s2pdfst_z06

As the title states, anyone know if the LS7 block is repairable? The sleeve on cylinder #5 is cracked and there's a crack on the lower left corner of the cylinder wall.

0HorsePowerAddicts

I would not use that block. Its not just the sleeve. It looks like the water jackets are damaged badly.

Z Fast

I'm pretty sure the LS7 can be resleaved, but the picture you provided shows damage to the block and I'd say it is now one big paper weight.

Gannet

That block would require a lot of welding before it could be resleeved. It's not worth it, either in time/money or risk. Sorry about that.

NORTY

Buy a glass table top since you have a base...

dfinke23

It may be salvageable. Darton makes a MID (modular integrated deck) sleeve that removes the water jacket completely; coolant flows through ports in the sleeve flange and contacts the iron sleeve directly. It costs about the same as a new LS7 block, but with ductile iron sleeves (vs. stock grey iron) you get LSX type strength and you can go up to a 4.200 bore. Call Steve at Race Engine Development (760) 630-0450 and send him some high res pics, he'll be able to tell you if he can fix it.

s2pdfst_z06

I'm just trying to get an idea if I should try to sell it as a cracked short block, or salvage the crank, connecting rods, etc. and take the block to an aluminum recycler.

tjwong

There has been issues with using the MID system. Mainly head gasket integrity and water containment. It is imperative that the block prep is correct and that the sleeves are installed correctly. If any one can do it then its Steve. I have seen two of them fail here in my area. Both were 4.125 bores, one a 427 the other a 377, both made great power normally aspirated but they couldn't keep headgaskets in them. To me it appeared that the sleeves moved and then compromised the gaskets.

dfinke23

... the one downside is that you have to use Cometic gaskets. We used copper coat, torqued to specs, heat cycled and re-torqued; so far zero issues.
Bowtiguy had problems with the "dry" sleeves moving; where the two that you saw MID or dry sleeves?

tjwong

Both are MID sleeves. I have two engines (including mine) one is a TT car making in excess of 800whp, mine is the same build but isn't in the car yet. Plans are for a FI application about the same wheel power. So far so good no issues with the one running and the owner runs it hard! I also use copper coat although Cometic doesn't recommend it, if I don't use it I have had leaks, everytime I have used it no leaks. I have since gone to OE GM MLS gaskets, I have never every had a leak with them and I don't use any kind of sealer on their gaskets, the main thing is that I make sure the surfaces are clean.

dfinke23

Did Steve do the MID sleeves on the two that failed?

kelp

I would recommend Steve, he did my block with Darton sleeves. How much is Aluminum per pound?

Vito.A

It is difficult to tell if this is repairable by looking at the picture. You need to finish taking it apart and take it to a reputable shop for inspection. Generally, if the mains and water jackets are intact, it is repairable. If they are damaged, it gets into the that depends category. They can still be repaired, but it rapidly gets more expensive than buying a replacement block.

I can see pieces of piston still in the bottom. Looks like another cast piston bit the dust. Did a valve come loose first?

Best of luck!

tjwong

I am not sure its been some time ago. I am pretty sure one of them was done in Texas somewhere, not sure where the other was done. I know Steve is in California so I don't think it was him. He has done two sleeve jobs for me recently but not the MID system.

s2pdfst_z06

It's about 0.90/lb here.

s2pdfst_z06

Exhaust valve head came off.

tjwong

Seen that one once too many:








It ain't pretty!

OregonC6

Wow, that's a very very sharp solution to resleeving this block. Somebody had their thinking cap on for sure.

JDMUSCLE

Wondering what is the number 1 cause of an LS7's failure.... Is it power or poor tuning? Few LS2 owners always complained of the cylinder#7 running hotter than others due to fuel starvation... LS7 do have the same fuel setup (returnless design).

Can you please explain the failure you have experienced in further detail.. And what mods were done at the time of failure? Thank you in advance for your feedback....

As far as salvinging this block.... IMO... I wouldn't due to extent of visible damage and who knows all other areas that are stressed due to this failure that is not visible to the naked eye. Go the LSX route and you will have a piece of mind and a crap load of power...

dfinke23

The LSX was too heavy for me, in all of the wrong places.