230psi in a Poulan (42cc, wild thing, etc)!

[777funk]

I accidentally free ported my first cylinder with this thing. Bought a new cylinder and this time I went a little too far and reduced squish to almost zero. I can still squish solder, barely (very hard to turn past TDC). I took a little off of the outer edge of the piston top, just incase.

But what I was surprised to see is that I ended up with 230 psi of compression. The ring gap was bigger than I hoped for (about 0.020"), but that didn't seem to matter much. I suppose the pin bridges much of that. Is there such a thing as too high on compression?

 

[David Young]

what saw was this. did you test compression after you ran it? did it run ok what is the exhaust port at?

 

[dangerousatom]

Id be a little worried about the piston thermally expanding vertically ( 2-3 thousandths ) while the combustion chamber ceiling lowers once heated up. If your near zero clearance now somethings going to give once she hot.

Maybe recheck your squish with a full wrap of solider around the piston top ( hold it in place with a light brush of super glue ) and if the wife lets you toss the saw in the oven at like 200 for 15min before rotating w/most plastics removed. Otherwise Id heat up the jug till its good n hot.

If your running no gasket your all good IMO just find w/e is +10k thick and use it as a gasket.