Wich Apexi HG Od. For 86.5 Bore ???

[Master Chief]

Hi all.

I have a 86.5 Bore in my block, and i want to get a new Apexi HG.I am going for the 1.1mm, but was wondering about the bore OD to get.

Apexi have a 88mm Bore hg, designated for a 87mm cylinder,or a 87mm Bore hg, designated for a 86mm cylinder.

Now since i have a 86.5mm cylinder bore, i was wondering what would be better to get.

I am worried that with te 87mm HG, the fitting would be to tight with the bore, and might slightly penetrate into the cylinder - meaby causing premature failure, or burn due to exposure to the burning gases....

The 88mm on the other hand, leaves a big area between the head and the block, like a small cut, that could meaby, be a high heat potential area, and cause detonation or worse.....Allso, this leaves a very small HG material between the Cylinders (1 mm less than with the 87mm), wich could meaby leak coolant into the cylinder ????

Could be that i am exagerating about this, so guys, what to go for ?

Thanks.

[HighPsiS13]

I ran a 87 on my 86x86 block with zero problems and dont see any reason why the .5 would have an issue.

Spend the money on that apexi headgasket those things are so so so so so awesome .. a little copper spray and lots of dyno runs on all my cars has made me a true fan of them.

The Apexi and Tomei HG's are the business!

[Master Chief]

The thing with 86 bore and 87 hg, is that you have about 0.5 mm on each side, while with 86.5 , you only get 0.25mm on each side.

Taking the fact that a HG is not sitting on the head 100% fixed, during install it would be harder to line the bores in the HG with the cylinder, because it only takes a really small movment of the hg , to cause the hg to penetrate the cylinder area, and expose the gasket to the burning gasses....

That my concern with th 87.

With a bigger HG, you wouldnt have this problem, but the potential of CREVICE ERROSION is greater....