no compression

[hungryjoseph]

I replaced my head gasket after over heating and blowing the first one. The temps shot up pretty high but it was during idle. I didn't know how high the temps were cus I ran inside to take a poo and came back to find it sitting above 250. I find out later that there is coolant leaking through between the head and block around cyl #3, I did a compression test and saw that it was 55psi, while the rest were 145 - 150. I poured a cap of oil and it bumped it to 60psi, not enough to point the finger at the rings so I assumed it was the gasket based on the coolant leaking outside from the head and block, and the low compression on the cylander that was next to the leak.

I got the head resurfaced, new valve seals, guides, hot tanked, got an apexi metal headgasket, stock size, put it on, torqued it down with arp studs, got it mounted in the car, my battery drained out so I cranked it over by hand to see if compression was somewhat ok, and I got 60psi on the cyl's except cyl #3, which gave me like 10psi no matter how hard I turned the crank. I understand that turning it by hand is inaccurate but a 50psi difference tells me something is wrong. what would it be? crack in the head?

[jr_ss]

You would've been able to see a crack in the head, especially if you had it hot-tanked and cleaned up. I'd crank it over with the starter and see what you have, cranking by hand is no way to make compression.

[hungryjoseph]

I guess I made this thread for an ease of mind sort of thing. I've spent some money getting this headgasket done and that 3rd cylinder still scares me. You don't think it's odd that it will build little to no compression while the other cylinders are at least 50 - 60 psi? I've done this on other motors and they usually come out with similar numbers when cranked over by hand, I've never had such little before

[jr_ss]

It definitely raises a flag, but the only way you can really tell is cranking it under the force of the starter... I'm not sure what could cause that, unless you have a bent valve or the valve seat is leaking..

[CSUPUEBLOTIM]

So after all this your other cylinders are now showing only 50-60psi when before they were 145-150???

[hungryjoseph]

well its 50 - 60 cus im cranking it by hand, which isn't too unusual, but I will find out in an hour after this battery is charged

[the converted]

So you didn't check the rings did you.....

[hungryjoseph]

bleh I drove all the way to the garage to find out I didn't bring my key... so I couldn't crank it over after I brought a good battery.

No, I didn't pull out the pistons and check the rings. I did pour oil in there and it bumped it up a few psi before I installed the headgasket, when the motor first went bad.

[hungryjoseph]

blew a piston ring I think, did a leak down test and had air coming out of the crank case and valve cover