I am currently buying parts to totally build a new LS1 engine for my 02 Z28 with only 26,000 miles on it due to a very severe case of piston slap. GM rebuilt it under warranty but the only thing they changed was the piston. To pistons with a thicker TEFLON coating.

The new pistons didn't change anything and GM and the dealer ship said the problem was fixed and they couldn't hear anything. Which was a bunch of BS. So I am having to spend a few grand on fixing the problem my self. From research I have done i believe piston slap is caused from over sized cylinders causing the pistons to be lose in the cylinder and knocking against the cylinder walls.

So I am hoping someone here has rebuilt an LS1 engine with after market pistons and could tell me if they have had and piston slap problems with after market pistons after a rebuild. I was thinking of using MAHLE brand pistons and rods. What brand have you guys used and what brand would you recommend?

Also if anyone here has torn down an LS1 with piston slap could you please post what you found in the engine that could be causing the knocking?


Joel

 

how bout the lunati rotating assembly from thunder racing?

good parts, good company and you know they have good service.

 

Yeah i have looked at the Lunati rotating assembly but they cost alot atleast for me. I already got a new stock crank and the MAHLE pistons and rod set cost about 750 bucks with shipping. But I don't want to go so cheap as to sacrifice quality.

I still would like to know if anyone has had any problem after a rebuild with piston slap. I would hate to rebuild my engine and be in the same spot.


Joel

 

Look into a set of Diamond Pistons.. they're good quality and a lot of guys from LS1tech run them. I personally have seen them in a 366 and it doesn't have any issues with Piston Slap...Most aftermarket ones don't, even without coating. I would have the machine shop blueprint the block as to make sure all the cyl. are the same size. If not have them opened up to the same, get the crank freshened with a 10 under cut, and you could even have the rods freshened and get a new set of pistons and rings. Add new bearings, and you have yourself a cheaply rebuilt motor. Figure $500 in machine work and new cam bearing install. Don't forget new bolts as well. Then do all the labor yourself and you've spent less then $2250 in parts and you're ready to go.

Good luck, and make sure you have a TQ angle guage for doing all the bolts/fasteners. You'll need it. And a good set of Tq specs since it is all TQ to yeild.

Chris

 

Thanks for the info crash4cyl.

As for parts I dont plan on using any old engine parts. I don't want to take a chance any of the parts could have been damaged from the knocking.

So I have already got a new LS6 block and a new stock crank. I haven't yet got the chance to get the block checked out to see if all the cylinders are the same size. And what is blueprint the block?

As for building the engine myself I have yet to ever build an engine but I have been reading alot on building an LS1. Im not sure yet if I want to learn how to build my first engine on my LS1 since I will end up spending a few grand on it. I couldn't afford a big learning mistake. So if anyone knows any place in Oklahoma who can build LS1 and maybe install it also let me know.

I also plan on getting a nice set ot stage 2 ls1 or ls6 heads but i haven't decided on the cam yet tho. I want my car to be an everyday driver so I don't want to put a huge cam in it. And I don't want a real radical idle either. I have been considering a stock LS6 cam maybe.

So if anyone else has any good engine build info or ideas that could help me in anyway please drop me a post. Thanks for the replies so far.

Joel

 

One question?? How does your car run??? I mean other that noisy??

 

I'd get a set of Diamond Pistons, and a set of 6.125" Eagle H-Beams and call it a day. I have made over 700fwhp with those items and never had an issue once.

 

Other than noise my car has started to burns about 3/4 a quart of oil ever 1000 miles. Seems like alot to me. My gas mileage is crap. Im lucky if I get past 200 miles a tank city driving.

I took my car to a local shop and told them my problem. The guy that checked it out worked a local machine shop for years and said he didn't think the knocking was normal at all. He hooked up (I think he called it) a diagnostic lab scope up to the knock sensors and he said that they were reading so much knocking that is was retarding my timing and causing my bad gas mileage.

I even took it by a couple more local shops and told them my problem and how my car was still under warranty at the time and they also said they couldn't believe the dealer and GM called the knocking normal.

I took this info to the dealer and GM and i got the same answer. There was no problem with my car. This was all about 10 months ago. And its just in the past 3 or 4 months that my car has started burning more oil as the knocking gets louder. 10 months ago it only burned about 1/8 quart ever 1000 miles.

So I believe there are some serious problems with my engine. Problems GM should have fixed.

 

I agree. But why fix it yourself. Get a lawyer and push the dealership to stand up. My truck and my 'bird knock a little only when cold and they both run great. So I guess that I'll knock on wood for continued good luck.