Ok, I am sure at one point or another we have all come across a head gasket issue. Something I have discovered is that every time I have had a gasket failure the gasket was the same size as the bore. Most recently I have switched to a gasket that is slighty bigger than the bore and have had zero problems at all. Is this just a coincidence?

What do you all feel works best for sealing a head gasket on a large bore motor, 85mm-87mm on a B Series motor or 89mm on an H22. I just want to here others experiences, thoughts on this subject.

Cliff Notes:

When I use 86mm bore-86mm HG I get problems
86mm bore- 86.5mm HG No Problems

 

sounds intresting... why would this be? anyone can shine a light to this?

 

Headgasket failure in most cases happen when the head studs aren't torqued to spec. When the head isn't resurfaced correctly, or even the block isn't decked as well...I've also seen aftermarket headgaskets fail to seal up because of a manufactures defect...

I recommend using only OEM gaskets on Honda motors...if you went big bore, just have the OEM gasket bored to your spec...

 

My gasket is just fine right now and it is a cometic. This is not the debate I am trying to have. I want to know about what makes, if at all, an gasket that is larger than the bore more resistant to failure.

Both my block and head were machined. They are as flat as they come. The issue comes from the limited amount of material trying to seal.

 

IMO...Its just coincidence...

 

Sometimes if the gasket hangs into the bore a little, it has the ability to get really hot in the over hang area. Sometimes this can cause a problem, sometimes it won't. It all deopends on the BTU's of the combution really, and the timing. I NEVER have any part of any gasket hang into the combustion chamber, if not for anything else than peace of mind.

And to let you know, I never have gasket issues with the motor I build.

 

So it is not a coincidence then. :-) Thanks. I will stick with ordering my gaskets a little larger than the bore.