I ran a compression test last nite in my JDM gsr swap.

We got 175 -185 in cylinders #1,2,4 and in #3 we got 120

And when we looked inside the spark plug hole, it was caked with dirt and crap all the way up to the top of the head where the valve cover sits. We knew something was wrong just by looking into this cylinder. All the other spark plug holes were a lot cleaner and not even close to being that dirty. We thought it could be a blown head gasket ? Or probably a shot ring.....

Any ideas on what this could be from these symptoms ?

Also, will a mugen thin head gasket help produce anymore power in a jdm b18c gsr motor?

 

Sounds like it's time to leakdown test your motor... See what i posted in this and it may help https://honda-tech.com/zerothread?id=366743 Good Luck... Lemme kno if you need anything else... Latez