Are you claiming to be an engineer, or are you still a parts counter guy?

I have yet to talk to an engineer who can tell me piston slap is desireable, only that it's acceptable on a racing engine with forged pistons. And as I've stated before, if it's engineered in and not a tolerance issue, how come all my pistons don't slap, instead of only one?

I expect piston slap on my forged motors, but not on one with cast hypereutectic pistons!

But it appears there's no use arguing. We're supposed to just drink the KoolAid fed us by GM and dealer employees.

 

Its quality issues like this why people are buying forien cars and ford and GM are in big trouble. I am a mercedes tech and benz v8 do not have steel or iron liners in their aluminum blocks. The piston rings ride against a aluminum clynder wall. The walls are treated in a way that all the moloucles stand up on end and are actualy harder than steel would be. Its engeneering like this that foren cars are winning. I've seen these engines commonly with 200k and as much as 400k with almost no wear. The AMG motors with renntech kits have 600 or more hp with simply a blower pully change. The piston slap IS a problem reguardless. They should be able to make a strong motor that dosen't sound like crap and beat its self apart. Just imagine how long these engines would last without synthetic oil. My guess would be less than 100k. The build qiality of these cars just **** me off. If it wasen't going to mod it I would of baught something else, forien. I hate getting out of a foren car whare everthing fits well and doesnt squeak or rattle into my c5. When I step in I am welcomed by my creaking cheap plastic center counsil and my rattling door i have to slam (i replaced my rocking stock seats). Then I hope my coloum isn't locked up, and maby my headlight switch will work the first time. I'm glad gm is almost bankrupt. Maby they will finnaly change. As for now I am looking for a forien daily driver. maby a C43 or a WRX or a TL or somthing

 

I am neither. A Parts Manager is my job. And if you took time to talk to people on the forum I am always here to help with build info, parts prices, warranty info, claim history or advise. We have had four different engineers on four different occasions come to our dealership and all four times the same result was agreed upon. It may not be a desirable noise, but it not a noise to be concerned about. It may not be a noise that is engineered to purposely be there, but most of them do make some noise and none of them break because of it. Try finding us some engines that have blown or had to be replaced to back up your concern . I could pull repair orders for vehicles with over 100k and a "piston slap" noise that don't burn oil or lose any performance due to it. So when you find a reason to be concerned about it (besides that it is annoying) then let us know.

 

Just a quick little data point:

My '00 FRC is autocrossed, cruised, road trips, etc., right now 138K+ miles and counting. I run an external oil cooler, track temps don't exceed 250 degrees. I just got back from a 800+ road trip and got 28-30 mpg.

Oil is changed when oil life monitor gets to 0% (usually around 7-8K miles, depending on track days) and analyzed by Blackstone labs. No anomalies in the analysis have been found, and metal counts are nice and low.

Piston slap is evident on cold starts and goes away within the first mile. So, apparently piston slap has given me little or no grief.

Just FYI for those that are not perpetually spun up on this issue.

HTH, and have a good one,
Mike

 

A couple of years ago a friend offered to let me try his 03 with a 6-speed. I had not driven a Corvette since 1984 before that. My first impression was a noisy in-your-face cantankerous handful of a car reminiscent of the racket and ruckus generated by a Sixties muscle car. I decided I had to have one so about a week later I bought the triple black 04 vert I have now. These new Corvettes perform so well who would care about piston noise? My other car is an 06 Caddy STS and I would not be happy hearing the pistons in that one (they're quiet) but I really don't care about piston noise in the Corvette. I can understand hearing one or two pecking away does not sound right in a $50,000 car but I don't think I would call it a defect or a problem. It is more of a nuisance than a real problem. You could take all the pistons out and carefully measure them and the bore diameters and possibly tighten the loosest ones up .001 or so and it would probably quiet them down a lot but it's not really going to bother the engine or adversely affect engine life.

 

You know you are right I have heard noise but none of what you guys are talking about. We have over 400 corvettes in or club and various clus around us. I email this thread to all of then to see if anyone come back telling me of this issue, but you are right I can't disagree with proof. have placed the link on the forum yet? I will forward that too . but thanks for the heads up.

 

This is the typical moaning about a non-problem. Why is this a quality problem? Why is it perceived as poor build quality? Quality is only about one thing. Getting the job done without failing. The damn engine is reliable and many users have over 100K miles on them and they do get the job done. Does it break valve springs and drop valves like the original big blocks did (talk about a monster problem) or blow head gaskets like certain other non-American engines have done? No you can go to the track and run it at WOT for 30 minutes or more at high temps and it just keeps producing power. Why don't you find a real quality issue?

Bill

 

Naw, if that's true, why do manufacturers spend so much money and engineering time on noise dampening? Aesthetics/appearance? Ergonomics?
That's nothin' in today's market. Impressive in 1950.

