Just being a smart azz. Can't help it sometimes. Run it. mike...
L82, Forged piston "slap"
Thread Starter
Burning Brakes
Joined: Sep 2005
Posts: 1,139
Likes: 109
From: B'ham Alabama
Ok,...so I have come to the realization that the noise is normal and nothing to be of concern. However, I hate it!
How can I remedy this problem?
Do i Just replace the forged pistons with a cast piston? If so, will I lose any of the current power? Will replacing the pistons cause a balance problem? Can I get by with replacing the pistons without a rebore?
Again, it has good power, great compression, no blow by, does not burn ANY oil, great oil pressure,....just noisy .
I don't want to do a complete overhaul if I don't have too,.... But I'dike to quieten it down.
How can I remedy this problem?
Do i Just replace the forged pistons with a cast piston? If so, will I lose any of the current power? Will replacing the pistons cause a balance problem? Can I get by with replacing the pistons without a rebore?
Again, it has good power, great compression, no blow by, does not burn ANY oil, great oil pressure,....just noisy .
I don't want to do a complete overhaul if I don't have too,.... But I'dike to quieten it down.
Thread Starter
Burning Brakes
Joined: Sep 2005
Posts: 1,139
Likes: 109
From: B'ham Alabama
I know I shouldn't worry about it,..but it's SO loud when cold its embarrasing. For example,...I was at a car show cruise in last Saturday. Everyone was admiring my Vette. She stole the show. However, after a couple of hours, I decided to leave and fire it up,...everyone looks in my dirceteion and I had two people come up and ask, "Whats wrong with it"?
She looks like a beautiful sports cars but sounds like a diesel truck.
She looks like a beautiful sports cars but sounds like a diesel truck.
Le Mans Master
Joined: Jan 2006
Posts: 6,506
Likes: 139
From: Butler Pa
I know I shouldn't worry about it,..but it's SO loud when cold its embarrasing. For example,...I was at a car show cruise in last Saturday. Everyone was admiring my Vette. She stole the show. However, after a couple of hours, I decided to leave and fire it up,...everyone looks in my dirceteion and I had two people come up and ask, "Whats wrong with it"?
She looks like a beautiful sports cars but sounds like a diesel truck.
She looks like a beautiful sports cars but sounds like a diesel truck.
Le Mans Master
Joined: Apr 2011
Posts: 6,284
Likes: 1,171
From: Hermosa
Change the oil to something lighter. See what happens. I suspect you are hearing more than piston slap.
The Mobil1 0w40 would make a big difference and it has the required 1000 ppm of zddp that most recommend for flat tappet engines. It is also synthetic, all better for your engine.
If your not ready to make the leap to 0W then try some 5W something oil. Just know that most recommend 1000 ppm minimum of zddp for a flat tappet engine.
If you don't know what zddp (zinc) is do a search here You'll get TONS of opinions on the subject.
Read this it may help with your decision.
http://ferrarichat.com/forum/faq.php...tor_oil_basics
The Mobil1 0w40 would make a big difference and it has the required 1000 ppm of zddp that most recommend for flat tappet engines. It is also synthetic, all better for your engine.
If your not ready to make the leap to 0W then try some 5W something oil. Just know that most recommend 1000 ppm minimum of zddp for a flat tappet engine.
If you don't know what zddp (zinc) is do a search here You'll get TONS of opinions on the subject.
Read this it may help with your decision.
http://ferrarichat.com/forum/faq.php...tor_oil_basics
Melting Slicks
Joined: Mar 2006
Posts: 2,248
Likes: 67
From: Warrington PA
Finalist 2020 C4 of the Year - Unmodified
I know I shouldn't worry about it,..but it's SO loud when cold its embarrasing. For example,...I was at a car show cruise in last Saturday. Everyone was admiring my Vette. She stole the show. However, after a couple of hours, I decided to leave and fire it up,...everyone looks in my dirceteion and I had two people come up and ask, "Whats wrong with it"?
She looks like a beautiful sports cars but sounds like a diesel truck.
She looks like a beautiful sports cars but sounds like a diesel truck.
