O-ringed block?

[Eclipsekustomizer]

Back again guys thanks for all the help with the head gasket. Now i see guys talking about an Oringed head or block. What exactly is this. I have never heard of doing this. I am assuming its a mod but have no idea. Please enlighten me o great dsmers. Thanks a ton. This is the best dsm sight i have found and dont even bother going back to the other ones!

 

[ed1380]

O-ringed blocks are used in the 600+hp range

 

[VTEC_THIS]

O-ringing an engine block or head is usually used when someone is planning on running high boost and/or nitrous since it acts as an aid in helping to seal the headgasket. From what I've seen, this is more directly related to pressure than horsepower. To o-ring a block or head, a machinist will cut a groove into the metal around the cylinders and will put wire into the groove. Depending on which headgasket is planning on being used (and personal preference), the method could vary slightly. Copper or steel wire is typically used. I would personally recommend steel wire though since the copper wire could crush when torquing down the head.

For example, a lot of people have had success using a composite HG (whether OEM or FelPro) with ARP head studs and it holding 30PSI. With the added o-ring and L19 head studs with this setup it should be capable of holding 30-40PSI. 99gst_racer is a perfect example of this - he's currently running a compound turbo setup with 40+PSI on this setup!

We will be running a similar setup shortly (minus the compound turbo setup). We should actually be getting our engine block back from our machinist in the next couple of days and can post some more pictures of the o-ringed block. The pictures below are just examples. With a composite headgasket, the o-ring would press into the metal rings on the headgasket.

If using a copper headgasket, the block would be o-ringed and the head would have a receiving groove cut into it since the metal o-ring on the block would push the copper headgasket upwards. From what I've read though, copper headgaskets are better suited for race only applications since people have had issues with them sealing long-term.

If planning on using a MLS headgasket, I wouldn't recommend o-ringing the block or head since MLS HGs aren't supposed to seal very well when o-ringed.

I think in our applications if you're considering getting the engine o-ringed, it would be best to have the block o-ringed. My reasoning for this is because the block is cast iron and is much less likely to need to be re-surfaced/decked over time. The cylinder head on the other hand is aluminum and is more likely to warp and need to be milled over time than the block.

The cost of o-ringing is pretty reasonable as well. We're paying $80-100 to have our block o-ringed. You might not be able to find it that cheap but it really shouldn't cost more than $200 if you call a few places and get some quotes. IMO, it's cheap insurance for high boost applications.

If using a composite HG with o-ring you get the best of both worlds - high boost without worrying about blowing a HG and not having to worry about the sealing issues of a MLS.

 

[Eclipsekustomizer]

Thank you that was an awesome explanation and the pictures helped alot. I am only shooting for around 20-25psi so i dont think i need that just yet. Again awsome info man. Well done sir.