I broke it in nice and easy. Keept it under 55mph for the 1st 500 miles like the owners book said. No full thrott starts or red line. I changed the oil at 500 miles, 1,500 miles and again at 3,000 miles when the car was new. I'm doing the same to the rebuild but it is slapping hard again with 450 easy miles on the rebuild. Acctually it is my wifes car and she is very easy on it. After it was borken in the 1st time (3,500 miles) I got to drive it once a week or so and I did go fast once in a while. I did redline it and spin the tires to fish tail but not often, coupel times a month at most.
Update on dealer rebuilt LS1....bad news!
- Thread starter Chris B.
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Chris B. or maybe Patman - Do the LS1 engines use forged pistons? If so they'll need to be fitted more loosely than your typical cast piston. This would cause some noise until everything is up to operating temperature. Pistons with shorter than normal skirts would also cause this kind of noise.
The real test is how long they last. Do they wear out prematurely or is it just a perception problem.
Just curious...
[ September 02, 2003, 12:54 PM: Message edited by: jsharp ]
The real test is how long they last. Do they wear out prematurely or is it just a perception problem.
Just curious...
[ September 02, 2003, 12:54 PM: Message edited by: jsharp ]
There is no way I'd accept this if I were you. If they won't give you a new LS6 shortblock, then demand that the engine be torn down and all the cylinders mic'd and checked to make sure none are out of round. Then tell 'em since the GM pistons obviously can't solve the problem, you want eight AFTERMARKET pistons used. The folks over at LS1.com can probably tell you which ones are the best, but that should put an end to your slap problems (provided you don't have any bad cylinder liners).
Now in my professional opinion this is the only way to break in a motor, redline it on your way out the garage. Actually break it in the way you plan on driving it. I have never had a problem.
CRW
I'm not real sure what I will do yet. I think I will see what happends after the 3,500 mile break in and see if it is still burning oil. If so I'll take it to the dealer for a new engine and cross my fingers I get a good one. If no oil cunsumption then I will just ask for a 100,000 mile engine warranty from the rebuild mile marker. They should have no problem giving me this if they have any faith in their rebuild work.
I took a good hard look at GM piston slap before I bought my 03 Chevy 1500HD 6.0 about a month ago.
www.pistonslap.com is enought to scare a guy silly! From the research that I did, It looks like GM finally did some slight redesign of the engines (at least for the 6.0) to help with the piston slap issue. The used a different pistons, and some parts were coated with something. I am just crossing my fingers, I really love this truck.
www.pistonslap.com is enought to scare a guy silly! From the research that I did, It looks like GM finally did some slight redesign of the engines (at least for the 6.0) to help with the piston slap issue. The used a different pistons, and some parts were coated with something. I am just crossing my fingers, I really love this truck.
As soon as I looked at the pistons in the pictures I knew what caused the slap.
Look at piston #8.
Notice the streaks that start at the top of the piston and go down to the top ring?
Now look at the other pistons down the bores.
Notice the chips out of the pistons' crown around the top above the top ring.
That is classical detonation damage.
Look at piston #8.
Notice the streaks that start at the top of the piston and go down to the top ring?
Now look at the other pistons down the bores.
Notice the chips out of the pistons' crown around the top above the top ring.
That is classical detonation damage.
Almost looks like carbon deposits on the top of piston 8?
If the noise goes away after the motor warms to operation temp, I could live with that. I just use the best oil money can buy and not worry about engines. That just me, I don't think a vehicle is worth wasting my time worrying about.
A friend has a 1999 Silverado that has made this noise the web site is gripping about since it was new, he still has the truck. I talked with him a few months back, he has over 100,000 miles and his engine had not failed yet. He has been on hunting trips to Montana (from Michigan) and been all over. He was sure his truck was going to blow up 4 yrs ago and nothing has happened. But he just does not worry about it and enjoys his retirement. btw-When this started the dealer gave him free oil changes with Mobil 1 for the life of the 3 yr warranty and he says he continues to use it.
