[gtofan]

I think the new GTO is the best thing Pontiac's done in 40 years. Being an old guy, I was around as a (very) young teenager when the '64 was introduced, and I'm as excited about the new one as I was about the original (even though I couldn't afford one back then). Based on everything I've read about the GTO in the various magazine road tests and in this forum, I'm going to get one (when they finally do start to be delivered). Because of everything I've seen on the web about a particular problem with GM engines, though, I was wondering if some of you LS-1 experts could set me straight on the so-called piston slap/high oil consumption problems that the LS-1 seems to have experienced in the last few years. There's a lot on the web about it - they even have a site devoted to it: www.pistonslap.com.

As I understand it, GM made a running change to the LS-1 in 2002 that decreased cylinder-to-bore clearance, changed the oil scraper ring, and added new pistons with coated skirts to prevent scoring due to the reduced clearance. Is this another one of those "urban legends"? If it's not, did GM's fixes really cure the problem? Should I worry about buying a new LS-1 (particularly in a $33,000 package) that will develop these kinds of problems in the future? Any further insight or additional info would be much appreciated.

 

[HD926]

GTO

Hey gtofan I work for GM and those changes have been made that you mentioned. I have owned a 2002 Z-28 and a 2002 ZO6 which 1 has the LS1 and other has the LS6 and had no problems with either. Now there is a argument on break-in between poeple and I am 57 years old and had dozens and I do mean dozens of high performence cars and still do. All cars that I have had I break in the way we were taught (Vary the speeds up and down no steedy speeds for a long period of time---- no full throtle for awhile so on and so on. All of the probaly 30 to 40 cars I have owned I have never had any problems. Growing up friends of mine that said break them in like you are going to run them always did --- Valve problems -- burned oil --- blown motors. Break it in easy and you won't have any problems. By the way how old are you Iam 57. HD926 from KC MO.

 

[CMNTMXR57]

This is a touchy issue. A lot of the problem with piston slap is more seen on the truck side with their irion block version of the LS1 moreso than the LS1/LS6 itself. The oil consumption issue is also a hit or miss thing. When you consider all the LS1 and LS1 Vortec engines out there on the road, you'll find that the actual number of them with these problems is quite small. We only had a handful come back that needed any serious work.

It has to do with the lightweight hyperteutic (I probably murdered that spelling) pistons they use today to decrease rotating mass. Naturally between the material used and the lightweightness of them, they don't absorb the slapping sound as well as such you hear it. An old 350 with a cast iron block and old fashioned cast pistons had piston slap too. All engines do to some degree when they are started cold. The difference is, that old engine "insulated" the sound so you didn't hear it as readily. GM to quell some of the complaints also put a special coating on the pistons to help reduce the noise some.

If the noise goes away within the first few minutes of operation, that is considered normal and nothing is wrong. If after the engine reaches full operating temperature and the thing still sounds like a diesel, THEN there is a problem. You want to hear piston slap, you should hear my 8.1L in the morning. It sounds like a Cummins turbo diesel!! But after about a minute after it warms some, oil has gotten back up to coat the cylinder walls to help "cushion" the piston some, it runs like a top. Enough to pull 15,000 lb trailers regularly without a whimper and enough to propel it to a 15.84 in the quarter mile. Not to bad for a truck that only weighs 7,000lbs, had 60psi in the BFG All Terrains, and had only intake and exhaust mods.

Oil consumption to me personally has to do with people who pull out of the dealer lot with a brand new car (7 or 8 miles on the odo) and leave in a cloud of tire smoke. They come back at 5,000 miles wanting to know why their engine burns a quart of oil every tank of gas? Well, maybe if you had let the rings set by properly breaking it in, instead of hammering it to redline on the way out after signing your papers, it wouldn't be burning oil!!

Point is, don't worry about these problems and let them sway you from purchasing this car. For every one person that has a problem with these engines, I can come up with 50 that love them and have not had a problem. Every car made has it nuance problems, the LS1 engines are just the same.

 

[gtofan]

HD926 that's good news - like you, I was taught to break in engines using varying speeds, throw in a little mild acceleration in the upper gears (3rd or 4th) once in awhile (not wide-open throttle or high rpm) to load the engine and seat the rings, no extended cruising at one speed, and generally give all the machined surfaces time to adapt to each other. I know that modern engines are machined to closer tolerances, and that many believe the "old fashioned" break-in practices no longer apply, but I've done this on every new car I've owned with very good results. Also like you, I've seen guys break them in (or just break them, period) using the "drive it like you hate it" method - with predictable results. Thanks very much for the quick response - I'm 54.

 

[gtofan]

CMNTMXR57 - appreciate the informative response. Thanks to you and HD926, I'll now just worry about what color I want it in....

 

[CMNTMXR57]

I hear Impulse Blue is an awesome color. Oh wait I'm a tad bit biased! You'll also have to pick trans choice which you'll opt for a 6 speed, RIGHT? LOL! Just kidding.

I'm with you 110% on the break in. I've done that for every new vehicle I've owned. Got 396,000 miles out of one, 220,000 out of another, and several 100k miled cars too! If you take care of it, it'll take care of you.

 

[gtofan]

Funny you should mention that - actually, Impulse Blue is looking good to me - would like to see one in the Bardados Blue variety too, though. 6 speed manual is a foregone conclusion (at least for me) - hope you get you get your car soonest. Thanks again.

 

[sukkoi19]

Truthfully, its just one of those annoying things you have to put up with from the LS1. My Z/28 makes noise when it fist starts, but once it is fully warmed up its fine. Personaly I think the performance trade-off is well worth it.

 

[Superwildcat]

Most of the ZZ4 engines I have heard have some noise even when warmed up.

 

[cvp33]

My 2002 Tahoe has the "slap" on start up as well. Almost sounds like dieseling though not as pronounced. As far as Impulse Blue goes, you mean they are making other colors too?

 

[CMNTMXR57]

The Vortec 5300 in your Tahoe is nothing more than a cast iron version of the LS1 albeit a tad smaller.

 

[mistermike]

It's not just this side of the Pacific. Gleaned from an Oz site:
HOLDEN=Heaps Of Loud Damaging Engine Noise

 

[mmciau]

MisterMike,
HOLDEN = Helps Old Ladies Drive Engineers Nuts

Mike