Steve - Race Eng

iTrader: (1)

I had some time today to do some sleeve R&D on an LS2 block I bought a while back from Dave White. I thought I would pass along photos of the interior and some details of same.

The first photo shows the iron liners being machined out of the block. The gray iron liners are roughly .075" thick. About the same thickness as those on an LS6 block. So they can not be bored, just clean up honed around .005".

The second photo shows one cylinder with it's liner removed and the one next to it being machined out.

Third photo shows the aluminum wall being machined out of the block. The aluminum wall in the LS2 is larger in diameter than on the earlier blocks and solid between the cylinders. This obviously because the bore is larger in diameter. The outside of the aluminum cylinder wall is roughly 4.750" vs. 4.600" in the LS1 LS6 blocks.

Next photo shows the empty coolant cavity. What GM has done is raise the floor of the coolant cavity almost .750" higher than the LS1 LS6 blocks. There is less room between the larger aluminum liner and the inside of the block side walls. Result of this is considerably less coolant capacity inside the block than on the earlier blocks. This may or may not be a problem with a really high output engine. The MID sleeve OD will be smaller than the original aluminum wall - same diameter as the LS1 LS6 MID sleeves. That will get the coolant flow back to LS1 LS6 levels. The LS1 MID sleeves will not work in this block because of the raised floor.

Last photo shows the heat generated during the machining process. You can see the steam rising off the cutting tool. Without flood coolant the block will grow and distort during the machining process.

This block is not finished. I was careful doing the machining so I would not ruin it. At this point, the block will be sent out for stress relief prior to doing the finish machine work. Any new block must be stress relieved if one expects the cylinder walls to remain round.

This block was machined to design new LS2 specific wet MID liners but I did gather the necessary info with which to design proper dry liners for the LS2 for those looking for a less expensive alternative. What I propose is a two diameter dry liner, thicker on the thrust walls, thinner at the bottom. This will add strength where it is needed without weakening the block. The upper flange needs to be such that there is a .100" ledge for the sleeve to sit on. Much less than this and the sleeve will drop in service, especially if the engine has a power adder like nitrous or blower. The deck gets pretty hot in those applications, weakening the aluminum. That was the impetus behind the design of the MID wet liner with the coolant channels in the sleeve flanges along with moving the sleeve seating surface to the bottom of the coolant jacket.

Steve

bigeller

iTrader: (2)

Good Info..

DrkPhx

iTrader: (15)

Steve - Does this mean less overall cooling capacity for all LS2 based engines? Or is your concern just for sleeved LS2's?

Steve - Race Eng

iTrader: (1)

There is definately less coolant capacity inside the stock LS2 block than inside a stock LS1 or LS6 block. That means that whether used as is or dry sleeved the coolant space will be smaller inside the block and so will the coolant flow since there is less space for the coolant to flow around the aluminum sleeves.

When we wet sleeve the LS2 we will gain some of the coolant volume back since the aluminum wall is machined out as shown. We will still be short the three quarters of an inch the coolant floor has been raised. That part probably will not be an issue since most of the cylinder heat is near the top of the cylinder where combustion takes place.

Steve

Vents

iTrader: (9)

Steve,

what kind of finished bore can we look to see on a dry sleve application?

Boosted LS1

Good info. I wondered about heat issues with this block, due to the siamesed liners. On our late rover v8's they also joined the dry liners together with a rib but they left a 10 mm gap at the top, possibly for coolant to absorb heat by the deck. This would be the hottest part of the cylinder, above the ring pack.

Mike.

Steve - Race Eng

iTrader: (1)

If the LS2 block did not have the windage holes in the mains we could take it out to 4.200" with a purpose made Darton ductile iron dry sleeve. Problem is a hole offers no support whether it is the LS2 or LS6 block. The block would most likely crack between the sleeves if you went to 4.200" bore.

Simple arithmetic tells us that at 4.200" bore with a .060" wall sleeve thickness at the bottom of the liner, there would be only .080" of aluminum left between the sleeves. We run some of the Honda engines less than .050" but they don't have holes in the webbing.

From experience we know that this type windage hole block will work at 4.160" bore. I would keep that as the safe max. bore on these blocks. That will leave .120" of aluminum between the sleeves.

