Increasing HorsePower -- What You Need To Know

[Rawze]

rod/main bearings look that engine has had a hard life but I have seen worse.

No need to try to modify anything, you are over-thinking it.

All genuine cummins parts, Counter-bore it and raise the liner height to 0.014" on all cylinders while your in-framing it, new oil pump with 6 - 8 dimes shimm in the springs, better programming. if the head is more than 450k miles old, throw it in the trash and buy a brand spanking new one,... not re-man.

When you do the 300-ft lbs on the head bolts, let it sit overnight 24 hours. Then the next day, re-torque to 300 ft lbs again a second time. Most of the bolts will go another 1/4 - 1/2 turn... After that, you should take them the other 90 degrees for the final setting like the book says.

Make damn sure you measure those wrist pin bushings on them really well. I think cummins spec has it as being min 2.5020 max 2.5030. When they are 0.001" out of spec, the engine will only last half million miles and might throw a piston, at 0.002" out of spec, engine will only last 250-300k miles, and at 0.004" it is a time bomb. <<- bad deletes are notorious to make the wrist pin bushings get out of round.


Head is the weak point on them, not worth trying to save it, or put a re-man on it. you will be pulling it off in another 250k miles if you try to save money on it. Take that advice on someone who has seen it too many times.