3rd gen 3S block, The "Cracking issue" Options

[Alan]

Hey guys I am currently building a 3rd gen 3s engine and my only concern is the block cracking problem my Block is a 3s 1996 block it is the thicker reinforced block.
I am aiming for big HP (850WHP), but this block roumors are getting abit to old everyone says different thing about it use sleeves dont use sleeves use Hardblok dont use it, leave the bore standard... alot of mislead info

Can anyone out there share with me what I should be doing with my block should I sleeve it or not the bore I am going for is 86.5mm I have had someone tell me its not safe to go above 650 with this bore this person uses sleeves and has no probs but I have other freinds stating that the sleeve will still crack so basically I dont know who to belive .

I have spent thousands on parts I dont want it all to go to ****s after all this money spent only weak spot i found is this block issue so please anyone out there running big hp on a 3S share with me what I need to do.

Also I would like to use the 3s block I dont wanna use the 5s!!!

[Bitter]

From memory it's because of thermal stresses caused by boiling between cylinders 2 and 3 due to the very very narrow coolant passage. Higher cooling system pressures, non boiling coolants, etc can help, as can meth injection.

[Special_Edy]

From memory it's because of thermal stresses caused by boiling between cylinders 2 and 3 due to the very very narrow coolant passage. Higher cooling system pressures, non boiling coolants, etc can help, as can meth injection.

Then using a block filler would be even more effective. By filling the bottom of the water jackets you are removing a significant amount of volume from the coolant system. The vast majority of the heat is going to occur at the cylinder head and the top of the cylinders where the combustion occurs, not the lower 2/3rds of the cylinder. By filling in the water jackets you are increasing flow of coolant through the block, thus running a cooler engine.