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View Full Version : Cylinder heads water leak...help !!



DonZi 26
05-04-2011, 04:12 PM
my engine has two brand new dart iron eagle cylinder heads....after a couple a runs i can see traces of water leaking down the block from the exhaust side. The leaks are coming from where the head seals on the gasket, and i can see small leaks down the block....

the heads have been torqued at 70ft lbs and have also been double checked....

i just wanna know if this is normal since they are brand new and would they stop after some time....or what would be the best solution ?

your input would be greatly appreciated!

mrfixxall
05-04-2011, 04:16 PM
my engine has two brand new dart iron eagle cylinder heads....after two runs i can see traces of water leaking down the block from the exhaust side. The leaks are coming from where the head seals on the gasket, and i can see small leaks down the block....

the heads have been torqued at 70ft lbs and have also been double checked....

i just wanna know if this is normal since they are brand new and would they stop after some time....or what would be the best solution ?

your input would be greatly appreciated!


re torque them to 85 and keep repeating until they are all the same torque..you cant just torque them once because after you torque the head bolts it changes the quench between the bolts..

DonZi 26
05-04-2011, 04:30 PM
re torque them to 85 and keep repeating until they are all the same torque..you cant just torque them once because after you torque the head bolts it changes the quench between the bolts..


that is what i did after two runs...

would it be the best solution to take the heads off or should i try an re-torque them again ?

MOP
05-04-2011, 04:37 PM
85 is to much way above book spec which is 65, on a Chevy you can pull the threads right out of the block. Yes depending on who's gaskets you used they may have needed to be re-torqued after it was brought to temp! What you may experiencing is too much water pressure, head gaskets will only tolerate about 35lbs. It is very common for the gaskets to weep on raw cooled engines, I would guess that 25-30% of the raw cooled boats I have serviced weeped somewhat, the newer better gaskets hold better but still not up to high pressures. Phil

DonZi 26
05-04-2011, 04:42 PM
mop;

i wouldnt know what kinda water pressure i have, but i have a stock mercruiser sea pump, crossovers with the s/s thermostat housing and the i use the boat in salt water....

MOP
05-04-2011, 04:56 PM
@ idle you probably have 15-20psi, @ high speed it can go way up, Griz stated he had seen around 80psi running hard. Many do not realize how the pressure builds at speed, at work during bay testing I have watched circ hoses expand as speed increased. Merc sells a pressure relief valve, I believe it is still a little high @30psi. I have followed many threads on this and several other boards 20psi is adequate, that figure came from guys with some major HP. A few of the guys up on Boat Freaks made up their own relief valves knowing the Merc's were to high, one fellow even made his adjustable.

silverghost
05-04-2011, 05:42 PM
MOP is correct about the high pressure issues.

Are BOTH heads weeping ?

What brand & type of head gaskets are you using ?
Some seal much better than others~
Some are only for automobile use; & do not seal very well in marine raw water usage.
Did you use any sort of head gasket sealer such as copper-coat spray ?

mrfixxall
05-04-2011, 06:10 PM
85 is to much way above book spec which is 65, on a Chevy you can pull the threads right out of the block. Yes depending on who's gaskets you used they may have needed to be re-torqued after it was brought to temp! What you may experiencing is too much water pressure, head gaskets will only tolerate about 35lbs. It is very common for the gaskets to weep on raw cooled engines, I would guess that 25-30% of the raw cooled boats I have serviced weeped somewhat, the newer better gaskets hold better but still not up to high pressures. Phil


if it were a small block i would agree with you but the manual reads 85..

this came from a 1993-1997 454-502 manual,,i went through 1997 -2001 and it read the same specs..if your running head studs then subtract 10 lbs.
done lots of BB's and never pulled a thread out of a block @ 85 lbs.

MOP
05-04-2011, 09:28 PM
if it were a small block i would agree with you but the manual reads 85..

this came from a 1993-1997 454-502 manual,,i went through 1997 -2001 and it read the same specs..if your running head studs then subtract 10 lbs.
done lots of BB's and never pulled a thread out of a block @ 85 lbs.

My bad I am a SB freak!

mrfixxall
05-04-2011, 10:26 PM
My bad I am a SB freak!


Mop i may be wrong also,,he never posted the engine size:wink: