highlandautoman

True leadfoot....forged pistons do have some slap till the aluminum expands, but...these are factory cast pistons and are not prone to expansion like forged. thanks ....Mark

highlandautoman

Dear GMF...No, it may not cause alot of problems, ,but try to tell a person that just spent 40k on a sports car that it is supposed to sound like his old chevy winter beater w/ lifters rattling. My customers aren't too happy. I can't say as i blame them, and I promised them that I would do everything that I can to help them correct this problem. Thanks....Mark

highlandautoman

Dear TTopJohn, This noise starts on cold starts only and progressively gets worse. The 3 that I am dealing with now never go away. Sounds like collapsed lifters. Not too appealing for a 40k plus sports car. I have specialized in Corvette repair since 1970 and never have as many complaints as the c5's are getting. I promised my customers that I would do everything that I can to help them out. So....here I am...Thanks....Mark

0vetteshop

Though it can be annoying,the piston slap on the C5 is not a durability issue.The piston slap is simply caused by the "short skirt" piston design utilized in the LS1 and many other high performance applications.Before the piston expands and reaches operating temperature,it tends to rock in the bore due to the short skirt design...It is the nature of the beast :yesnod:
http://www.vetteshop.cc/

highlandautoman

Dear cscollis, I asssure you that I am not a lawyer. I own a repair shop specializing in Corvettes since 1970. I have around 15 customers w/ 97-03 Vettes. They all want answers. And I promised them that I would do everything that I can to help them out. I personally have 3 vettes. a 64, 79 and 93. So, this piston slap really doesnt affect me other than having to explain to my customers why thier 40,000 Corvette sounds like a 75 Caprice that is going to the boneyard....Thanks....Mark

highlandautoman

I would sure love to see that one db....sounds hot....Mark

highlandautoman

Dear Tom....first off I get nothing out of this except happier customers. I own a Corvette repair shop since 1970. I currently have about 15 customers w/c5 vettes. About 4 of the 15 are making this noise. I have spent hours on the phone w/ GM. All they tell me is that GM Doesn't have a noise problem w/ the ls1 vette engines. So get off your high horse and cut me a little slack. I have no stake in this other than trying to cure a problem. And NO...GM wont admit anything. I would like to know who admitted to you that they have a piston slap problem on #7 because I couldnt locate that person .....Mark

davyalabama

I'm not a lawyer - I do care if it affects my car - and I care if it sounds horrible - The marbles-in-a-can sound is bad enough.

clem zahrobsky

i have owned 3 C-5s,97,99 and a 02 without any noise i would consider abnormal in a high performance high RPM engine. piston noise would be at engine speed and lifter noise would be at 1/2 engine speed.:chevy

TCW

Mark please reread my post. It was not directed at you! It was directed at the guy who said lawyers were a scurge on the US. I truely resent that remark!

As for the info about the number 7 pistion, I got that from another Corvette tech who is no longer on this forum. His handle was C4C5Specialist. He's now an active member on another C5 Forum. You may want to go there and get ahold of him.

Tom



[Modified by TCW, 8:58 AM 7/19/2003]

highlandautoman

Sorry Tom if I misread your post....I just have been so aggrevated over this one. I never had this kind of problem w/ so many new Vettes. I was always a GM man. Now I find myself wondering. Told GM customer care that I may have to tell my Vette customers to buy elsewhere.. (GOD I HATE THAT THOUGHT) Just and empty threat. Oh well, thanks for listening....Mark

highlandautoman

Clem this noise starts out at idle and goes away after about 1 min of running at first. As the vehicle reaches around 45 to 50k miles....the noise is at idle, and increases like a rod knock under acceleration, never going away. I hope you have better luck w/ yours....Mark :cheers:

highlandautoman

Davy...good news is that it is fixable...unfortunately not under warranty. If we get anywhere w/ GM I will post it here. Thanks....Mark :)

Hib Halverson

For the most part, I think this thread is bogus.

Yeah, the Gen 3s have a cold piston knock problem prior to MY02 engines, but for the most part, the noise either goes away once the engine warms or, if it remains, you can barely hear it.

C5 TECH has it right: in most cases cold piston knock is not a durability problem, it's a pleasebility problem for **** C5ers.

For MY02 GM made two changes in LS1/6 engines to address the cold piston knock. 1) the block machining process was changed slightly to make a small reduction in piston-to-bore clearance. In order to prevent piston scuffing with the tighter piston-to-bore clearance when the engine gets really hot, the piston skirts are now coated with a polymer antifriction coating.

For my money, If I owned a 97-01, and it had cold piston knock, I'd leave the engine alone as there is a small performance gain with looser piston-to-bore clearance. If you want to learn some more of the facts surrounding this issue, see http://www.idavette.net/hib/02ls6/page5.htm

This thread is loaded with posts by highlandautoman and in just about every one, he claims to be a service tech who's owned a Corvette repair business since 1970. I think, if I were going to consider hilandautoman's campaign to start a class-action against GM over cold piston knock, I'd first be asking about that person's credibility. What's the name of this Corvette Shop? Where's it located. Has it really existed for 33 years? What's highlandautoman's real name. What's his experience and training working on Gen 3s? Does it do sublet warranty work on Corvettes for GM dealers?

w8d4it

I also resent remarks about attorneys like the one made by the "gentleman" from Frisco. After 15 years of practicing I'm used to it. Funny thing is that when a guy like that is in trouble (either civil or criminal) a lawyer is his best friend. Some colleagues can't count the number of disturbed nights from clients in jail or on a crying jag from going through a divorce.

highlandautoman

Dear Hib, Thinking this thread is bogus is your opinion. Your are asking about credibility. My name is Mark A. Owen. My shop name is Highland Automotive. 122 West Market St. Akron, Ohio 44303. 330-253-3664. 330-253-1951 (fax) The shop was originally opened in 1970 as Highland Square Mobil at 867 West Market st. 1st closed the gas station then moved from the area called Highland Square. I personally started working for Highland Square Mobil in 1977. I purchased the business from the original owner Ron Frame in 1996. We have done some sublet repairs for our local Chevy dealers..(mostley rear wheel bearings on 82 down Vettes) because the dealers in this area cant make them last. So yes, I do know a little about Corvettes. Like I said, I am only trying to help my customers and anyone else who is interested. These C5's I am dealing with, the noise NEVER goes away, and is MUCH worse under acceleration. Nobody can say that this problem isnt going to cause more problems. Not even C5-Tech. If I offended anyone in some way....Sorry...Mark


[Modified by highlandautoman, 4:19 PM 7/20/2003]

highlandautoman

Please read above thread in response to Hib

RHILL

Me too :iagree:

blacksn95

Can't argue w/ you there ;)

wwashing

I really don't see how you or anyone can say it's "pleasebility problem for **** C5ers". :confused: This sounds like the responsible party trying to spin the issue away from the real issue.

I think these vehicles are seriously devalued. The day I go to sell my car with piston slap, I think I've got a major problem convincing a potential buyer not to worry about. I know I'd walk away from such a vehicle.

And, I'm very positive that any dealer that's going to consider one as a trade in will certainly not fail to use the issue to mark down the value of the car.

If Chevrolet is so sure there are no long term duribility issues surrounding slapping pistons, if they offerred a life time warrantee for it, I'm sure everybody would shut up about it. :cheers: