hey all, i've had my new engine for a while and it's been making a knock sound since it's been built. it's only when the engine is under normal operating temps. at about the second hash on the temp guage it's fine. it's only on the right side of the engine.

my engine builder says it's normal, that he had to take an extra .001 out of the bore for "piston expansion" i've never heard of this and didnt believe him, but then i heard it again. i did some research and found the extra .001 is only for forged pistons and older engines...not newer engines.

block is stock LT1, .030 over-bore, +.25" on the crank (forged), Hypereutectic pistons from keith black, and forged rods on a 6.0 length. heads are stock with stock style springs and a CC306 cam, stock replacement lifters, stock rockers, stock pushrods.

much appreciated...thanks for any help.

 

Well, if he "opened up the bore" past the spect for the hyper-u-crap-tic pistons ya may have some piston slap.
If it is doing it at normal temp then it ain't going away(most knock when stone cold). It isn't going to hurt anything if it's light and if ya are running a 160 thermostat go to a 195 and see if that helps.