Steve

Steve - Race Eng

iTrader: (1)

Mike,

You are correct, no coolant transfer passage between the cylinders on the LS2. The LS1 LS6 blocks did have a passage (about an eighth inch wide) running from just below the deck to about an inch and a half down.

We were aware of cooling issues of siamesed bores when we designed the MID wet liners. We machine several coolant transfer slots between the liners on the MID wet sleeves to get coolant flowing between them.

Steve

Boosted LS1

Thanks Steve,

What is the MID wet liner, is MID a brand name? Don't forget I'm in the UK so don't get to see all the US products.

Have you seen into an ls7 block yet? I'm guessing that's also got a raised floor to support the dry liners. Have these blocks ls2/7 had the coolant openings behind the water pump enlarged to the same size as the gaskets? That might help with flow.

Mike.

MrDude_1

iTrader: (4)

4.160?? hmmm.... with a 4"stroke, thats basicly 435ci.... cooool.

just for bench racing laughs, whats teh max stroke that you could stick in there before you absolutly start smacking stuff or grinding too much?

Steve - Race Eng

iTrader: (1)

Mike,

MID stands for "Modular Integrated Deck" which is a registered trademark of Darton Sleeve Company's line of wet replacement liners with coolant groove. I am one of the co patent holders on their line of sleeves. If I can find your e-mail I will send you some photos of the sleeves.

My best guess is the LS7 and LS2 blocks are poured using the same molds. I have no connections to get one of the LS7 blocks to examine.

Regarding the coolant holes in the front of the block. They appear to be the same as the LS6 but the front cylinders are closer to the opening than on the LS1 LS6 blocks because the aluminum cylinder wall is larger in diameter. This would further restrict coolant flow.

To answer another question, I don't like going over 4" stroke on these engines because of the deck height. The longer the stroke, the shorter the piston skirt becomes shortening the service life.

I am condsidering making a deck riser plate if there is enough call for it. That would allow a longer stroke and longer connecting rod to be used as well without compromising the piston.

Steve

jub jub

Great info Steve! So would I be correct in assuming a later LS-1/6 block would be more desireable for Darton wet sleeves?

Scalpel

iTrader: (4)

Yes, sir.

427 LS1

iTrader: (10)

actually the LS1 blocks are the best because they support the bottom of the sleeve 360* whereas the LS6 blocks with their breathing windows at the bottom of the liners don't. Dave

Project GatTagO

iTrader: (7)

Would using Evans Cooling NPG+ be of benefit with a sleeved LS2 block?

Andrew

Steve - Race Eng

iTrader: (1)

The later LS1 block with drilled hole through the main webs is the best block to use for wet sleeving. By late I mean the blocks with cast oil transfer slot at the back between the lifter galleys. The early blocks were flat at the back with the connecting passage in the cover only. The earliest blocks can be modified however so don't throw them out as unusable.

I will do a prototype Darton ductile iron dry sleeved LS2 in a couple of weeks. I'll post the details of the sleeve and installation. The dry sleeved LS2 block is not intended as a replacement for the MID wet sleeves. There is no way to make a dry sleeved block's cylinder walls as strong at 4.125" + bore size. We are doing this to offer a lower cost alternative for large inch non max. effort engines. Figure around eight to nine hundred dollars less than an MID reworked block.

Steve

Steve - Race Eng

iTrader: (1)

The Evans coolant and pump will help out with the deficiencies in coolant volume and flow.

I don't have coolant flow figures for the LS2 block yet to know what the drop is relative to the earlier blocks. I'll see if I can get Evans to get a block and run a flow test. The company I had do the flow testing on the LS1 block has since closed.

Steve

ULTIMATEORANGESS

iTrader: (4)

keep up the good work and research.

JZ'sTA

iTrader: (23)

You could have a real nice build if this happened.
Massive cubic inches without as much risk.
I think it will depend on how much extra it would cost, and may not be worth it.
I am gonna guess most will be happy with 430+ cubic inches.

Boosted LS1

Steve,

Thanks for the help, it's appreciated. There's been a lot of thought put into this and I'm convinced it's the way to go. I'm really worried the ls7 or c5 liners won't stand up to detonation any better then the other lsx thin walled liners. Your thick walled jobbies are pukka and I like the special cooling functions around the deck. I'll send you a block shortly.

regards, Mike.