O-ringing the block

[Gav]

OK

Rebuild is about to start on the RB26.

Most engine builders that I have spoken to recommend copper O-ringing of the block in combination with the standard Nissan head gasket. One shop recommends against this, however, and to simply use a metal head gasket.

I expect to be running in the region of 1.5 to 2 bar of boost.

Comments and experiences?

[Simonster]

I have Copper o-rings in my RB25. Will run 1.5 bar

The guy that built my engine has been building Nissan and Toyota racing engines for about 30 years. He does this religiously on his turbo cars, in fact he has run 35psi on one of his race engines without failures.

I guess you'll get answers that vary depending on what people have experience with. Metal or copper have the same purpose, provide a stronger headgasket thaht won't fail under higher boost.

It would be interesting to hear Sydnekid's response?

OK

Rebuild is about to start on the RB26.

Most engine builders that I have spoken to recommend copper O-ringing of the block in combination with the standard Nissan head gasket.  One shop recommends against this, however,  and to simply use a metal head gasket.

I expect to be running in the region of 1.5 to 2 bar of boost.

Comments and experiences?

[Bl4cK32]

I just had my rb31det built. Its running a 3 layer full metal head gasket. I was advised against using o-rings because, for example, what if u score the block so it requires remachining? U need to pay to get it re done.

No full metal head gaskets dont cost an arm and a leg. The one i used was a brand called "Cometic" It cost like SFA i think less than 300? Comes from the US. My engine builder said guys use it regularly in Group A, or diesel engines, cos it holds sh*t loads of boost

[Gav]

One for; one against

Comments from others?

[benjiman74]

Heres another one for the against.

I haven't heard of an rb26 having a head gasket failure. From what I understand the pistons will usually fail before the head gasket lets go in an rb26. A mate of mine whos just built a tough FJ sought advice from Ray Hall regarding o-ringing and was strongly advised against it. His suggestion was ensure both the head and block are true and use the original nissan head gasket and you wont have a problem. He is running a gt35 @ 2 bar.

hope this helps to your decision making.

[dangerous_daveo]

Not wanting to start another thread... But two things. Why not use O-Rings? I mean for the slight extra for the extra safty? Or do they have bad effects? Which brings me to my next question? Why do ppl 'O-Ring the block' ?

[Gav]

Not wanting to start another thread...  But two things.  Why not use O-Rings?  I mean for the slight extra for the extra safty?  Or do they have bad effects?  Which brings me to my next question?  Why do ppl 'O-Ring the block' ?

Nope - it's not another thread - these are the questions that I'm posing.

The cost is minimal and can't see any downsides. That said, I've been around high boost Nissans for quite a few years now and blown head gaskets (on std blocks) are a lot less common than ring lands letting go.

[Clint32]

i was advised against it, i cant rememeber the exact rason but i think if you need to remove the head you need a new head gasket whereas the metal stopper types are able to be reused, ill try and confirm

[Craved]

Is o'ringing the block some thing you do with thicker head gaskets? say the 1.6mm metal gaskets? thinking of using that gasket to decompress the engine for higher boost.

[Fitzpatrick Speed Works]

heres a question to ask yourself.

would i rather my headgasket blow or would i rather my piston or ring lands or rings or all of these blow under big boost???

head gasket looks like the cheaper option to me!!!

that is all

[Sydneykid]

Hi guys, ooooo goody a thread with a bit of controversy....

^ We always o'ring the block

^ We have NEVER blown a head gasket on an engine with an o'ringed block

^ The standard Nissan (via 'Olden) head gasket is very cheap ($25) and works perfectly with an o'ringed block

^ So who cares if I have to buy a new one when I pull the head off

^ We always use stainless steel wire, as copper wire compresses (flattens) and needs to be replaced

^ Damaged ring lands and blown head gaskets are mostly not caused by the same thing

^ Damaged ring lands are almost entirely due to poor tuning

^ Blown headgaskets have large number of causes, but not many are poor tuning

^ We never, ever use thick head gaskets. I prefer to fix the source of the problem, not stick a band aid on it.

So, for ben, we have an RB26 in the machine shop at the moment with a blown head gasket. No, it's not one of our engines. Now you have heard of one.

For the drifter, you would much rather have a weak link in your engine (sus head sealing) than tune it properly? Seems strange logic to me.

Shoot black, if I score the block, a few miserable $ to have the or'rings replaced is peanuts compared to what reboring the 6 cylinders and buying oversized pistons is going to cost.

As for clint, well I could buy 10 standard head gaskets for the cost of one aftermarket head gasket. If I have blown 10 headgaskets, then I have much more to worry about than buying #11.

Hope that was "interesting" simonster.

[Dump_Pipe]

This wanders a little from whats being discussed but:

I have an RB25/30 combo, instead of o'ringing the builder installed brass sealing rings which invovles removing fire ring from the gasket. I have never had the opportunity to run it with boost(and never will-another story), but was wondering whether anybody has heard of any others cars with this and it's reliability, he swears by it as he uses it in his race engines apparently.

