2tg head gasket size question

[Noof]

Hi All,
Need an answer to a probably silly question.
If I have a set of 86 mm pistons and a block bored appropriately. Can I use a standard head gasket for this build?
It looks like it suits but would like to make sure?
Pretty sure that the block I got the pistons from when built had a standard head gasket so someone has obviously thought it ok in the past?
Any comments from the experienced 2tg builders?
Thanks
Nathan

[BrianGT]

If it was me I would use a std gskt. Once you go past a 1mm oversize you run in to problems.

I did use a std gskt on a 89mm bore but it only lasted about 2,000 miles.
I did it to get home and whilst I was waiting for one made......I now have a 90mm gskt on a 89mm bore.

[BrianGT]

If it was me I would use a std gskt. Once you go past a 1mm oversize you run in to problems.

I did use a std gskt on a 89mm bore but it only lasted about 2,000 miles.
I did it to get home and whilst I was waiting for one made......I now have a 90mm gskt on a 89mm bore.

[71TA22]

Standard head gasket should be fine for an 86mm bore.

All the standard head gaskets I have measured have a 87mm holes in them.

[J-M kujala]

Yeap like Mike says, up to 86mm with no worry, just install it. And diam of rings at HG are 87++mm

With 86- 87mm pistons had to check that headgasket properly match to a block. I have put small drops super glue to the gasket corners to keep it in a place. Sometimes those pins in a block had some clearance between gasket, so they do not always hold the HG in a correct place with 87mm bore.

I have always use stock HG in N/A engine (87bore) without problem, but seen that they do not always match properly to the block

[BrianGT]

The reason that I had a problem using a std gskt in my 89mm block was that the lip of the gskt just overlapped the bore .....the piston top was level with the block and the piston domes were recessed from the edge....but the heat of combustion melted the metal lip of the sealing ring and it split.
I knew it would do it but I needed to travel 350 miles home and it made it...luckily.
Not to be recommended.
I think 87mm would be the maximum you could get away with.

[Noof]

Thanks again everyone,
I have read that you use a little sealant around the water housings.
Do you guys do this too? What sealant is recommended for NA build?
Thanks
Nathan

[J-M kujala]

I have Never use sealant to water passages, only a littlebit where is timing cover joint to the block.

[BrianGT]

Agree with Kujala........only where the gasket sits over the timing cover. I use Hilomar.

[Noof]

Thanks again everyone,