big block chevy knocking when cold
11-24-2009, 10:07 AM
#12
Senior Member
EXPERT BUILDER
Join Date: Nov 2009
Posts: 267
When was the last time you adjusted your lifter rocker arms? If they are hydraulic lifters, as the cam wears the lash gets greater until they will start ticking away when cold. If the noise is up high it could be rocker arm lash slap. It is the easiest and simplest thing to check first. Just a 1/4 turn in of each rocker nut will tighen up your hydraulic lash to within specs. If solid lifters you should be checking them at regular intervals anyway...
11-29-2009, 04:54 AM
#15
Senior Member
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Join Date: Jul 2006
Posts: 184
I would also say piston slap, If you have bearing problems, at idle, you would have 0 oil pressure, that would go up a little as you revved it, and the knocking would be proggressivley getting louder and louder the longer you kept driving it like that, and, it wouldn;t go away when it warmed up. Years ago, I has a 350 that would do that. Stock, who knows how many miles, I bought it as a runner, put a cam in it, intake, carb etc, and BEAT the snot out of it. For 3 years it did the same thing. Every morning, knock for about 2 minutes, and go away.
Frank
Frank
