blown head gasket

[johnkmpf]

has anyone had problems with blowing a headgasket on a 440 high compression kit? when engine is cool I can feel and hear a compression leak at the gasket. I'm wondering if the headbolts may of streatched or loosened. The motor is fairly new(3 mo.) and I also run it fairly hard. I'f anyone had and similar issues please let me know. Also i need to know what the correct torque for the head bolts...thanx

[patches85]

I don't know from experience but I think this is an issue with 440's. Install oversize headbolts and a new head gasket. Should fix it.

[GPracer2500]

The head studs like to pull out of the head on high compression pistoned 400EXs. It's a fairly common problem.

Heavy duty head studs are the solution. They are thicker with larger threads. The new threads in the head must be roll-tapped for strength. A standard cutting thread tap defeates half the benefit of the HD studs (so I've been told).

[cals400ex]

well there is no way i would have put that head on without knowing the torque specs.....i think it is around 34 ft-lbs if i remember correctly.

[GPracer2500]

Plus, head stud nuts should be re-torqued after several (maybe 5-10) hours of use.

ETA: service manual specifies 33 ft-lbs for the head nuts.

[Colby@C&DRacing]

Originally posted by GPracer2500
Plus, head stud nuts should be re-torqued after several (maybe 5-10) hours of use.

ETA: service manual specifies 33 ft-lbs for the head nuts.

only if you are using a composite gasket do they need retorqued and if you are running a high compression piston the torque specs should not be stock specification. They should be 38ftlbs

[johnkmpf]

thanks for the input, i will put new hd head bolts in

[GPracer2500]

Originally posted by Colby@C&DRacing
only if you are using a composite gasket do they need retorqued and if you are running a high compression piston the torque specs should not be stock specification. They should be 38ftlbs

I prefer to retorque reguardless of gasket type. Waste of time?? I suppose that's arguable but I was taught to retorque head studs after any engine rebuild reguardless of gasket type or engine type.

I figure it can't hurt...:)

[Glamis400ex]

Colby,

Are you serious about the 38 ft/lb torque rating on HD studs and hi-comp piston? When I had my HD studs put in by FDO Racing, they told me to torque the nuts to 33 ft/lb. I haven't broke my 426 in yet but I wonder if I should take off the head and re-do the nuts to 38. My 416 and flexsteel gasket was set at 33. I developed a leak but that was due to the sleeve dropping a tiny bit.

Since they are currently at 33 could I just set up my wrench to 38 and go for it or do I need to loosen all of them and then go gradually to 38?

Thanks,

Glamis