so how many here have and are still having to deal with that dreaded cold knocking sound when the fire up thwe vette?.....i have looked at the tsb's and gm says it's "normal"...haha...who else has this same problem and is there any correction other than pistons???

 

There is a sound clip on this site - that what you're hearing?

 

oh yeah thats it no doubt...piston slap till it gets hot and makes the piston grow then it's quiet as a church mouse

 

I have it - on my 2000 vert MNT6 - has around 50K miles.

Not sure what if anything we can do about it?

 

I have a 2000 coupe with 25K on it. I wont go through all the country fertilizer that I have gone through with this as GM calls it "normal " condition. Take a look at www.pistonslap.com it does a great job of offering solutions and ideas including the sound clip.

Mine is a bit unusual though. I put in a remote starter so that I dont chill the seat of my pants in the morning. The vette starts and it takes about 20 seconds for the racket to begin but interestingly enough the noise will continue until I get in the car and goose the throttle. The DIC had a coolent temp of 165 and it was still making the noise. As soon as I goosed the throttle .. just revved it up ;and let it back .. the noise immediately went away. I wonder if others do the same.

at this point .... I dont know what to do next .. my dealer has wanted to do everything from an oil change to 10w-50 mobil 1 .. I use 5w now to some additive to dump in the crankcase .. run it 20 minutes .. let it sit 2 hours ... run again and drain and clean. .this is supposed to reduce the carbon deposit and lessen the noise .. all this GM calls routine maintenance and I bear the cost ... I notice no diff in the car in any way except the noise ... I love the car .. but I dont expect this in a 50 thousand dollar car.

The following was posted on pistonslap.com
A free study is currently underway in regards to
the piston slap noise. To become a part of this study please contact Ann Mandt at 1-800-247-5974

Here is an interesting article as well:
http://www.detnews.com/2004/autosins...b01-262757.htm

We all have to join together to force GM to replace the engines or buy back the vehicles. This link has some suggestions on what you can do to help http://www.pistonslap.com/help.htm

 

To begin the positive replys here: I have no noises at all eminating from my LS1 in the morning or any other time. 1999 Hardtop @44k miles.

 

I eliminated the noise in my '04 LS1 simply by switching to a higher flowing oil filter, the Baldwin B31.

 

My 2003 Vette with the LS1 makes a whole bunch less noise than my 97 Camaro Z-28 with a LT1. Both cars are daily drivers. More miles on the Z-28(I sold it) than the Vette, since I retired last year. Both where garaged in a heated garage so the morning start up was fine. The afternoon when it was cold the knocking started in the Z-28 and banged away until it got hot. I kept it and the Vette under 2000 rpm's until they are at run temp. That is easy to do with 6-speeds. Yes I have talked to GM and the answer is piston slap. That is the company answer. My Z-28 had 84,000 miles on it when I finally sold it in 2004. It used very little oil. It was the fastest Z-28 at our 1/8 mile strip here in Louisville. I also got 30 mpg on the road. So I decided to let it rattle away. No harm just noise.

 

So where can we buy the Baldwin B31?

 

I also heard that the FRAM GOLD filter also helps the oil flow better and reduces or even eliminates the piston slapping noise.

 

JOIN THE CLASS ACTION LAWSUIT AGAINST GM!!

 

I have built quite a few engines and I can tell you from experience that forged pistons will produce slapping noise until they are heated and expand to mesh with the bore. This is a big discussion when dealing with forged pistons vs. hypereutectic. One of the downfalls of the forged pistons was slap, however they had more strength in supercharged and nitrous applications compared to hypereutectic pistons. Hypereutectic usually are made up of an aluminum piston alloy that contains dissolved and free silicon. For this reason they do not offer as much of the expansion and contraction properties that forged pistons do.

Obviously, the question is how loud. If it is excessively loud than something is more than likely wrong. The question is what is acceptable and what is not. If you call any engine builder and ask his advice on forged internals I guarantee he will relay the above information as well.

My engine is doing the same and I am taking it to the dealer to have them check, so I have the documentation in the event engine damage does occur. I want to see them try to pull a quick one over me. I am taking it in on Monday so I will let you all know what happens!

 

Here's where I buy mine:
http://www.adiesel.com/prodinfo.php?itemid=2930

You can also check if there is a dealer near you by plugging your zip code in at the Baldwin homepage.

 

I have found that the K&N oil filter eliminates or greatly reduces this malady and these filters seem to be readily available at most auto parts stores (in my area).

 

OK, I'm confused... how does a different oil filter eliminate piston slap? It's not like the pistons and cylinder walls are pressure lubricated. The most likely cause of the piston slap in the LS series engines are the very short piston skirts used to reduce frictional drag, this reduces support to the lower piston area, and increases the chance of piston rocking in the cylinder bore until everything expands uniformly. The slight barrel shape of the pistons probably exacerbates the rocking condition until the temps come up. However both design features reduce piston to bore friction, and any reduction in total internal friction increases output efficiency.

zo6vettepilot

 

 

I have to say I agree as well. I don't believe it matters what oil filter you are using we are talking about expanding and contracting of alloys.

 

from what I read .. the piston slap issue was corrected 02 on ...

 

that is exactly what the problem is ... an oil filter might help should sticky or a lot of carbon on the lifters or valves be the issue .... but not piston slap. I know GM tried a ceramic coating on the piston to help with the problem but when they realized the magnitude of the problem they stuck their head in the sand.

 

You are fortunate ... get to church on Sunday!!!