Looking for info on headgasket

[EricYellow]

Can anyone tell me more about this headgasket?
Is it OEM, aftermarket, thickness etc...
It has 391 stamped on it and it has what looks like 2 notches in it on the side (left upper side in pic 2)
It's been modified to fit an O-ringed block.

 

[PobodY]

What do you mean by "an O-ringed block"? - Given that it has the Nissan logo stamped into it I'd suggest it's OEM... but if someone had modified it to make it fit, I'd suggest it wasn't meant for this engine (it's probably for a black-top SR20).

 

[stumo]

What do you mean by "an O-ringed block"? - Given that it has the Nissan logo stamped into it I'd suggest it's OEM... but if someone had modified it to make it fit, I'd suggest it wasn't meant for this engine (it's probably for a black-top SR20).

george, an O ringed block has groves cut round the bores and has (usually)steel rings fitted to seal the bores better.

It's possibly a std GTiR gasket, there was only one thickness of gasket which i can't remember (whereas on nissan diesels the notches denote thickness).


with only 44 posts i won't introduce any ball rubbing antics to this thread.....

 

[wrc]

Probably means the blocks been honed and then someone has just used what looks like a stock Nissan gasket, and ran more boost etc.

 

[stumo]

Probably means the blocks been honed and then someone has just used what looks like a stock Nissan gasket, and ran more boost etc.

the gasket has no fire rings, so it's been modified to run O rings.........

 

[EricYellow]

Here are some pics of the block/o-ring, there you can see what has been modified to make the gasket fit.

 

[Mr B]

One of the problems with O-ring setup is getting the rings right height for gasket or gasket right height for rings when rebuilding. If too thick not enough clamping load is applied to O-rings & if to thin not enough clamping load is applied to gasket & oil/water ways can leak easier. You will need to measure exposed height of O-rings & get a gasket to work with it, standard gasket is 1.4mm & 1.2<>1.3mm once fitted. You will probably need to stick with paper gasket as they will compress more, easier to cut out fire rings & cheaper if you need try a couple of sizes. Another option is reducing height if O-rings if no gaskets of suitable thickness are available ...

 

[Makaveli_se7en]

I thought O-ring blocks were mainly used with copper head gaskets or is that not the case?

 

[Mr B]

Don't have to be but copper gastet does not compress so easier to calculate height. O-ringing blocks can be more trouble than it is worth ....