This is an overstatement and is not true. The only way you can stop piston noise is to fit them up tight. A performance engine does not need tight pistons. Tight pistons are for Toyotas. We won the Daytona 500 this year with piston slap. We build over 600 race engines a year and all have intentional piston slap.

 

He is right there is no piston slap. The noise we hear is the liftersand pushrod chatting as they pump up and perloads are set. That why with GM motors you have to ensure you have oil pressure and get ot operating temp. All of you, really think about it. The lifters bleed down each night or when goe away for extended time and you have to pump then back up. MY $.02

 

So you believe that is the same noise? It's clear you haven't heard a true piston slapping engine and this is what bothers me the most. Evidently, only a few of these LSx engines come off the line sounding like this. IF IT WAS a design feature, then why don't ALL LSx engines display this problem? Why must I have to live with a defective engine?

I have made a new video of my car and it’s knocking, tapping, ticking engine. I’ll work on the edit and post it sometime tonight. Check back for a link, and take a listen for yourself. You can’t argue with the proof.

http://cosmictrucker.googlepages.com/home

The audio clip will work with Windows Media Player, but not by default.

 

So yank the engine and have it built to run quiet like you want...
Whats a few grand in the overall scheme of things?

 

I may end up doing just that! I may even look into dropping in a LS7. At least that engine was built with cast, not forged pistons because??? because GM was finally willing to correct the problem on it's flagship engine. Here is a news blurb on the LS7.

LS7
7.0 L LS7 engine in a 2006 Chevrolet Corvette Z06The LS7 is the latest high-power LS engine. It is a 7.0 L (427.6 ci) unit, based loosely on the LS2. The block is changed, with a larger 4.13 in (104.9 mm) bore and longer 4.00 in (101.6 mm) stroke than the LS2. The small-block's 4.4 in (111.8 mm) bore spacing is retained, requiring pressed-in cylinder liners. The crankshaft, and main bearing caps are forged steel for durability, the connecting rods are titanium, however cast pistons were retained to avoid the piston slap issues that forged pistons have on startup. The two-valve arrangement is retained, though the titanium intake valves have grown to 2.20 in (55.9 mm) and sodium-filled exhaust valves are up to 1.61 in (40.9 mm). Peak output is 505 hp (377 kW) at 6300 rpm and 470 ft·lbf (637 N·m) at 4800 rpm with a 7000 rpm redline.

The LS7 is hand-built by the General Motors Performance Build Center in Wixom, Michigan. Up to 15,000 LS7s will be produced each year starting in 2005. Most of these engines are installed in the Z06, but some are also sold to individuals by GM as a crate engine.

The 7.0 L mark had already been reached by the LS-series of racing engines, famously in the 24 Hours of Le Mans Corvette C5R. GMMG Berger Camaro ZL1s made late in 2002 and GMMG Berger Dick Harrell Camaros (inspired by the Roger Penske Mark Donahue concept car) also featured variations of the 7.0 L size.

Click here to view LS7

 

Also Atascadero, I didn't buy this car to rebuild. I thought I was buying a new car, and one without major defects.

I also noted in your profile this:

Why a Corvette? well, I have never owned one before, and the C5 represents a high standard

I too thought the corvette was built to a high or higher standard. I even took a trip to Bowling Green and toured the manufaturing plant a few summers ago before I bought my car. I was in luv, and nothing was going to spoil that but a knocking, tapping, clicking ticking engine. That's not the high standard I was expecting.

 

If that was true, you would hear crazy lifter noise on initial cold startup. This may happen in some cars, but it's not the noise others concider cold piston slap.

My car is super quiet on initial startup, then about 1 or 2 minutes after startup I can hear some ticking noises (probably piston slap or maybe the valve train is doing something funky during warm-up), which then slowly dissappears over the next 2 or 3 minutes of warm-up. Once warmed up, the engine is relatively quiet but has what I would call normal valve train and injector noises.

When piston slap or excessive valve train noise does not go away after the engine warms up, then there is a definate problem going on. Also, I have seen where guys think it's piston slap after full warm-up, but it turned out the be lifter noise due to installation of a bigger cam, and with time the lifter bodies got worn -- most likey due to the more radical cam profiles.

