**I'll preface this and say that I have contacted the engine builder to ask for an explanation and what needs to be done to make it right. I'm not here to sling mud, but rather get more professional opinions from people who see these things more frequent than I do**

I am going to post this here in hopes to get a better idea of what I am working with and what should be done. I don't know a whole lot about engine block machining, but I can spot when something doesn't look "right".

I just got my engine back from a well-known shop. Upon inspection, I noticed some asymmetries with some of the sleeves. This is an LS2 block that was perviously untouched. It was bored to 4.020" to clean up some surface rust. This first picture shows cylinder 4 on the right side and cylinder 6 on the left. Notice how thick the left side of cyl 4 and how thin the right side of 6 is? None of the other cylinders are nearly this bad and the entire drivers side looks really good upon visual inspection.



This is where it gets a little worse in my eyes. This picture shows cylinder 6 on the right and cylinder 8 on the left.



I have heard from reputable people that this is absolutely not right and that they haven't seen any core shift like this in any LS2 block. I have also been told to cross my fingers and run it. However, I am not really the kind of person to "cross my fingers" and hope for the best. I want it done right.

Thoughts?

 

Doesn't look right at all. Post a picture of the entire sleeve on both cylinders. It's got to be extra wide on the other side then? It's like it has .020" off the one side and the other is almost at the factory position.

 

Correct, they are wider on their left (rear) side.

I'll try to get a entire shot asap.

 

So this block was re-sleeved or these are the stock LS2 sleeves bored out .020"? If those are the stock sleeves then I don't see what they could have done about the sleeves not being the same OD. That is what we're talking about here right? #6 having what appears to be a thinner sleeve than the other cylinders? The sleeves seem to be bored symmetrically. I don't know what the service thickness is for an LS2 sleeve but I do know that .020" over is more than most people are comfortable boring them out to.

 

THey said it was fine and they assured me that .020" would be OK even when I told them my build details and goals.

These are the stock sleeves. GM makes a 0.020" oversized piston so it seems that this is GM's the limit. However, I've read of guys going .030" over with FI and never any problems. I wouldn't want to do that, though.

My concern is that if they knew the sleeves weren't right and it suffered from some sort of core shift, they should have told me and gave me the option to get another block, correct?

 

What you are seeing, is not all to uncommon.
You gotta remember, that the sleeves are cast in place. When they are machined, if the cylinder isnt in the EXACT same location as the others, this is what it looks like.

9 out of 10 factory LS blocks are going to have some sort of this. Especially after they've been machined heavily.

 

Doesn't look like core shift, the thin sleeve looks to be bored in the center of the sleeve right? The sleeve is just thinner. Not sure how normal that is.

 

Bill, I don't think that's what's going on here. The sleeve isn't thinner all the way around. The left side of the sleeves are far thicker than the right.

 

I guess it's not a big deal, I've been advised to run it. I'm just waiting to hear back from the shop tomorrow.

 

OK, maybe I'm not looking at it right. I guess if others say it's OK then it is but I would be leery like you. Next time go iron and you won't have to worry about it.

 

Yeah, I am leery of it, especially at the HP level that I want to achieve. I sent an email to the builder because it was too late last night, so I'll hear something today.

 

Whew....that just doesn't look right. .020 overbore isn't really that much material removed. (1) one hundredth of an inch removed around the circumference of the hole. Even if they took it all from one side, it wouldn't look that bad. I guess that's why they try for minimum overbores. Just doesn't look kosher to me.

 

I agree that 0.020" isn't that much material. I've had opinions from Kurt Urban, Billy Briggs, and Steve at R.E.D. and they all advised me to run it. Granted, they didn't build it and it's not the most comfortable situation, but at this point, I don't really have any other avenues to pursue. Kurt mentioned that it was simply a flaw from GM during the casting process.

The only thing that I wish is that I would have been informed of the issue and been allowed to make a decision.

 

The Core Shift seems excessive . How much power are you trying to make with it ? Na or boosted ?

 

Its a TT car-No drag racing, just Mexico-type runs

Looking to make in the 950rw range

 

IMO I wouldn't use that long block at that power level and feel confident . Especially Mexico long pulls / high cylinder pressure . Think would be a great 600 hp motor

 

Im not sure that you will find a more educated answer on here. If Those 3 said run it, Id stop second guessing, and run it.

 

I noticed the same thing on my block. This started as an alum 5.3L and was bored to 3.905. I then looked at my stock ls1 block and saw it was similar.

To take off so little material and have it end up like that it had to be like that from the factory. Sounds about right. Gotta love GM. Next we can compare body panel gaps to German cars.

 

WTF are Mexico long pulls?

 

Thanks for the reference pic, Joe.