Piston slap. Class action lawsuit.
Le Mans Master
Joined: Nov 2005
Posts: 6,993
Likes: 25
Tech Contributor
Joined: May 2008
Posts: 3,100
Likes: 17
From: Somers, CT and Clermont, FL
St. Jude Donor '09-'10-'11-'12-'13-'14-'15-'16
Racer
Joined: Mar 2005
Posts: 262
Likes: 3
From: Tempe AZ
Then you should go listen to an original 1970 LT-1 start up. Besides noisy loose forged pistons you get loud clatter of solid lifters.
This is a non-issue except for the nitpickers. If you need quiet pistons when the engine is cold maybe you should consider getting a Buick or a Cadillac. The Corvette is a high performance car and with high performance there are sometimes compromises which must be expected. Tighter piston to wall clearances are quieter during operation but tighter clearances also hurt power due to higher friction.
This is why manufacturers usually specify cast pistons. Cast pistons don't expand as much during warm-up thus can be installed with tighter piston to wall clearance. Cast pistons installed a little looser will be noisy when cold but will make more power. There is a tight window between noise when cold and no noise. You could fix it by replacing with slightly larger pistons but it would be more work than the effort is worth and if you could compare the results on a dyno the engine would make slightly less power afterwards, however, the "quietness" nitpickers probably prefer quiet over power.
This is a non-issue except for the nitpickers. If you need quiet pistons when the engine is cold maybe you should consider getting a Buick or a Cadillac. The Corvette is a high performance car and with high performance there are sometimes compromises which must be expected. Tighter piston to wall clearances are quieter during operation but tighter clearances also hurt power due to higher friction.
This is why manufacturers usually specify cast pistons. Cast pistons don't expand as much during warm-up thus can be installed with tighter piston to wall clearance. Cast pistons installed a little looser will be noisy when cold but will make more power. There is a tight window between noise when cold and no noise. You could fix it by replacing with slightly larger pistons but it would be more work than the effort is worth and if you could compare the results on a dyno the engine would make slightly less power afterwards, however, the "quietness" nitpickers probably prefer quiet over power.
-Jon
Burning Brakes
Joined: Feb 2008
Posts: 949
Likes: 1
From: Tampa fl
St. Jude Donor '14
