Resolved Differences between 4g63 and 4g63t? [Merged]

[bbechtel16]

Can anyone explain to me the differences between the NA and the turbocharged 4G63 motors? The NA in question is a '91 and the turbos in question are a '90 and a '91. Thanks in advance for the help.

 

[joat09]

U could drill a small hole through the rod bearings and the caps. That would expell more oil onto the walls to help cool the pistons. I've heard of it being done on other engines. I have not heard of being done successfully on a mitsu engine.

 

[dsm-onster]

There are already holes in for that. And if you drill them through the cap then the oil would be squirting down. There's a hole in the base of the rod facing up toward the piston.

The cracking pistons is one issue independent from not having oil squirters. The n/t 9:1 pistons have ringlands that are too close together for the high cylinder pressures typically seen when you turbocharge the block. Though I can see how one would think they both are related: n/t pistons crack because there's no oil squirter. However, the n/t block I put in my brothers car has seen all a small 16g can throw at it and it still has not cracked a piston; I swapped in turbo pistons.