View Full Version : LS1 piston slap issues.

09-03-2009, 06:41 PM
I need a no bullshit answer for replacing the LS1 engine with an LS6 engine in my 2000 Z28 A4 under my extended warranty because the piston slap is getting progressively worse. My car has only 79000 miles and I only use Royal Purple products in my car. I can get the replacement LS6 for about 300.00 more then the replacement LS1. They both come complete with intake,plugs,wires,coil packs,TB, oil pan,and water pump. Will there be a problem with the EGR on the LS1 harness and can I just plug in my harness into the LS6 and cut the intake open for the EGR? Should I get another computer and have the EGR, after cat O2 sensors deleted and just plug up the EGR openings on my headers? I know I will have to swap over the TB due to the ECT on the Corvette LS6 motor, but what other problems am I not seeing? Any and all info would be greatly appreciated. Thank you.

09-03-2009, 06:48 PM
your beat bet would b findina a egr from a 01-02 then its plug and play....or just delete the egr, add a ls6 intake get a tune, tune out rear o2's and pick up evin more hp then just the ls6 offers.....then mod the shit out of it

09-03-2009, 06:50 PM
....oh yea define your pistion slap???

09-03-2009, 07:58 PM
try something other than royal purple. never know, that might do it.

09-03-2009, 08:03 PM
my car piston slaps like a MOFO. but its fine.. put a cam in it, and its harder to tell when its slapping when its too busy loping like crazy.

09-03-2009, 08:58 PM
Piston slap is when you first start up a ls series engine on cooler mornings and you hear a knocking or slapping noise until the engine warms up. This is due to the factory using a piston that is slightly too small for the engine cylinders and it allows the piston skirt to slap up against the cylinder bore causing excessive wear in the cylinder bores. Once the engine reaches operating temp it gradually goes the away because the aluminum piston has expanded enough to allow the rings to align the piston correctly in the cylinder. It is a common problem and in some cases the engine will last a couple hundred thousand miles with no issues or it will gradually get worse and cause the piston rings to fail prematurely.

09-03-2009, 09:10 PM
Here is a web sight that has some info about some of the worst case Piston slap problems.

09-03-2009, 11:15 PM
Here is a web sight that has some info about some of the worst case Piston slap problems.

I have had that site bookmarked since I bought my piston slappin 99 Z-71 in 2002. It now has 195K on it and drives like when I bought it. No oil consumption issues etc... Most of the noise is caused by carbon builup on the short piston skirt which does knock for a few seconds when cold. Seafoam it and it will prolly go away for a few K and come back in a few K when the carbon bulds back up. I try to run only top tier fuel and it will greatly reduce the buildup hence lesson PS. Just search google "top tier fuels" and you will see what kind to get. Around here only Shell and Chevron make the grade....BTW IIRC GM BMW Toyota and others recommend only running TT fuel in thier cars. This is a little known fact.

Having said all that if you can get a LS6 from warranty HELL YEAH:burn: