Cold start up knock
Thread Starter
Le Mans Master
Joined: Oct 2008
Posts: 8,877
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From: Whitby Ont.
Cold start up knock
Don t know much about the car yet, am still figuring it out. 2002 ZO6, Trickflow heads, roller rockers with trunion kit, long tubes, fast intake ported, ls2 t body ported, vararam cai. When i do a cold start, i hear knock, sometimes i think it is in the back then sometimes it seems near the front on the alternator side. It is not the sewing machine lifter noise that is standard with the LS engines. Oil pressure comes right up immediately to 45lbs or so, knocking goes away in about 3-4 minutes. Not sure what can be, maybe oil leak off from a lifter ? Don t think it would be knocking tho. Any ideas or thoughts would be appreciated.
tia Al
tia Al
Acct Suspended APR 2026 by request
Joined: Dec 2010
Posts: 10,367
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2020 Corvette of the Year Finalist (performance mods)
C5 of Year Winner (performance mods) 2019
sounds like it might be piston slap, the pistons will expand a tad when they get hot hence the knock goes away
