Headgasket - Grommet Type / Nismo / Nitto / etc

[The Mafia]

Hi All

I'm currently building another RB26 race engine. Trying to refine a few things while doing this. 

Ideally I want to run a square edge bore with a super thin headgasket (0.8mm) that is the same as the bore diameter (86.5mm). Unfortunately, there are lack of items in this size and combination.

I have decided to run a 87mm gasket but I absolutely want to run the grommet / fire ring style. Nitto has exactly this. Unfortunately Nitto only makes 88mm diameter and 1.2mm head gaskets. 

I am looking at the Nismo 0.9mm gasket, they have this in the 87mm variant. But, I cannot find any details about them at all. I have searched for part numbers, Nismo directly, etc and cannot get any information. 

Question 1 is, what style of sealing are Nismo headgaskets? Are they are grommet style? Does anyone here have a Nismo gasket on hand they can look at for me? 
https://www.rhdjapan.com/nismo-head-gasket-0-9mm-bnr32-bcnr33-bnr34-wgnc34.html

Question 2 is, is there anything that anyone can recommend that is 87mm, 1mm or below, and grommet style? 

Thanks

Edited July 8, 2021 by The Mafia

[R.3.2.G.T.R]

https://platinumracingproducts.com/collections/new-release/products/athena-sce-vulcan-cut-ring-head-gasket

[The Mafia]

They are unfortunately not below 1mm. 

[2pee]

Tried John Tripp? (07) 3285 7320. Not sure if he has sub 1mm, but he's made one-offs for us in the past as required.

[Ben C34]

Why do you desire such a thin gasket?

[The Mafia]

Trying to get the most optimal quench zone. Going to almost square bore edges and a super thin gasket with the best squish. This helps reduce detonation, increases combustion chamber efficiency, and also helps with strength.

It's not a huge gain but every little bit counts.

It's for my circuit race car. I've got 9.5:1 pistons, and will opt for a 0.8mm head gasket. should get be a nice 9.8:1 with a really good combustion chamber. 

Car is E85 only so won't be an issue with knock ceilings. 

[Dose Pipe Sutututu]

On 12/07/2021 at 8:34 AM, The Mafia said:

Trying to get the most optimal quench zone

Like what you're trying to do!

Yet there are still people in 2021 who grind out their cylinder heads to go backwards.

[The Mafia]

I agree. Bevelling the edges and having a thin gas layer in the quench zone, and 88mm gasket on a 86.5mm bore is not going to help things. These all aid detonation. This is why you see a lot of RB26s with detonation on the quench pads. 

Getting that mixture to the center of the chamber is important. A thin gasket that is the same diamater as the bore or as close as possible (0.5mm bigger max) is the best way to do it. 

The only time you really need to remove the quench area and increase the chamber size is if you are running 50-60-70-80-90psi of boost. 

Static comp with 90psi is quite high so you need to generally lower the compression overall. 

[Dose Pipe Sutututu]

I've always put Tomei gaskets into cars I've helped build and in my own

They use the same grommet style characteristic as the Nitto one, here's a 87mm @ 1.0mm variant.

https://frsport.com/products/tomei-1321870103-headgasket-87mm-bore-1-0-mm-thickness-rb26dett

 

Edit: Realised it out of stock and discontinued in the 1mm variant, however you could try channels like Jesse Streeter, etc. to see if they can locate one for you.