Spellbound

I am having my pistons replaced do to excessive piston slap by my local dealer. They sent the pistons out to have the rods/pins pressed in and when they came back they did not put them in the order the dealer sent them out in, so they could not reuse the rings. Now they want to put new rings in but they don’t want to resurface/hone the cylinder bores. They said with the molly rings you don’t need to hone and the most important thing is that the cylinders are straight. The dealer said that the engine still had a good cross hatch finish on it and I shouldn’t worry. What do you guys think?

grinder11

iTrader: (1)

O.K., you asked and here it is: I think it's sounds like horseshit!! Even IF- a BIIIGGG IFFF, it is right, it's still wrong! I have heard a lot of this on the forum, and I think we should empower ourselves with anything we can, and let's start with naming dealers names. Like so and so Chevrolet, or Such and Such Pontiac, etc., doesn't give a damn about customer service!! I love my car (A '00 C5), but G.M. and their dealers, with this attitude, SUCK!!!! Here we lay down a hard earned $25,000.00 to $50,000.00, or MORE for their product, and the ONLY reason it's apart is because of **** assembly, machining, design, or all of the above, NOT US!!! First time I drove my car when it was under 55 degrees, I honestly (Don't laugh, I'm serious!) thought someone had borrowed my spare key and taken it for a drive while I was at work and missed a gear or something, then carefully parked it exactly where I had left it, as the rods sounded like they were gonna show any minute! I actually stopped my car, and quickly shut the motor off, and felt the temp of the heads to see if it had been run that day, as it would have been somewhat warm, but not enough to show on the gauge yet. Later found it was a piston slap (When the oil pressure read 55-60 lbs. for a minute and it was still there, had to be.). G.M. should take a flyin you know what at the man in the moon, & hope he aint got aids. This is a no brainer. After all the work to tear a motor down (And out, no small feat, I might add!), and take off 24 individual rings, or more, put on a different set of pistons, and they can't plug in a drill motor with a 600 hone or cylinder de-glazing stone chucked up for 15 to 20 minutes to do it right the rest of the way? If it woulda been right to start with, they wouldn't have to do it half assed twice, right? It makes me sick.

Gold Z

iTrader: (3)

Make sure they check the cylinders for correct bore diameter and out of round. My factory block was replaced by GM for three cylinders being out of spec.....It had been torn down to replace the pistons but after the block was checked they replaced the entire longblock.

LOnSLO

iTrader: (15)

I may be wrong on this, but I thought the replacement rings had a friction coating on them to deglaze the cylinder wall. After a few minutes, the coating wears off, and the new rings can seat.

HumpinSS

iTrader: (1)

GO above the dealer and cal either customer service or the district rep and talk with them directly

grinder11

iTrader: (1)

I agree. Play Dirty Harry, and tell 'em "Ask yourself a question. If it was your engine you removed, tore down, re assembled, and re-installed, would you spend another half hour honing the cylinders? Well would ya punk"! I didn't mention the cylinder walls being in or out of spec because I assumed (Never do this!) that this was already done and all that was wrong was piston specs. More ammo for my previous post on the machining/design portion. I have, and recommend to all, the new LS1/LS6 how to book by Will Handzel. Excellent reading. In it, or maybe it was the recent issue of Hot Rod,he says G.M. is spending over $400,000,000.00 on warranty work as of press time!!! This is analogous to us being stuck with a defective crankshaft and G.M. would remove and replace it with a new crank, but use the old bearings!! If worse comes to worst, you would think we all should have this option: offer (grudgingly) to pay 'em a half hours labor rate to just do it. Hard to imagine G.M. with this attitude these days, with all the rice, and other, competition out there. This is like Bill Gates worrying that the price of plastic will drive up the price of a 19" monitor by 17 cents.

technical

It's not like the engine was put together that well from the factory to begin with. If you want the perfect engine rebuild, don't take it to the dealer for warranty work. And finally, don't worry about it. The new rings will either seat or they won't. If they don't then the dealer gets to re-do the work. I'll put money on they'll seat just fine.

