I don't have much else to add to this except, I know 04blacksilverado personally and he's a stand up guy. 12secss knows his **** I have seen numerous posts of his and George knows what he is doing.

Just for ***** and giggles I measured some stock pistons I have and none of them match.

Does your machinist know that piston noise is a factory installed option on these motors?

And I want to get in one more time before this gets locked IB4TL

 

Yes he has a little experience buuilding these things.

I just think it's funny how people on here can judge someone they have never met and parts that they have never even seen a picture of.

04blacksilverado isn't that much of a stand up guy or he'd be true to his word, and just take them back and sell them to someone else.

 

Dude they are USED get that through your head. Steve is a stand up guy, just like 99.9% of the other people on this board. You are the one causing a problem. You are pissed that your machine guy wants **** perfect, when they never are. Especially when dealing with stock parts. And please, enlighten us on some of the thousands of cars this guy has build. Someone of that caliber must be well known in the racing world.......

I would be pissed if I spent money on parts and then the guy I was paying didnt want to use them becuase they might not work up to his standards. That is why I let my guy tell me what parts will work the best and that is what I go with. That is their job so I trust them. But with the pistons only being off that much and knowing that is a NORMAL thing for stock pistons, it is obserd that you would expect to get refunded for a part that lives up to its expectations.

And talk about a "stand up guy", you want Steve to take them back and then sell them to someone else That is a very stand up like idea
















IB4TL

 

I have seen the pistons I hung the rod on the new piston....

 

I must have missed something.

(Not trying to be an *** but...)
I don't think anyone would use stock GM pistons on a performance build. I wouldn't use them if they were new from the factory and free. If you're building an engine for an un-boosted daily driver etc, then they should be fine as they are in GM tolerances.

So, why the used stock pistons over a new or even used set of forged pistons?
If your build is spec'd out so tight that a .007 variance skirt is an issue, your builder should have told you "Not just no but, hell no" to used stock pistons.

If you feel you can't use them, sell them with the variance clearly stated and you won't have a guilty conscience.

I'm understand that a straight refund would be the best result for 2002coupe but I don't think the product was misrepresented to warrant that.
And if you don't mind...what did those used pistons cost you?

 

Dude,

I do not need to answer your questions, but I will. I have built and helped build a good amount of engines, mainly SBCs. And as for machinign experience, that is part of my job. I interact with machinist everyday and we work to gether on what tolerances the machines are capable of holding, without getting very expensive. And with tighter tolerances, the price begins to skyrocket. Hence why ANSI, ASME, SAE, ISO ... etc. have standards and specific tolerances for machining practices, which I am certified for. Sounds like you have no experience even near an egine (besides sitting in the driver's seat ) if you are questioning our experience. And what is this internet experrience, I am going off of what I have measured when assembling engines, and piston skirt deviations are not much of a concern in stock rebuilds. Now if it is a performance/racing engine, then yes ... but I would be a fool to even consider using used stock pistons for such an application. From your posting, I know you have no idea what it takes to build an engine, nor have you posted any facts to support your claim or common sense to reject these pistons for your build (what are you building?). Good luck finding stock factory pistons directly from GM with less variance then .010". Hell even the Aerospace connectors I currently design (which need to meet extremely strict tolerance requirements) can be with in .010" specs in most areas. And these are used for such military aircrafts as the B2, F22 and other future projects.

If you (and your machinist) are so **** about specs, then call up JE, Mahle (they make the OE pistons) or Diamond and spec out pistons that are stock replacements with zero deviance in the skirt dimension. You will find they will not be cheap, and they will question why the tight tolerance on the skirt dimension. That distance alone does not determine if a piston will rock in the bore, the diameter of the piston vs the bore (which can be as much as .003" difference) along with a long skirt will determine that. Now if he had said they were .030" - .090" then it may be cause for concern (possibly not).

As for the refund deal, that is between you and him. Just admit to him that you no longer want them, don't feed him any BS. Be honest and much more informed. Also, check out the service manuals for LS1 to find out the true specs for those dimension, you will see your machinist is way off. I can post these values later tonight if so desired.

 

This is not an all out performance build. I will not have a turbo, aftermarket heads, supercharger, nitrous, etc... All this was intended to be was a LQ9 with a mild cam. Nothing too fancy.

I never claimed to be a machinist, or know all of the tolerances of GM's specs.

All I have to go by is the word of someone who i know personally, that has much more experience than a lot of people.

The seller said if i was unhappy with the deal he would refund my money. Im not happy and he's not refunding.

Everyone views situations differently, this is my situation and how i think it should be handled. It shouldn't be a big deal to refund my $. Everyone would be happier, and there would be no hard feelings if he did it.

 

Does anyone know where i could find GMs actual tolerances they go by for their pistons?

 

What does IB4TL mean? How much did you pay for the pistons?

 

These pistons are probably no different then the millions of other stock pistons GM has installed. Just because your machinist doesn't like the variance of these stock pieces does not mean you were sold a bad set.

The way I see it 04BlackSilverado can take the pistons back if he wants to but, certainly doesn't have to.

BADMOFO - IB4TL means In Before The LOCK!!