KR-1S.co.uk Forum

Hi guys,

Noticed the other day that the holes in the standard head gasket for the bores are about 57.4mm in diameter and not 56mm. Why is this?

Surely it would be beneficial for the holes to be 56mm. That way all the combustion will be taking place directly above the piston and not adjacent to it. I know that it is a tiny volume of mixture i am talking about here but surely it all adds up.

Looking at making a copper head gasket with 56mm holes.

Dan

maccas wrote:
Looking at making a copper head gasket with 56mm holes.

Dan

Spare yourself that trouble, and go straight for O-ringed heads. it offers the same solution, but when you need a replacement it is much easier : just stick in new O-rings instead of having to make a new gasket

Hi Janbros,

I would go with O-rings but my head volumes are on the small side already so I need to keep as much volume as I can. Using o-rings would mean I would have to machine the combustion chamber deeper into the head to compensate for the lost volume which I don't really want to do.

I'm aiming for the deck height to be set at 0mm so that would mean I would have to machine the combustion bowl and squish band 0.8mm deeper at least to get the required squish. Then I would have to enlarge the bowl to get the required volume. By using a head gasket I can use an appropriate thickness of copper to get the required squish and then work the combustion bowls to get the required volume.

Dan