Update on dealer rebuilt LS1....bad news!

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Mar 16, 2003
Well a few weeks ago I had my 2002 LS1 rebuilt because of piston slap. With 450 easy break in miles the slap/knock is back and worse then before the rebuild!
A bunch of parts including all 8 pistons were replaced so why would this happen? It is to early to tell if the new rings stopped the oil consumption but it is slapping hard again! I have not yet told the dealer so what would you guys say I should do at this point? Thank you again for any input!
LSI junk engines are being rebuilt here by the truckload! Holden dealers had the same problems. Now farmed out to a local engine shop who 'select fit' each piston to it's bore for the correct piston to bore clearance. Time consuming but has to be done. Appears your dealer has a lot to learn?
I would request no Demand a new engine.

But first do a UOA just so you have an idea of what it looks like in there.
It looks like Chevy small blocks are an exception to the conventional wisdom that factory machining practices have gotten better over the years.

Originally posted by Chris B.:
Well a few weeks ago I had my 2002 LS1 rebuilt because of piston slap. With 450 easy break in miles the slap/knock is back and worse then before the rebuild! I have not yet told the dealer so what would you guys say I should do at this point? Thank you again for any input!

Looks like it's time to get a new engine.
Even though for hot rodding I'll pick chevy engines . the advertising from a few years tells all... CHEVROLET THE HEART BREAK OF AMERICA...imo. But I really like World Product Engines ,don't know if they will swap and smog though?

[ September 02, 2003, 10:30 AM: Message edited by: Steve S ]
This is starting to depress me!

I really should thank the good Lord that this is probibly the biggest problem in my life at this time.

I'll call the dealer in the next few day. I'd like to talk to a few knowledgeable folks first.
The pistons are not forged. It seems that the bores are to big and the pistons use short skirts or none at all.

Originally posted by Chris B.:
The pistons are not forged. It seems that the bores are to big and the pistons use short skirts or none at all.

If it's just a fitment problem they should be able to fix it by matching pistons provided they know what they're doing. Problem is, if the bores are too oversized or out of round there's not much that can be done short of boring and fitting oversized pistons with the correct clearance.

If they need to do this, I'm with G-Man. Dump the stock GM pistons and get something that's higher quality from the aftermarket even if you have to pay for part of it yourself. Let them pay for the labor and the cost of new GM pistons.

I did this with a couple of items on my Mustang while it was still on warranty but I had an advantage. The service manager at the local Ford store was a good friend...

[ September 02, 2003, 01:33 PM: Message edited by: jsharp ]
LS1s are definitely hit or miss. My 98 Formula was bought new, broken in HARD (did over 130mph with less than 50 miles on the odo, and made my first trip to the dragstrip when it was one week old!) and did not exhibit any piston slap or oil consumption during the 2.5 years I owned it. I made 250 quarter mile runs on the car too, so it definitely was not driven gently.
Chris, I'd put more miles on it unless it sounds like it's nearing destruction, and I'd get an oil analysis before I return to the shop. I'd like the sample to be on the third oil change in this engine if possible. There will be a lot of normal break-in particles to be flushed out of the engine...what we want to see on the analysis are any break-down particles.

What is the warranty period on this work?

Or, let the engine destroy itself within the warranty period and get a new engine.

So few engines are rebuilt these days that few mechanics really know how and get enough experience to know all the details and tricks for the best job. Most mechanics just diagnose problems (some sucessfully and some not) and bolt in complete part assemblies.