[ September 03, 2003, 08:05 AM: Message edited by: Mike ]
If the noise goes away after the motor warms to operation temp, I could live with that. I just use the best oil money can buy and not worry about engines. That just me, I don't think a vehicle is worth wasting my time worrying about.
A friend has a 1999 Silverado that has made this noise the web site is gripping about since it was new, he still has the truck. I talked with him a few months back, he has over 100,000 miles and his engine had not failed yet. He has been on hunting trips to Montana (from Michigan) and been all over. He was sure his truck was going to blow up 4 yrs ago and nothing has happened. But he just does not worry about it and enjoys his retirement. btw-When this started the dealer gave him free oil changes with Mobil 1 for the life of the 3 yr warranty and he says he continues to use it.
[ September 03, 2003, 08:05 AM: Message edited by: Mike ]
I would suggest that you return the car to the dealer immediately. You want this problem documented, and you do not want to give GM the opportunity to argue that you contributed to the motors damage because you chose to drive it knowing that it was defective.
Concerning using aftermarket pistons, it may solve the problem, but will void your warrantee.
It sounds like your dealer is trying to help you out. I would suggest that you keep after them to rectify the problem and if they cannot start discussing a buyback of the car.
Cary
Concerning using aftermarket pistons, it may solve the problem, but will void your warrantee.
It sounds like your dealer is trying to help you out. I would suggest that you keep after them to rectify the problem and if they cannot start discussing a buyback of the car.
Cary
My advice:
Get an LT1!
(Sorry I just had to say that, LS1 guys are always telling us to get one).
Get an LT1!
(Sorry I just had to say that, LS1 guys are always telling us to get one).
quote:
Originally posted by Kuma:
My advice:
Get an LT1!
(Sorry I just had to say that, LS1 guys are always telling us to get one).
Actually, the LT1 are much much quieter, regarless of what GM Engineers say, but I still prefer the LS1.
Rick
Thanks to all for the help! I got through the 1st 500 mile break in. Had it out on I25 today and she seems to have all the power it had before. I will let you know what the dealer says as soon as I can take her there. I'g going to ask for the tech who rebuilt it listen to it. Is slaps all the time even when hot but sometimes worse then others. It never makes much noise on the 1st start up but then starts with in 30 seconds. It slaps hardest on hot starts. If you crawl under the engine it is quiet loud. It sounds like a Knock,knock, knock, knock, knock at a rate of about 20-25 knocks every 5 seconds at ldle.
Hi Chris,
I was one of few people who recommended you to ask for rebuild. Now I feel like it's partially my fault that problem was not solved.
I think that you should definitely ask them to put in a new engine (LS6 hopefully). If they say "no", but would agree to another rebuild I think that people who recommend aftermarket pistons are right.
I don't know how much these pistons cost. It might be reasonable in this case to get aftermarket rings, connecting rods, and maybe even valves and springs. It would be nice if dealer will cover at least GM portion of the cost of new parts.
My personal opinion is to insist on every possible warranty work. That way maybe manufacturer will understand that making a good, reliable car is cheaper compared to warranty repairs afterwards.
If we say "Oh, OK, that's fine. I can live with slight piston slap." Car makers (mostly American brands) will continue to sell us half a "lemon" half a piece of bad designed sh*t. If they want to make it right – make it the right the first time. Thus it is cheaper and more efficient for everyone.
Regards,
I was one of few people who recommended you to ask for rebuild. Now I feel like it's partially my fault that problem was not solved.
I think that you should definitely ask them to put in a new engine (LS6 hopefully). If they say "no", but would agree to another rebuild I think that people who recommend aftermarket pistons are right.
I don't know how much these pistons cost. It might be reasonable in this case to get aftermarket rings, connecting rods, and maybe even valves and springs. It would be nice if dealer will cover at least GM portion of the cost of new parts.
My personal opinion is to insist on every possible warranty work. That way maybe manufacturer will understand that making a good, reliable car is cheaper compared to warranty repairs afterwards.
