big block chevy knocking when cold
#3
Senior Member
RACING JUNKIE
Join Date: May 2006
Posts: 2,044
Originally Posted by DrivingMissDD
Sounds like a case of major case of piston slap....
Case of beer maybe....lol
Is the knocking noise down low or towards the top?
What is the oil pressure? > hot?
Usually a rod or bearing noise will get worse when hot.
They way you described it, it kinda sounds like a lifter taking it's sweet time priming up.
A piston slap will sound similar, after a few minutes of driving they'll heat up and expand which quietens them down, either problem is no biggie, drive it till the wheels fall off I say.
What type of oil filter you using?
El~ cheapo filters like a "FRAM" the anti drain back valve never works, try a wix, napa brand or purolater.
The 'good' filters will hold some residual pressure and stay full after you shut the motor off - when you start it up (cold) the motor wont do all that klinking and clattering till the oil pressure builds up.
Something to think about.
Goodluck, Cp
#5
Originally Posted by cepx111
Originally Posted by DrivingMissDD
Sounds like a case of major case of piston slap....
Case of beer maybe....lol
#7
#10
Senior Member
RACING JUNKIE
Join Date: Dec 2004
Location: austin texas
Posts: 729
I have a street driven engine thats a little loose on the crank, When its cold outside it knocks about 3-4 times when it first starts up.... i use to worry about it, but after it got 75,000 miles i quit.