So I have this Sachs 505C engine and its' piston is a bit beat up but the bore is salvageable. The difference between it's current piston (which I assume is original) and an A or B piston seems to be it is about 3MM shorter on the bottom intake side. The transfer openings are slightly larger as well. Wrist pin positions are the same from the top.
The question is, can I use an A/B piston of the appropriate diameter and would some trimming to match the original even matter? The current piston measures 50MM on the exhaust side and 47MM on the intake. A and B measure 50MM on both sides.
I had run this jug and piston already on a 504. It ran well but couldn't get much past 33mph using the A piston and new rings. 120PSI compression.
At BDC the piston peaks above the lowest part of the exhaust port by about 2-3MM Is this normal on a C engine and would there be gains if I trimmed the top of the piston a bit?
I gave up and went the Airsal route on the 504 but would like to see what I can get out of this properly running C on a Balboa with just a 15MM carb and pipe.