Is there a general rule as to how much Boost or HP you can run before you are suggested to oring the deck? I would guess that it would vary from motor to motor (mfg & BB or SB), but lets say a SBC, w/ATI blower.

also does the material of the head figure into it? ie, Aluminum more/less likely to lift?

thanks.
BW

------------------
Bob Wooten
r71chevy@earthlink.net
www.r71camaro.homestead.com

 

aluminum heads would be more likely to blow head gaskets because iron (the block) and aluminum (the heads) expand and contract at different temperatures.

you really dont have to o-ring the block unless you plan on big boost or you build the motor more as a race motor, ie high compression high boost.

 

O-ringing is a matter of preference. Many higher boost folks do not o-ring, since it is naturally the weak link and the head gasket will blow before the piston+rods do

The chevy smallblock has a decent head bolting design, so its not unusual to see 15 psi boost on their built motors with standard gaskets. I would personally consider it if you plan on going over 20 psi.

Andris, who will be o-ringing

 

I agree with the others here. You usually see the 5.0 crowd O-Ringing their blocks much more due to the bolt pattern on those motors allow the head to lift under some boost. The 350 bolt patterns are very strong, and you can run some good boost through them.

I like Skultes thing about the head gasket popping first and saving pistons ect.. LOL Its like a blow off valve
I had heavy detnation one time under full boost, and blew a head gasket on one side, and cracked 4 pistons on the other side.. The side the gasket blew had no internal damage..The side that held....well it was a mess.
One thing you can do that wil help without going through the hassle of O-ringing is to stud the block, with an ARP kit, which does a great job on blown cars I have seen with up to 16 PSI of boost.

 

Thanks gents!

I never thought of it as a fuse. I completely see the advantage to not oringing.

I am guessing here, but I would think that the advantage of Aluminum in the sense that it is less likely to detonote that Iron FAR outweighs the different expansion rate issue?

I always stud. personally the insurance of forged pistons, studed motor (rods, mains & heads) & felpro gaskets are automatics, & far outwiegh the small additional cost. the difference is probably MOSTLY in my head but the small actual difference is worth the sense of security that they provide.

tanx again
BW


------------------
Bob Wooten
r71chevy@earthlink.net
www.r71camaro.homestead.com

 

boy, sure wish that either there was a spell checker or i learned to spell.

BW

------------------
Bob Wooten
r71chevy@earthlink.net
www.r71camaro.homestead.com

 

yes, an aluminum head helps defeat detonation because of its ability to repel heat better.