Remember that GM pays the dealer for the warranty work. The dealer will not do anything for free. So unless either you or the dealer convinces GM to pay for a honing, you aint' getting one. And I wouldn't trust a dealer tech, who rarely does machine work, to hone your engine. That's the reason they sent the pistons and rods out in the first place.

Gary Z

This may be true but most of our engines were put together extremely well at the factory. Factory tolerances today are significantly tighter and assembly much more precise than in decades past. The reputation of the Gen III engine rests upon quality as much as performance. The best custom builders undoubtedly do a better job than any mass producer but many professional mechanics do not and can not.

technical

Really? What has changed in the past 10 years?

Gary Z

Straight up, I’ll admit that I am not intimately familiar with engine production history. My pronouncements are conjecture. I have owned several SBC engines and currently own one LS1. The superiority of the LS1 is incontestable by any measure unless you value simplicity and oil leaks. It may be that the tolerances and torque specifications of the LT1 are not significantly different than the LS1. I assumed that LS1 specs are tighter. I consider myself a good mechanic. I know that it is often difficult to measure within modern tolerances much less meet them.

technical

The improvement with respect to engineering has definitely made leaps and bounds. Specs are particular to a specific engine. Comparing the LT1 and LS1 specs isn't worthwile.

I would say that new rings in an engine with less than 36k (warranty?) without honing will be just fine. You could ask how I know this, but probably already know that answer.

Gary Z

I think we agree. I hope I didn’t seem contentious. I just didn’t want to leave what I perceived to be mild GM bashing, unanswered.

BBQLS1

I think you can compare the accuracy and precision of clearances being within spec.

technical

The accuracy and precision achieved by the factory has not changed in many years. Specs change from engine design to engine design absolutely, but the factory has never been known to build a "tight" motor.

Spellbound

The car has 16k miles on it. 2002 WS.6 CE vert. Thanx for all the replies!

BBQLS1

Manufacturing equipment and process has improved a great amount due to automation, digital interface, improved measuring techniques(through electronics instead of mechanical measurement) and robotics. This will improve greatly the precision and accuracy. Try making something on a old style mill or lathe, and try making the same piece on a modern design mill or lathe with a digital readout. The modern stuff ROCKS. Besides, you don't want all clearances tight. You want the rings to seal good (all depends on boost or nitrous), but loose bearing clearances often make more power hence when an engine breaks in it makes more power. Main bearings for an everyday driver you want maybe around .002" and you will see racing applications (especially drag racing where you have short races) you may want closer to .003"

MCBRIZ28

iTrader: (2)

I myself would rather have them check the roundness of the cylinders and not hone with a hand drill and cylinder hone they can do more damage with that thing than ever image it will remove more than just the glaze it will open up the clearances which is the problem in the first place better them not hone than have a crazied tech. make the cylinders look like a oversized egg in shape. The best way would be hone it out on the correct cylinder hone not hand held type to .005 oversize and install correct oversize piston and rings. just my 2 cents.

BBQLS1

Yeah, if a tech can't do the job they shouldn't. I am kind of supprised, they don't just replace the engine (I am thinking this is warranty work).

technical

Automation has improved precision ie. the process of repeating a task over and over with the same "exact" results. Doesn't guarantee accuracy. People are still involved. Automation has sped up production yes, but engines built from the factory are just mass produced parts. They are not race engines that were put together with stricter tolerances and blue printed.

Tolerance are just that...windows. If a main is good between .005 and .006 then .005, .0055, .006 all work. If you want that .2hp from your engine go for it. Don't forget to index your plugs as well.

BBQLS1

Mains are usually between .0015 and .003. and it does make a difference. That's why you see so many people on this site saying a "broken in" car runs quicker than an "off the lot" car. Bearing tolerances get looser and rings seat better.