Paul Bell

iTrader: (9)

Just trying to gain some more knowledge here and there seems to be nothing posted -yet.

The LS7 block has pressed in cylinder sleeves. Are these sleeves easily replaced?

Exidous

iTrader: (11)

Can they be? Yes, easily....not so much. A professional needs to do it. I think ERL does all 8 for ~$1550. They refinish the block and put in thicker sleeves.

Paul Bell

iTrader: (9)

Thank you sir. Anybody else?

NOW something comes up when searching for "LS7 sleeves"

Exidous

iTrader: (11)

HAHA no problem. You probably could do it yourself with a press but to really do it right without stressing the block improperly I'd go ERL or similar all the way. Been debating an LS7 or boost for a while now....

87silverbullet

iTrader: (11)

RED does them also out in Oceanside, CA.

BattleSausage

iTrader: (3)

There is a big difference in the stock vs aftermarket. The stockers can have the block cast around them, creating a perfect fit and essentially freezing the sleeve in place because all the imperfections are filled by the casting and don't allow it to move. To replace it, you have to create a near perfect interference fit, hence the need for a CNC to perfectly duplicate the measurements needed. Not only that, the block needs to be stress relieved before and after. I believe that do it correctly also have a system in place to keep the block at proper temp before allowing it to return to room temp once done, thereby allowing it to effectively clamp down around the new sleeve. Kinda like freezing a new press-fit bearing before installing it so once it cools it expands and becomes a perfect interference fit. Plus these new wet sleeves require some type of thread locker/sealant. Not rocket science I assume, but very strict tolerances and strict procedure must be kept to ensure a long lasting end product.

I will say that it isn't impossible to do manually, but the perfect alignment needed makes it so much easier with a digitized CAD file so that the CNC can perfectly bore out the old material and center the sleeve correctly. Especially all blocks have some core shift to some extent. Pretty much just takes out the guesswork and human error that inevitably WILL happy at some point.

SOHCNightmare

Seems like it'd be cheaper, and easier to go with an Iron block, and not worry about this. Unless you're concerned about weight...

Steve - Race Eng

iTrader: (1)

Darton makes both wet MID and dry Seal Tight liners for the GM alumimum blocks. Either style will fit the Gen IV blocks. The Gen III are MID only because the blocks are not siamese bore as are most all Gen IV blocks.

The LS7 blocks have pressed in gray iron liners unlike all other Gen IV blocks, LS2, LS3, 5.3 truck, etc. that have cast in gray iron liners. It is however not possible to simply press out the LS7 liners, they are machined out in my case. The only other method to get them out is to run a weld bead vertically in the sleeve which shrinks them enough to loosen them for removal.

The Darton Seal Tight ductile iron sleeves are roughly four times stronger than the gray iron factory liners. They will not crack like the factory sleeves.

You do need a CNC with flood coolant to install the dry or MID sleeves. Tolerances are tight (+- a half thou on bore spacing) to achieve a perfect job.

I also vibratory stress relieve the blocks (they are not heated) during and after the machining process to stablize them so they don't distort when put into service.

Steve

Paul Bell

iTrader: (9)

Thanks for that. We now have some good searchable info regarding the LS7 sleeves.

This expands the available information here on LS1tech.

S10xGN

iTrader: (11)

I must have missed it... So, it's impractical to expect a local shop to replace the liners in an LS-7 block? Does anyone even sell a drop-in replacement that's not gray cast iron? I ask because I occasionally see one pop up on E-Bay with a bad liner or two. From what I'm getting here, it's better to pass and start from scratch with a standard LS block fitted with Dartons...

cmac06

iTrader: (16)

Or get any Aluminum Gen IV block, and have ERL or RED machine out the sleeves and replace them with Darton sleeves. I don't see where you're going to get one with Darton sleeves any cheaper than providing your own core.

427zm

iTrader: (9)

Emailed you Steve...