 

For the money spent, the Corvette is an awesome car... but its not perfect... Everybody can find things that they fault about the car, piston slap is just another one. it is obvious that GM has taken the stand that it is not a defect, and they are not going to pay to "silence" it... So that leaves us with three choices...
1 live with it...
2 sell the car and buy something else...
3 fix it.

i understand that the idea of having to pay a fair chunk of change to fix something is uncomfortable, especially when you believe that it should be a warranty issue. But when you look at the overall picture, If it allows you to enjoy the car more, then why not? People replace ugly wheels, upgrade suspension and brake parts, add HID headlights, and on and on... all for the sake of getting more enjoyment out of the car. Why should an issue like this be any different? GM will fix your car if it goes T.U. during the warranty period, and beyond, if you bought an extended warranty. They have taken the position that the noise is not an indicater of a problem, and the mileage that these noisy engines live to seems to bear that out.

So, for me, if it was my car, and the noise bothered me, I would just fix it.

Life is too short to have to live with compromise, especially when you have the power to change it.

 

Above quote taken out of context.

My "other" car is a 02 DeVille. My first Cadillac, and I LOVE that car. It spoiled me with a quality build and one of the best V8 engines ever made. If GM can build that engine to run quite, perform with more than ample power and pass anything on the road I wish, including gas stations, then why isn't the LSx engine able to idle without knocking?

 

It doesn't bother me. The rest of the car makes so much noise that I really don't care about a little piston noise. I know a little about engines and I know the benefits are not worth the effort. If it bothers you why don't you pull the pistons out and measure them to determine which ones you would like to increase in size a little? I am in the racing business and I am used to listening to noisy pistons. Pistons work better when they make a little noise anyway. Have you considered this? If you only have one or two that make noise then the others are too tight and possibly defective. Your engine is not making the power it could be making. All eight should be making noise. You have six or seven defective pistons IMHO.

Regards, Greg

 

100K is not alout these days. a friend of mine has a 91 corrola with 170k+ on it and its lucky if the oil gets changed once a year, by the cheapest place. Yes ls1's don't burn oil (past the rings) and yes they dont blow up, but if its scraping the piston skirts and cylinder walls their IS a problem. I can tear down a quiet benz motor with the same hp to ci, with 300k on it and no mesurable piston skirt or clyinder wear on it. now why is that? Quality. You should also be able to run ANY new car for 30 min at a race track without any engine problems. The brakes might get to hot though. :o As far as head gaskets, You don't even have to look past GM. Quad 4, Iron Duke in the j-body, and the imfamaus dohc 3.4. All with major head gasket problems. standard 60* v6's alwise have a leaking intake gasket that leaks coolant into the lifter valley, and the old northstars. They had blocks so porous, the oil leaked threw them. Threw the side of the block All I'm saying is that american quality has been slacking for years and americans are catching on. If ford and GM want to stick around they are going to have to step up to the plate.

 

MY motor rattles Just keep test driving until you find one that rattles then buy it, because that one will have more power. If you are interested in performance you should have a loud enough exhaust so you would never notice a little ticking anyway!!!

 

I think i started something here But thats OK I enjoy it
I feel pretty at ease with the so called "problem" with piston slap.
Thanks guys.

 

Now, I consider your report and reports from oil analysis to be a welcome bit of news on this issue for the Doubting Thomases here. The tell-all is in the oil analysis showing low metal content. I would THINK that if the slap was bad enough to be harmful, wouldn't your analysis show hight metal content?

Good feedback!

 

And, GM has, as is evident in the C6. I'm pretty sure they had Ferrari guys help with the design, so they are moving in the right direction. True, they are moving forward, and not backward to address the piston slap. And, if it really is an issue, I think that for reasons you stated previously about other not-so-high-quality parts and fit, I think GM thinks the engines will still outlast our desires to keep the cars.

For example, these cars don't really handle all that well, and they hate bumps. Like you said, interiors start rattling to death over time, and after so long, we get tired of all the clunks and rattles. At the same time, newer, and better designed cars come along, and we go buy those. So, I think GM thinks as long as the motors last "long enough", why bother?

With that said, yep, 100k miles used to be a milestone for American cars. So, now American manufacturers can say, "Look, our engines now last longer than 100k miles, If you want more out of it, you may possibly have to put some work into it. But, we are giving you more bang for your buck nowadays, aren't we?" And, we cannot deny it.

I went to a Benz dealership two nights ago. I looked at several different models that ran $100k! Holy sh|t! That was only for some decent-looking sedans, and OK-looking sports models. And, that wasn't even looking at kick-*** styling and performance. But, the point here is that it obviously costs a LOT of money to make those killer tolerance cars, like you mentioned. A Vette is 1/2 the price, and I guess you get what you pay for.