[Fitzpatrick Speed Works]

thats not wat i meant sydney id be the biggest prick in the world to suggest have a weak link incase your tuning is out...i think you realise i didnt mean this... in cases i have had experience with, which i admit is only limited to 3-4 cases, we have recomended against o ring due to previous cases where massive boost pressures have resulted in a fried pistons, when in some cases the pressure might have only caused a blown head gasket...

these cases are isolated but are due to over zealous owners thinking that because of o-ringin their engine is in destructable to boost pressure the happy side of 2 bar, not the case and to the leahman, boost increases dont always equate to tuning refinement... many a time i have heard " i thought being efi the computer would know about it" i mean its only an extra 10psi i plugged in there without its knowledge...

as u eluded to a properly tuned engine wont blow headgaskets, so why waste on o ringin?

PERSONALLY i wouldnt bother, but if your happy then go for it...

[Sydneykid]

Sorry drifter, perhaps I was a bit over the top with the "weak link" allusion. But I see far too many RB's with blown headgaskets from causes other than excessive boost. So I would always o'ring the block whether or not boost was involved at all ie; we o'ring N/A engines as well. For all the reasons that we do them, we do RB's. Just because it's a turbo engine doesn't mean its immune to the laws of thermal dynamics and not limited by its metallurgy eg; RB's have a long cast iron block and an long alloy cylinder head.

We don't o'ring blocks because it makes me "happy", we do it because it is a demonstrably more effective method and it is cheaper than buying "brand name" head gaskets.

The reason the Japanese use "engineered" head gaskets is because they have a "bolt on culture", brought on by the fact that good mechanics charge like brain surgeons and good machine shops like movie stars. Thus they avoid removing the engine from the car whenever possible. To compensate, they have engineered a whole host of parts that quickly bolt on and replace the high cost of labour with the lower cost of parts. Thick head gaskets to lower compression are a prime example of this culture, its a band aid but it's cheaper than the labour to fix it properly.

In Australia, and in the US, we don't have this situation because mechanics charge reasonable rates (in comparison) and machine shops are far more common and thus price competitive. We can do the labour, use less "engineered" parts and achieve a better result for less total cost.

So, I don't think it is always a good idea to slavishly follow a Japanese trend without understanding whether or not it's reason for being is in fact transferable to Australia.

[sprint32]

Here, Here.

As a matter of fact there's a bit of a trend I hear of sending engines over here to be worked on cause it's cheaper to ship it over, have it worked over, and then ship it back. Good post sydney kid. Break the trends. (methods I mean, NOT the yen coming to australia! Encourage that! he, he.)

[KamikazeR33]

guys i think i have a fair understanding of what is done in 'O' ringing the block, but just to make sure and for the newbies out where who dont know :

what is done to 'O' ring the block

how much does it cost? (average)

[Fitzpatrick Speed Works]

totally valid point with the fact that cast to aluminiuim is always a factor in thermal dynamic loading...im just basing my reasoning on peoples misconceptions of what o ringin achieves... it does not result in a bullet proof engine is my point, o ringin doesnt make your engine indestructable!!! i know this is not what you are getting at sydney, i just want to make others realise this...as i have seen first hand people who think it does.. i also strongly recommend against machined oversized metal head gasket that are offered by japanese tuning companies, they are simply not worth the money, and depending on budgetry constraints o ringin is a luxury for me rather than a nessesity(spelling).

However id be more open to sydneys advice, i just wanted to make you aware your engine is not boost proof just due to the way the head is sealed..

[Bl4cK32]

i also strongly recommend against machined oversized metal head gasket that are offered by japanese tuning companies, they are simply not worth the money

I bought my Cometic 3 layer full metal head gasket (which i was told the Group A boys use, and their also used in diesel engines) - which does the same job as the Jap brand ones.

It cost less than $200.

[Sydneykid]

Hi guys, this is a fairly educated forum so I doubt that many people reading would think o'ringing is a panacea for all things breakable in an RB engine. There is plenty of discussion about forged pistons, conrods, rods bolts and good tuning being important if you want to push the envelope on your engine.

To answer the kamikaze ones questions;

While the block is on the borer and/or honer we machine a small circular groove on the deck of the block around the bore. Into the groove we fit a piece of stainless steel wire (held in with Loctite) such that 50% diameter of the wire is embedded into the block and 50% protrudes. When the head is bolted onto the block the protruding wire presses into the head gasket and prevents it from moving and makes a tight ring seal on the head.

You can o'ring the head instead of the block, we only do this when we are not removing the block from the car. You can also o'ring both the head and the block, however the machined rings are not the same diameter, they are concentric. This creates a double seal into the head, this technique is known as "double o'ringing" or commonly "W ringing".

As for cost, well we charge $15 to $20 per cylinder if done on the boring and/or honing machine at the same time as the block is being bored and honed. The set up time is thus spread over the 3 operations. Obviously it would cost more if it were done separately.

Hope that answers the questions

[KamikazeR33]

cheers SK

always one to come up with the answers

u should write a book