As mentioned above, just drive and enjoy it, the sound goes away after the engine warms up...again my 75 L82 gave me many trouble free miles with that slap.....have fun........Tom
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Safety Car
Joined: Mar 2007
Posts: 3,652
Likes: 49
From: Bridgewater nj
You can try pulling plug wires one at a time to see if its one piston or multiple.
try a different oil?
maybe a hotter thermostat 200-210*
If it really is a piston slap there really isn't much you can do....
My LQ9 in an SS Silverado had a noticeable slap and it went away after about 60,000 miles. I figure carbon build up quieted it down.
Run it until it blows!!!
then makes sure your tolerances are tight, next time around.
try a different oil?
maybe a hotter thermostat 200-210*
If it really is a piston slap there really isn't much you can do....
My LQ9 in an SS Silverado had a noticeable slap and it went away after about 60,000 miles. I figure carbon build up quieted it down.
Run it until it blows!!!
then makes sure your tolerances are tight, next time around.
Team Owner
Joined: Oct 2004
Posts: 81,241
Likes: 3,063
From: altered state
St. Jude Donor '05
If its any consolation my 383 has slap it can sound mild or sometimes bad depending when cold. It can really make you 
sometimes
By the time shes warm its fine, all about play and listening to the solid valvetrain. Just the way they are
Build em loose quick 50 mi break in and give her hell.
sometimesBy the time shes warm its fine, all about play and listening to the solid valvetrain. Just the way they are
Build em loose quick 50 mi break in and give her hell.
Le Mans Master
Joined: Oct 2002
Posts: 7,098
Likes: 378
From: Las Vegas - Just stop perpetuating myths please.
Oil additives or rebuild - anything in between is not worth the effort.
Heck try some ol'e STP, Lucas oil treatment, RESTORE or the like. U should google this also. Why not just try a new additive at each oil change? What have u to lose?
To replace pistons means a full bore and hone also let alone polish the crank and new brgs - with heads off vlv job to. Now more like $1500.
Good luck with what u choose and if u find something that works please share and post here,
cardo0
Heck try some ol'e STP, Lucas oil treatment, RESTORE or the like. U should google this also. Why not just try a new additive at each oil change? What have u to lose?
To replace pistons means a full bore and hone also let alone polish the crank and new brgs - with heads off vlv job to. Now more like $1500.
Good luck with what u choose and if u find something that works please share and post here,
cardo0
Melting Slicks
Joined: Jul 2009
Posts: 2,091
Likes: 40
try using a high zinc oil and hi test pure gas for a while to see if that helps,
my L82 in the 74 z28 makes no noises like you describe , that's weird , the engine does run a lot better on th premium pure gas . I use Amsoil high zinc content.
good luck
my L82 in the 74 z28 makes no noises like you describe , that's weird , the engine does run a lot better on th premium pure gas . I use Amsoil high zinc content.
good luck
Tech Contributor
Joined: Aug 1999
Posts: 14,380
Likes: 6,391
From: At my Bar drinking and wrenching in Lafayette Colorado
If your "piston slap" is so loud that it's embarrassing on startup, it's probably not piston slap. I run a lot of forged piston engines, and I never have piston slap any louder than the solid lifter cams I run, when the engine is cold. When the engine warms up, real piston slap should go away. Completely. When warm, a forged piston engine should run as quiet as a cast piston engine.
The last time I had a "piston slap" that was loud and did not go away after warm-up, it was actually a floating piston pin that was failing. I'd suggest you pull spark plug wires off one at a time and find which cylinder is the offending cylinder. Then, troubleshoot the real problem. An engine should not knock like that after warm-up unless you have a significant problem.
Lars
The last time I had a "piston slap" that was loud and did not go away after warm-up, it was actually a floating piston pin that was failing. I'd suggest you pull spark plug wires off one at a time and find which cylinder is the offending cylinder. Then, troubleshoot the real problem. An engine should not knock like that after warm-up unless you have a significant problem.
Lars
Le Mans Master
Joined: Jan 2006
Posts: 6,506
Likes: 139
From: Butler Pa
Safety Car
Joined: Mar 2007
Posts: 3,652
Likes: 49
From: Bridgewater nj