 

Notice that it says cast pistons were "retained". They all have cast pistons, always have. There's no change there.
The referenced site is correct in stating that forged pistons would be noisier. They have a greater thermal expansion, and need to fit looser.
So since these engines have always used cast pistons, GM has never had any excuse for the noise, especially since it's usually not on all cylinders. If all cylinders made the noise, they could claim that the pistons are deliberately loose .
One way to distinguish between "piston slap" and other noises is that piston slap gets louder under load. You might not hear it at idle, but hear it when first pulling away. Or if you hear it at idle, it would get louder with light load. Valve train noise generally won't change under load.

 

The Corvette is a thrashing machine (except with A4). Perhaps a BMW or Lexus would be more in line with your tastes

 

Regardless of what you think, this noise is normal. It may be a little annoying, but your engine is OK. I have been around these motors since they came out and we have NEVER EVER had to replace one for a "piston slap" related issue. In fact, we have never replaced one in any vehicle that had less than 175K on it. We have had a couple customers who believed this "piston slap" B/S and we had to fly GM engineers out from Detroit to listen to their car. When it is all said and done the customer is happy knowing that it is a normal condition and they are done complaining about it. The engine is not going to fall apart or suddenly "slap" itself to death. Motors in your street machines are not the same thing. Lets not compare "55 small blocks to Gen III motors. Lets compare apples to apples. If you are still not convinced this is not a problem, then you should do exactly what you say and sell your vette anf buy something else. But we all know that you will not do that. If you are willing to sacrifice the performance and handling of a vette to get into something else over a little noise then I feel sorry for you.

 

Actually the STS, Escalade, and XLR all cost significantly more than a standard C6. Hell even a fully loaded Tahoe/Yukon/Suburban cost equally as much as a C6.

 

Like I said, I have heard hundreds of these motors EVERY DAY, many of whom say they have "piston slap" and it is no big deal. The proof is that it is nothing to worry about.

 

You'd lose that bet, my 05 GTO (LS2) has worse slap then my 98 vette!
BTW here's a news flash to all you complainers about piston slap, aluminum has little or no sound deadening properties so guess what your block and heads are made of..........
Oh and I almost forgot, on the older engines the wrist pins were off set to reduce piston slap, causing more internal friction.
Thats not to say that the engine could not be made quiet, it's just not a cost effective requirement.
So if it really bothers you that much go out and buy a car with a cast iron block and heads and be happy!
Frankly I'll keep my noisey LS1 & LS2 and know the next time a "quiet engine" pulls up next to me I can blow it's doors off!

 

Not sure why people are given a hard time for saying the noise shouldn't be there. And the problem doesn't just show up on aluminum engines. GM has had the same problem with iron blocks.
Maybe it's just a noise, but interior rattles, suspension squeeks, a stereo speaker that doesn't work or rattles, or a radio with a lot of static are also just noises, and most people would complain about them too, and they may affect resale value.

Not sure I'll buy the argument that a car with piston slap is necessarily faster than a car without.

 

LOL, thanks for the laugh.

 

Hundreds EVERY DAY? Damn, the problem is worse than I thought.

 

Hundreds in total, but many every day, and THERE IS NO PROBLEM!!!!!

 

Yup, we already know that's GMs position, and that's the dealerships position.

I have an idea!
Maybe GM could consult their customers regarding what's acceptable.

Woops, sorry. Bad idea. Then they'd be like some solvent Japanese company.

 

'Cause they do

The B&M'ing about piston slap on the Ford 4.6 and 5.4L SOHC mod motors is every bit as loud over in the Blue Oval camps as it is here. My wife's current 5.4 '05 F-150 has it, as did my '03 4.6 Mustang GT. Both get/got quiet as soon as they warmed up, consistent with Ford's differential expansion explanation. I still have yet to see any proof of a bona fide mod motor failure due to piston slap.

IMO, what we're all listening to is not some sign of internal combustion doom, but just the reality of today's emissions/fuel economy/power demands: engines today are being deliberately designed with increased clearance and very short-skirted pistons (little more that flat-topped ring holders, in some cases), exchanging the potential for some additional noise for "more" performance, economy, etc.

The key question is whether that extra noise translates into premature wear/failure. The older of us were trained that *any* unusual knocking or banging inside a motor was a baaaad thing. But the real-world experience with the Gen III and Ford mod motors (i.e., extraordinarily reliable) has pretty much confirmed that our "old" knowledge is no longer valid.

 

That is the best way to put it. People used to listening to "old style" motors will think differently then people who have mostly been around Gen III motors. It's like the saying "you can't teach an old dog new tricks" You "old dogs" need to trust the engineers and people who know about these "new style" motors.