
posted June 02, 2003 01:28 PM
If it's coming from the carb i's suspect a cam going flat.

posted June 02, 2003 06:27 PM
k thanks guy..

the cam seems to make cents cause I think thats the second motor it;s been in and it had a few miles on it to begin with so will look there first

posted June 08, 2003 11:55 PM
spun a bearing was piston hittin head....

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