To O-ring Or Not To O-ring?

[grippy]

I am throwing up if I should O-ring my RB cylinder block after the rebore is done? I have heard many arguments for and against.

Please post your opinions here.

I wish to run 25-30psi through the motor when completed.

Head gasket has not yet been decided as this swings with the decision on o-ringing the block. Considering a Cometic triple layer 1.2mm.

All opinions appreciated.

Rgds,

Grippy

[dazmo]

Absoloutly no need to Oring your block mate this is a very "old school" modification and was a common modifcation before more modern advancements in gasket material and design. There are plenty of RB engines out there running the sort of target boost that you are aiming for with a good gasket and not having any issue. I would consider this mod to be fairly outdated and totally uneccessary. I personally have not used the cometic gaskets before so can not give you an opinion on them . I usually use tomei gaskets in the majority of engines that i build and have never had an issue with them.

[Alf]

I use a Tomei MLS heaggasket no probs at 25 psi.

No need to o'ring motors these days.

Edited November 3, 2009 by Alf

[jdmser]

If you go with the Cometic the head and block both have to be completely smooth or it will leak.

[discopotato03]

I don't agree and don't think it's outdated .

I used to use Nismo competition head gaskets in Nissan L Series and FJ20 engines and never had problems with them . They basically had the wire ring inside the gaskets fire ring and you could plainly see the impression they left on the heads face .

As far as I'm concerned Nissan Japan's OEM head gaskets are good things and if you use a wire ring to form a mechanical lock on the outside of the fire rings sandwich they can stand higher cylinder pressures without creeping and breaking their seal .

Your calls , OEM standard of gasket with wire rings or very expensive gaskets without .

There is actually another alternative and that was one I saw Alex (of Pulse Turbocherging/Pulse Racing) years ago use with his FJ's running 30 pounds of boost . Essentially you cut the fire rings out of a std headgasket so all it does is seal oil and water in their passages . The block has a step machined right at the tops of the bores and a non ferrous shallow ring is used to seal the chambers to the block face . I don't remember exactly which material these flat faced squared off rings were made of but the resulting mechanical seal helped him crank 700 + horsepower from his FJ Turbo engine on an engine dyno .

Not bad from an admittedly solid two litre four .

A .

[grippy]

Thanks for the input,

I feel that O-ringing my block is possibly not going to give me any advantage. The engine is going to be used 90% of the time for track/ supersprint work although it will remain registered.

I have a good friend that owns a motorsport shop that mainly deals with drag cars and every engine I see there is O-ringed. So I cannot get an objective opinion from him. He believes that all high boosted engines should be o-ringed but I tend to disagree.

I have another friend that was recommended to O-ring his SR20, he did so, then 6 months later has the block filled to remove the o-ring cutout after advice from a different tuner.??? What is going on there??

The problem that I have with it is that once it is done the block is never the same. I think I will build this motor without the O-ring machining, run either a cometic or Tomei metal gasket, run the boost that I need and go from there. If I find that I start bowing out metal head gaskets maybe I will consider modifying the block further but I would like to keep my block in original condition till then.

Thanks for opinions, I would like to look into this further before a final decision is made. I am still leaning towards no o-rings.

Rgds,

Grippy

[discopotato03]

The problem you'll have is that everyone is going to have slightly different opinions so you have to find someone you trust and do the grasshopper thing with them .

What you need is facts based on actual results rather than what someones personal spin is on these things .

The bottom line (IMO) is that for significantly higher cylinder pressures you either use a competition standard of gasket or find ways to make more OEM ones stay put around the fire rings .

Your call . How about we ask engine builders about their experiences with WIRE rings .