the compression numbers are 175 cyl 1, 90 cyl 2, 50 cyl3, 40 cyl4 based on these I would surmise I may have a blown head gasket between 3 and 4 however the difference between 1 and 2 is more than 10 percent which in my experience is the allowable tolerance. I am considering doing an in frame overhaul. or replace the engine. kinda depends on which i find to be cheaper. I dont need a new engine for as little as I will use the lift but I would like ti to be in half way decent shape.

now is this mazda engine an "industrial" engine or an automotive engine adapted for industrial use. can I go to the local parts store and get engine components? and what size is the engine? does this engine have removable cylinder sleeves? anything else I need to know before considering overhauling the engine vs replacement? thanks for the help guys.