Head gasket?

[star73]

How much boost will stock HG's hold? I'll be doing DIY 250cc hybrid injectors and a Garett BB. I don't really want to do studs now. Thanks in advance.

[strokin_early_99]

Stock head gaskets and head bolts are good for 40psi. Anything over 40psi and you are really playing with fire.

Stock head gaskets and head studs are good for anywhere between 55-70psi depending on who you talk to. Elmo was running 65psi with two stages of nitrous for 35,000 miles and finally blew the gaskets a little while back. Others say that 55-60 is pushing it, so it depends on who you talk to.

I have been hammering on it with 51psi for the last 3 months without any problems. I don't intend on making any less boost, in fact next week will hopefully up it a little with live tuning.

[bigwhite7.3stroker]

I was wondering also thanks for the info

[CSIPSD]

You will be playing with fire at 250cc and stock bolts... I was at 38-41#'s with 225cc hybrids...

[PSDfan99]

Howard, you have been hitting 51psi on a regular basis with stock studs?

[Marty]

Originally Posted by PSDfan99

Howard, you have been hitting 51psi on a regular basis with stock studs?

I'm pretty sure he's studded on stock gaskets.

[star73]

So if I have to do studs does the cab need to be lifted or is it a in the truck job?

[strokin_early_99]

Stock bolts at 51psi? Are you out of your ever living mind? That would be insane. I have H11 head studs with stock head gaskets, 160K when the studs went in.


The studs can go in with the engine in the truck and the cab on the frame. You will need to take the motor mount bolt out for the side you want to lift and the transmission cross member bolts out. In addition you will need to take out the two 8mm bolts that hold the fan shroud in place on the radiator. Then put a chunk of 2X4 between the frame and engine and lift on the exhaust manifold with the 2X4 on a floor jack. You will also need to take off the evaporator cover on the passenger side.

It is easy only very hard on the ol bod. I hurt for three days afterwords. You need to get in some weird positions to get 145ft-lb final torque.

[PSDfan99]

Originally Posted by strokin_early_99

Stock bolts at 51psi? Are you out of your ever living mind? That would be insane. I have H11 head studs with stock head gaskets, 160K when the studs went in.

In short..... YES, I am slowly going out of my mind! Mostly due to my truck and how it runs as of lately.

fyi people, its not the boost that kills the headgaskets its cylinder pressure. Lots of things cause the pressure to be higher than stock. Timing, amt of fuel being injected, propane, nitrous, water meth, etc... I lower the compression of my engines to help drop the cylinder pressures and run stock gaskets.