Originally Posted by crassius
I agree on recovering compression by lapping, except I hate to see the compression ring on the bottom of the head go away - same technique, but applied to top of cylinder instead.
That's how I set up my own engines by lapping the cylinder, more like cutting off about .040 " from the top of the cylinder on my lathe, then using a .016" thick copper gasket to set the squish clearance down below 0.5mm. I also use copper base gaskets since they don't compress like the paper fiber ones do and there's no issues with stacking 3 or 4 of them if needed. On one engine 1 shaved .044" off the bottom of the jug and .040 " off the top so I could set the port hight as well as get my squish clearance where I wanted it. The real reason for shaving so much off the bottom tho was because it took that much cutting before the mating surface was flat and true. This one I made a .040" thick spacer out of aluminum and used a .016" thick copper gasket on both sides of the spacer, then I ended up cutting .052" off the top of the cylinder to get my compression and tight squish clearance back.... yeah I probably spent way too much time on that engine but I just got a new lathe and what a better way to test it out...
But that engine was a screamer when I was finally done with it...