87-92 Block Differece 7m-gte

[AllStreet]

I know that '87 7m-gte block is different from the '91 What is the difference i hear one is stronger thanks,.

 

[Nick M]

Well, the one who posted the pics of the later block also noted they have more core shift. So have the machinist check it if you rebuild. You can't sleeve it.

 

[Doward]

Late model blocks have stronger main webbing, extra rib bracing around the block, and 2-3mm more meat pretty much everywhere.

IJ. has pics.

 

[shaeff]

Here are IJ's pics, I have them uploaded in my Photobucket acct. Click to enlarge:

pre '90 block, thinner walls as mentioned, and less bracing:




'90+ block, with extra bracing/ribbing:

 

[Tgood]

Well, the one who posted the pics of the later block also noted they have more core shift. So have the machinist check it if you rebuild. You can't sleeve it.

Actually you can sleeve a 7m block. I didn't think you could until one of my buddys did it to a 7m. He only had to sleeve one cylnder though. He sleeved it because the guy couldn't afford to buy another block so they sleeved the one cylnder.

Edit: forgot to mention that this motor wasn't going to be for a high hp application it was just a factory rebuild. The build thread is on here actually. Gtsfirefighter's block is sleeved and his motor was built by a guy that knows his stuff.

 

[gtsfirefighter]

Actually you can sleeve a 7m block. I didn't think you could until one of my buddys did it to a 7m. He only had to sleeve one cylnder though. He sleeved it because the guy couldn't afford to buy another block so they sleeved the one cylnder.

Edit: forgot to mention that this motor wasn't going to be for a high hp application it was just a factory rebuild. The build thread is on here actually. Gtsfirefighter's block is sleeved and his motor was built by a guy that knows his stuff.

I actually could afford another block but opted not too because I couldn't find one in any better condition, that was local. The cost to sleeve that one cylinder was about the same as buying a bare block. After riding in a 2JZ TT powered MKIII the other day, I might be rethinking my power goals. My block should be good for whatever I might desire, which won't be that much.
My block is an 87 GTE BTW

 

[Nick M]

You can't cut more than 2 thousandths off the block either, when in fact you can. So the idea that you can sleeve it is bad info being passed.

 

[gtsfirefighter]

I've got one sleeved cylinder and am only looking for 300 hp. We'll see how it holds up. It runs really well now but I've only driven it up and down the street a few times. x::crossesfingers::x

 

[Tgood]

I actually could afford another block but opted not too because I couldn't find one in any better condition, that was local. The cost to sleeve that one cylinder was about the same as buying a bare block. After riding in a 2JZ TT powered MKIII the other day, I might be rethinking my power goals. My block should be good for whatever I might desire, which won't be that much.
My block is an 87 GTE BTW

Sorry ken I didn't mean to put you on the spot like that. I knew you couldn't hold out and not put some power down. Lol I plan to do somthing similar.

 

[John_Travolta]

I know that the 90+ block have oil injectors - they spray oil on the bottom of pistons.

What about differents in Cylinder Head?

 

[IJ.]

You CAN sleeve a 7M but it totally destroys any torsional rigidity that the block has making it useless for a performance application......

 

[j3pz]

I know that the 90+ block have oil injectors - they spray oil on the bottom of pistons.

no the turbo models have the oil squirters.

 

[89whitepkg]

so, is the fact that I'm using an 88 block going to be a problem when I start trying to put down some serious numbers?

I'm not talking about the setup.....the only factor being considered in this question is 88 block vs 91 block, are there any extra steps that need taken?

 

[IJ.]

no the turbo models have the oil squirters.

Genuine Group A blocks have no squirters and are based on a Heavy NA block.

so, is the fact that I'm using an 88 block going to be a problem when I start trying to put down some serious numbers?

I'm not talking about the setup.....the only factor being considered in this question is 88 block vs 91 block, are there any extra steps that need taken?

Check it very carefully for cracks in the deck, the above pic was an 87 with 18000 miles and had a bunch of cracks between the head bolt holes and the steam holes.

 

[j3pz]

Genuine Group A blocks have no squirters and are based on a Heavy NA block.

when you say heavy, do you mean one with more ribs/bracing? wonder why they didnt use any squirters.

Check it very carefully for cracks in the deck, the above pic was an 87 with 18000 miles and had a bunch of cracks between the head bolt holes and the steam holes.

do you mean 180,000 or 18k?

 

[fiyota]

I remember reading somewhere that there is a possibility for the squirter's to fail resulting in a loss of oil pressure?

Someone correct me if I'm wrong.

 

[jdub]

The squirters function at ~40 psi...if one or more stick open, yes you will have a loss of pressure.

 

[IJ.]

when you say heavy, do you mean one with more ribs/bracing? wonder why they didnt use any squirters.




do you mean 180,000 or 18k?

The NA blocks went to the heavier/thicker casting before the GTE blocks did.

It's only a guess on my part but I'm assuming they placed a higher priority on more Oil volume to the bearings than in keeping the engine cool, they ran fully grooved mains as well.

18K as in eighteen thousand miles so barely ran in

 

[jmanbball]

Im guessing that they relied on a fairly rich fuel map to cool the pistons.

 

[TurboWarrior]

oil squirters were on late model turbos. either 90+ or 89+. They werent on 87-88 turbos I know that much. My motor is a 7mgte rebuilt there were no squirters when i took it apart.