If we say "Oh, OK, that's fine. I can live with slight piston slap." Car makers (mostly American brands) will continue to sell us half a "lemon" half a piece of bad designed sh*t. If they want to make it right – make it the right the first time. Thus it is cheaper and more efficient for everyone.
Regards,
Patman
Staff member
The LT1s exhaust note is definitely louder than the LS1, but are you referring to piston slap instead? Some LT1s do have minor piston slap, mine shows up at about 1800-2000 rpm but only when the engine is cold and it's very minor, hardly noticeable.quote:
Originally posted by Last_Z:
quote:
Originally posted by Kuma:
My advice:
Get an LT1!
(Sorry I just had to say that, LS1 guys are always telling us to get one).
Actually, the LT1 are much much quieter, regarless of what GM Engineers say, but I still prefer the LS1.
Rick
The LS1 is definitely a smoother running engine, but I do love the sound of my LT1 better than my old LS1. I've got the SLP 2OTL exhaust on my LT1, which sounds much better than the open cutout I had on my LS1. I do miss the extra horsepower my LS1 had, a lot!
just outta curiosity - who says its piston slap?
I talked with a long time Friend who is a P-B-GMC dealer (got my TA from them).
I told him of your problem, curious if he had any knowledge about this and if I was going to experience this at some point. He was aware and according to him these engines have a noise issue. Its noise related to piston design and called piston slap which GM clains is not harmfull(?). It may be GM BS and others may disagree about the whole issue. Accordingly all the engines in this family are prone to this condition. Now this is info someone at GM tech told him and he related it to me. Who knows, I though I would share what he found out.
I was discussing the benefits (dealing him down in cost) getting an extended warranty when he told me to wait. He had some inside knowledge that letters were coming in the near future extending the warranty on the engine to 100,000 miles for car and truck owners. We have to see if that happens for F-body owners also, he seems to think its in the works for both cars and trucks.
btw
I would recommend using a top shelf 10W-30 synthetic oil, and follow the owners manual for service intervals.
[ September 04, 2003, 04:32 PM: Message edited by: Mike ]
I told him of your problem, curious if he had any knowledge about this and if I was going to experience this at some point. He was aware and according to him these engines have a noise issue. Its noise related to piston design and called piston slap which GM clains is not harmfull(?). It may be GM BS and others may disagree about the whole issue. Accordingly all the engines in this family are prone to this condition. Now this is info someone at GM tech told him and he related it to me. Who knows, I though I would share what he found out.
I was discussing the benefits (dealing him down in cost) getting an extended warranty when he told me to wait. He had some inside knowledge that letters were coming in the near future extending the warranty on the engine to 100,000 miles for car and truck owners. We have to see if that happens for F-body owners also, he seems to think its in the works for both cars and trucks.
btw
I would recommend using a top shelf 10W-30 synthetic oil, and follow the owners manual for service intervals.
[ September 04, 2003, 04:32 PM: Message edited by: Mike ]
Thanks Mike! That is nice to know! I'm glad you have a good engine and no problems! I really could live with the noise but not the oil burning as long as they back it up wit a 100,000 mile warranty.
My 2003 Silverado with the 5.3 V8 also has start up piston slap but it goes away after 15 seconds with out fail and when it does slap it is a fraction as loud as the LS1. I still love this car and it is a blast to drive in! The LS1 will smoke most other cars out there. I just love it when a "ricer" pull up to me at a light. Haven't lost a race yet! I just hope she has a long life ahead of her(200,000-300,000 miles)
My 2003 Silverado with the 5.3 V8 also has start up piston slap but it goes away after 15 seconds with out fail and when it does slap it is a fraction as loud as the LS1. I still love this car and it is a blast to drive in! The LS1 will smoke most other cars out there. I just love it when a "ricer" pull up to me at a light. Haven't lost a race yet! I just hope she has a long life ahead of her(200,000-300,000 miles)
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