4.0 rebuild

[rage_blue]

So My oil pressure is all of sudden really low, so I;ve decided to do a rebuild on the motor. Can't afford to do a stroker right now so a close to to stock rebuild is what I'll probably do. I think I'm going to get better pistons, probably have the block decked and cyls will likly have to be bored. Maybe even a lite port job. what kind of pistons work well for a mild build? Has anyone run chromolly rings in these engines?

 

[Talyn]

Speed pro makes good pistons and no problem with moly rings.

 

[rage_blue]

Whats a good compression ratio to shoot for?

 

[sardo_67]

http://naxja.org/forum/showthread.php?t=1087751

some good info in that thread. 9:1 comp should let you run regular gas and no need for the more expensive stuff.

 

[Dr. Dyno]

Get the Speed Pro H825CP pistons, have the block decked to zero clearance, and port the head. With a +0.030" overbore and 0.043" head gasket, displacement will be 4016cc, quench will be 0.043", and CR will come in at 9.25:1 (assuming 57cc combustion chambers). You'll need a set of shorter Crower 9.600" pushrods to correct the lifter preload for the block +/- head milling.
Should kick ass and still run on regular gas.

 

[rage_blue]

that piston number is for 96 up, are they a little better design? I think i read somewhere about skirt design?

 

[gradon]

The 825s are metric and the 802s are standard--both will work, just get the matching piston rings. I'm running the 825s in my stroker.