Question on the piston block height... it appears the LS3 deck height is 9.24 +/- a few thou...

SRP 9.251 / -5cc / 4032 / $499
Mahle [not listed] / -4cc / 4032 /$630
Wiseco 9.24 / -2.8cc / 2618 /$753

Does this seem to indicate the Wiseco should be flat with the deck (everything being perfect which it never is) and the SRP would be out of the hole .011?

I prefer the SRP & Mahle because of the 4032 alloy for my application, and prefer the SRP over the Mahle because of the cost savings outweight the minor compression increase. So that would still be .040 quench. But if we do a cleanup mill on the block to insure it's straight, that could possibly put me on the verge of a quench distance which is too low. The same cleanup wouldn't affect the Wiseco piston as much...not sure on the Mahle because they don't list a deck height.

I guess I just can't buy head gaskets until (if) the deck is cleaned so I know how much they are out of the hole, then pick a gasket which gets me near .040 quench and a head mill which gets me in the upper 10's for SCR.

 

What's wrong with using a stock MLS gasket? (.049-.052 crush)

 

I assumed the stock gaskets were still graphite because the original LS1's were. If the LS3 stock gasket is MLS and thus doesn't require scraping the heads upon future removal, that's a plus. I'm sure they're less expensive than a Cometic, that's another plus. My only questions are 1) does the LS3 deck need a cleanup mill to insure the compression in each chamber is the same, 2) if yes, will the mill put the piston too close to the head and make the squish/quench too tight? 3) if no, then I just need the LS3 stock head gasket part number (which I haven't been able to find).

I haven't been able to locate the 2005+ timing gear part number(s) nor the LS3-specific chain dampener part number.

 

I just grabbed one from the garage, its the MLS from the 2010 SS and has no part # on it. LEss expensive than a cometic for sure, I remember from 40-80 for the pair.

Which are you talking about for a cleanup mill, the block or the deck? Neither should "need" anything, you just ususlly end up cutting something to put all the parts exactly where you want them.

I assume youre talking about the SRP pistons and the supposed .011 + height? I doubt that's the case as the factory pistons are .007+ and every single engine Ive ever built needed the deck cut to get the piston out of the hole. There's always a first time, but you dont know until you pre-assemble the short block.

 

Looks like it's

#12610046 -LS3/L92 GM MLS Head Gasket SOLD AS A SINGLE

Found them new for $23.87/ea through GMPP. I was talking about the block mill.

rod bolts: ARP std or 2000?

SDPC said if we're using the 24x reluctor, then the normal timing gear/LS2 chain will work. Just want to confirm that I didn't describe the situation incorrectly.... so will my LS1 timing gears and my LS2 timing chain migrate to the LS3 correctly using the LS3 timing chain dampener? Even if they do fit, is there reason to replace them anyway?

 

It might need a cleanup, it might not. That's something you find out when the engine comes apart. These questions are ones that we can't really answer for you until you do some measuring. For all I know, the engine could have been severely overheated, and the block needs .010-.020" cut to get it straight and perpendicular again. That's probably worse case scenario.

More than likely, the deck is fine, and could use a minor .002" cut to clean it up, but it's probably not necessary. More than likely, the GM MLS gasket will work great with the SRP pistons. If however, you find that it doesn't, and you don't have enough quench, the pistons can always go in a lathe to take a few thou off.

 

I'm pretty sure Jim is using a new GM LS3 block, so it shouldn't need a mill. Most blocks however end up getting cut at least a little to set the deck height correct with aftermarket rods/pistons.

+1 on shaving the pistons. I've run into not engough deck height a few times. You can either shave the pistons a few thou or get a custom Cometic gasket a little thicker.

 

LS3 motor finally on the k-member last night. Hope to have everything buttoned up today.

 

Sweet.
Man you pulled that together reel quick.Good job.
So, what are the final specs on it. (size,cam etc...)
You have got to get us start up videos.

 

In general, 377 LS3, stock LS3 heads millled .030, 222/230 LSR cam from EPS, SCR 10.9:1, DCR 8.6:1.

 

Got the car back, but have some issues to clean up before I can drive it ...

- P107 (MAP low voltage) - causing major surging because MAP stays at 10kPa
- P343 (Cam sensor high voltage) - causing big problems attempting to start the car

And a couple of non-drivability issues...
- Fabricate permanent throttle body bracket
- Need header wrap to protect driver side knock sensor wiring
- Repair thin tube which is supposed to connect to back of intake
- Install racetronix fuel system upgrade
- Re-install center console