Thread: School me on what this headgasket is saying...

replace the head gasket, get a ve metal head gasket, new head studs.

stratton.

didnt get metal, since i wasnt going to have the block resurfaced, but i did get mazworx studs and oem gasket.

Left side - how it looked when i took the head off
right side - how it looks after the roloc discs.

Love them things.

btw. what do the numbers stamped into the top by each cylinder mean?

That motor has definitely had some detonation. You can see the pitting on the top of the block close to the cylinder wall edge on the exhaust side. Which is where it normally happens. Also looks like there is some pitting on the exhaust side of the piston close to the cylinder wall on piston 3.

The numbers on the block are the cylinder wall grade number for the piston grade your supposed to use. Again nissan did things soo precise on the SR motors they put grades to everything even though they were only like .0001-.0003 difference in each grade. They had things very very precise. But they all fall under standard bore 86mm which if you buy pistons thats what you would use.

Anyways i hope the gasket seals alright with the pitting. I had one that did that to me and with a metal headgasket it sealed fine so hopefully yours does too.

It was probably before my tune last year. and/or when i was at the track last month and it kept getting HOT from getting air in the system.

If only the roloc disc im using would fit so i could get the top of the front cover... guess ill have to use emery cloth or something else...

Thanks for the input Ashton.

Also I would not use roloc discs on a head surface, too aggressive grit IMO. I just razor blade it, and then take 2000 grit sand paper and water and just wet sand the deck until it's smooth like the intake manifold surface on the head. With a metal gasket, the smoother the surface the better. Rolocs sanding discs still leak the head too rough and you might actually go too deep and create a dip somewhere on the surface. 2000 grit sand paper and an hour spent on getting it smooth is my way. But yes, there is detonation and the gasket was about to blow out for sure. My buddy had worse pitting than yours and his pistons started to melt, and his Apexi gasket wasn't even burnt and had left perfect seal rings. Don't go back to that tuner, or have him monitor knock better.

Im positive i only got detonation when It was overheating on the track and had an air pocket in the cooling system, and overheated.

and the roloc im using is 120 grit
But i have some emery cloth on the way too

3m yellow roloc is what should be used for aluminum. With a metal head gasket you should have been able to clean the surface with brake cleaner or gasket remover. With a stock gasket you should be good because it will conform to the surface.

Got the gasket and head on, mazworx studs in and torqued to 65 ft lbs.