Depends on your plans but L19's would be enough but if you think you want that extra security, o ring head

 

Sorry to bring an old thread back, but are there any other big hp guys with opinions on this? I am debating on whether to do this to my block or not. It is a big hp build running alot of boost (50psi+) with a big turbo. I didn't have sealing issues before running about the same boost. Thanks for any info.

Aaron

 

What fuel are you running 50+psi on? I was told by my engine builder that an o-ringed BLOCK is not necessary for what 99.99% of evo owners do. I'm running 45 psi on c16 and no o rings. Perhaps if you are running methanol and 60 psi, you may need to readdress the issue, but if that is the point you are at, I would recommend listening to your engine builder, who is hopefully VERY reputable, and not the forums.

 

I am on E85. Was using 114 race gas but got better results with ethanol, and its cheaper. I am the engine builder.

Aaron

 

Do these o-rings sit flush with the surface of the block? Wouldnt doing this not allow the block to be resurfaced or milled later on?

 

The o rings do not sit flush with the surrounding surface. Not sure if ethanol is capable of 60 psi...not 85% anyways, maybe 98%. Not to go off topic, but your going to need a very serious fuel system to handle that much ethanol at those boost levels. Have you built an engine before? Hopefully you know what your getting yourself into.

 

I think you all missed the question.

He asked if he should o-ring either the head or the block not IF he should o-ring it.

I'd do the block if its all out. I think when people do the head its because it's easier to remove to send away to machining.

 

Gotcha, yeah...I would only do the block. But I still say that you don't need to.

 

No they protrude above the block deck slightly, then crushed by the head when torqued. I am sure if you had to resurface the block deck, that you could just re-do the o-ring groove to how deep it needs to be at.

Aaron

 

I am sure E85 will handle it. We were actually a little over 50psi before but hit a restriction point with my head and intake manifold. If i need to use E98 then that is readily available to me as well. My fuel system will handle anything i throw it at, and yes, i have built "plenty" of engines.

Aaron

 

If they protrude wouldnt it make sense to add a recieving groove in the head for an o-ringed block? idk, maybe im over thinking this thing.hah.

 

They are designed to crush/cut and make a better seal...but yeah, I would want to have a receiving/female groove on the mating side as well.

 

On my old L28, which was an I6 cast iron block with aluminum head I opted to o-ring the block. You are less likely to have the block decked as you are the head so going the block route allows changes to the head without affecting the o-ring.

We used SS piano wire that was raised above the deck by ~0.010" and was cut to seat into the stock head gasket fire ring. I like the o-ring route because you can utilize a stock head gasket, which is often better for sealing oil & water passages.

 

L19s and torque the head to factory spec. I never had a lifted head at 45psi.