compression in the cylinder

[CaEric]

wen doing a compression check what should the compression be in each cylander and whats the safe limit

[knightrider]

i dont have my fsm infront of me, but 150 is a good number,

[c-rad]

I am pretty sure 162 is the rebuilt/new specs and 125ish is the service limit.

[float_6969]

LOL, I got 180 on my rebuild. <1% variation. The guy that built my engine does ProStreet and builds his own 1500hp+ motors.

[capowered240]

171psi is standard. 142psi is the minimum. Anything under 142 you should rebuild. There should only be 14psi between cylinders. Someone correct me if I'm wrong.

[boost_boy]

171psi is standard. 142psi is the minimum. Anything under 142 you should rebuild. There should only be 14psi between cylinders. Someone correct me if I'm wrong.

It can be at 120psi per cylinder, as long as there's not more than a 10psi difference between them and if it's not spitting up oil or giving you driveability issues, I would leave it alone. Just keep an eye on it!

BTW, I drove one of my engines with only 90psi per cylinder and it drove great, but had horrible vacuum at idle (With upgraded cams) which sucks. But no smoke, no oil consumption, and 15-20psi of boost fun without worrying about detonation. But please don't take my word for it and don't follow what I did. I eventually had to correct this issue which had something to do with the head and not the bottom end components.

Dee

[capowered240]

Ok, I got my info off the the fsm. Damn that's pretty low compression.

[sideways danny]

It can be at 120psi per cylinder, as long as there's not more than a 10psi difference between them and if it's not spitting up oil or giving you driveability issues, I would leave it alone. Just keep an eye on it!

BTW, I drove one of my engines with only 90psi per cylinder and it drove great, but had horrible vacuum at idle (With upgraded cams) which sucks. But no smoke, no oil consumption, and 15-20psi of boost fun without worrying about detonation. But please don't take my word for it and don't follow what I did. I eventually had to correct this issue which had something to do with the head and not the bottom end components.

Dee

worn inlet valves Dee?

[boost_boy]

worn inlet valves Dee?

I don't know Danny, but it was in the head. The issues I usually face is either low oil pressure (with new internals) or the last one I battled was the compression. When I changed the head, the compression went from 90psi per cylinder to a whopping 150psi per cylinder and this was a stock/junkyard head. I am using that same suspect head now with different valves, springs, guides, and cams and the compression on the customer's new motor is 160psi per cylinder.

The Low oil pressure stuff sucks big time. There's a gang of faulty pumps or something out there.

Dee