99purplecummins

whats the MAX boost a stock engine can handle after having the head o-ringed????? there is someone in town that doesn't believe me so i wanna ask to be sure i'm correct. this includes single turboes and twin turboes.

DavidTD

I don't kow if there is a &quot;number&quot;. My experience has so far shown me that 70psi still holds but other factors such as timing, drugs, etc will have direct impact of this too.<br><br>There are plenty of trucks out there way higher than this...

PourinDiesel

With a good set of properly torqued head bolts and a stock gasket, I think 50 psi should be ok.<br>Same as above with O rings and decked head, you can probably get 70-80psi on occasions without problems.<br>You will just have to replace or retorque your bolts on an annual basis.<br><br>When you lower your compression a bit say with a Marine gasket then your chances for squeezing a gasket out are less.<br><br>If you plan on boosting over 40psi on a regular basis, let the engine water temp come up to operating temp and let your oil pressure get down to its normal warm point before boosting high.<br>Also, retorque your head bolts (they do stretch after they leave the factory and are ran for a while).<br><br>--Justin

BigBlue

You should be able to hold 50-60 PSI on the stock gasket alone. Just as long as they are correctly torqued. I would think with studs and o-ring, you could take bout 80 psi. Lower the compression a little (80 psi on 16.5 or so compression is a LITTLE high ), and I'd think you could hold over 80 psi. What do the sled pullers run? I've heard something like 120psi and 3 turbos or something? What kind of compression do they run?

thumper 549

I do know this that it is cheap insurance to replace the bolts.
Infact any bolts shold be replaced in a critical zone[ not reused].
thats my opinon.

Battering Ram

With the correct headgasket and stud setup... pullers are keeping things sealed over 150psi.

BigBlue

With what type of compression? Stock 16.5:1 (or whatever it is) or lower? Like 15:1?

cabrokr

Depends on the size wire used for the o-ring, the crush, and the type of gasket used.
Also will depend on the position of the wire. Not everyone is setting them up the same.
Drive pressures can play an important factor in blowing the gasket too, along with some other variables.
I have not heard of anyone able to run boost of 150psi+ because the bottom part of the 5.9 will not sustain it even if the head will.

Battering Ram

[quote author=cabrokr link=board=7;threadid=17542;start=0#msg166237 date=1059635577]
I have not heard of anyone able to run boost of 150psi+ because the bottom part of the 5.9 will not sustain it even if the head will.
[/quote]

There are several out there... one truck is making 190psi with just twins... and the bottem end is still there.