Head Gasket Bad?

[HoleshotKFX400]

Earlier i posted that my overflow was overflowing... I think i figured out why. When I start the truck i have bubbles in my radiator... so i figured id compression check the cylinders. I pull the spark plugs out and all of them have a greenish yellow tint coated on them.
The cylinders read:
1- 165psi
2- 190psi
3- 160psi
4- 180psi
5- 170psi
6- 180psi
7- 170psi
8- didnt check, steering shaft in my way
So do you guys think thats the head gasket thats bad?

 

[baddad457]

If you've got bubbles in the coolant, pop the radiator cap back on for a few seconds and rev it. Then try to remove the cap, if the gaskets are blown, there will be pressure in the system after a few seconds.

 

[HoleshotKFX400]

Yeah there is, i forgot to include that. When I buy head gaskets what kind do you recommend + i cant find any for 4.040 bore? thats the ones i would go with because my motor is bored .040 right?

 

[almostclueless]

Quality head gaskets will usually accomodate any reasonable overbore.


An air hose and fitting for the spark plug hole will find which cylinder is leaking into the cooling system. It could be a head gasket or a crack in the head or block.

 

[HoleshotKFX400]

So do you think that i could use just 4.030 gaskets... and that 10 thousands wont make a difference?

 

[almostclueless]

I meant that usually, the majority of head gaskets avaliable have openings that are around .060 larger than the stock bore size unless the manufacturer actually states they're for really larger bores.

I've never built an engine where I had to worry if the overbore necessary to rebuild it exceeded the bore of the head gaskets.

 

[Mac]

Just measured a FelPro 1011-2. It goes a 4.105" dia.
Dave

 

[baddad457]

Best gaskets are Felpro's expanded graphite, these are the stock replacements, the comprssion rings are big enough to accomodate 4.1 bores, as are all the SBF gaskets.

 

[HoleshotKFX400]

Thanks guys thats what i got today, just the felpro replacement jobs, along with all the other gaskets that ill need for this fun feat

 

[stranger]

it sounds like a blown intake gasket not a head gasket.judging from your comp#'s

 

[HoleshotKFX400]

I think im just going to replace the headgaskets anyway... i wanna see how the pistons & piston walls look + i might put some roller rockers on and a new cam

 

[wade]

it sounds like a blown intake gasket

If you're replacing head gaskets, it almost a given that the intake will get changed, TOO! Well?