Ken, Terry told me to break in the rebuild with a good dino oil. I drained what ever the dealer put in because I could not get a solid answer as to what they put in and the tech was not there at the time I picked it up. I put in Halvoline 10w30 with in the 1st 70 miles on the rebuild. I will drop the oil at 500 miles, 1,500 and again at 3,000 miles using all Halvoline 10w30 per Terry. I plan on donig a UOA on the last 1,500 miles just befor I put in the Mobil 1 I was using. I will still do this unless I decide to bring it back to the dealer right away but not sure yet.
I bought a 60,000 mile warranty when the car was new. If I don't seek a new engine or another rebuild I will ask the dealer for a free 100,000 mile engine warranty from the time it was rebuilt.
The shop forman said hes engine tech/builder was one of the best around so if they have faith in his skills they should back it up.
Don't get upset with these questions but

Why are using changing oil so much? This is totally unnecessary. It did not help, did it?
You should have driven it with the dealers oil till it was time to change via the service manual or what they told you. If I was the tech I might get upset that you did this, he may have used EOS (GM Engine Oil Supplement FM) and now you drained it out within 70 miles.

I drove my car the first year with the factory oil and changed it with about 5,400 miles. That was last Sept 15, 2002 and I have gone since then on the sale oil to about 13,000 miles, the oil light came on yesterday. No piston slapping here. If all the frequent oil changes was good, then my engine should be in worst condition than yours. Uses no oil yet.

btw-It has been said and I saw the TSB that LS1 Camaro and Firebird engines were factory filled with Mobil 2 from Sept 2001 to the end of production, this was confirmed by Scott Settlemire of Chevrolet. So if your car was built after Sept. 2002 it came with synthetic Mobil 1 5W-30.

I have changed oil 2x in 13,000 miles and 2 yrs. How many oil changes have you done?

Again, don't get mad at me but I think you are listening to other peoples advice when you should be going by what the owners manual says.

[ September 02, 2003, 03:22 PM: Message edited by: Mike ]
I thought that it was best to keep fresh oil in the car durring break in. To help flush out break in particuls.
Welcome to my world! I have a 02 Z28 and it has slapped since 500 miles. It currently has 7900 miles and it is still slapping happy. The engine does not slap at all when I first start it in the morning, but 15-20 seconds after that, all h3ll breaks loose. It sounds as if the engine is out of oil. My recommendation is to go back to the dealer and try to get an extended warranty for free....after that, drive it like you stole it....or better yet, drive it like Patman. No wonder his UOAs are less than exceptional

BTW, mine slaps like a diesel and runs like a cheetah. Best so far is [email protected] mph with a lid and free ram air.
Chris........I would have the engine re built and I would supply my own aftermarket pistons that were designed to get the job done.

These new factory pistons with their ring packs high above the pin and almost NO skirt are crap and are designed for CAFE gas improvement and nothing else.

There is NOTHING worse for a car nut than a mechanical engine knock.

Now they say that if it quietens down when warm , no harm is being done, but what hapens when you wish to sell or the car has 100,000 miles on it ( which ever comes first.)

As they say in my home country " Time to put some stick about "
I have a 2002 Trans Am with the LS1 engine and there is nothing wrong with it. Runs great, car is 2 yrs old next month with about 13,000 miles and has never been back for any warranty work or
any problems at all.

Does it make noise all the time or only when cold?

I also change oil per the monitor system, just went off, 7,600 miles and 5 days short of 1 yr.

[ September 02, 2003, 12:11 PM: Message edited by: Mike ]
Hot and cold. But not all the time. Last night I stopped at a stop light and It was slapping hard(fully hot engine). When I got home I shut it off and restarted it and it was quiet again.
LS1's are like a box of chocolates you never know how bad yours is gonna knock and slap!
Chris B... I'm sorry to hear your rebuild did not fix anything. I would definately demand a new engine. I have heard of a few people swinging an LS6 instead of the LS1 so that might be a positive outlook.
Are you hard on the Camaro? Do you red line it often, smoke the tires a lot or do you drive like me? Normal, I have never so much as chirped the tires or red lined the car and some of the younger guys are always claiming its crime that I don't race the car of burn of the expensive ZR tires. I never bought it to abuse it, and some just think that is outrageous.

[ September 02, 2003, 12:33 PM: Message edited by: Mike ]
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