hi guys, Roger don’t be fooled by the return oil volume it could indicate that the main bush is worn. Oil spews from around the circumference of the bush into the oil pump cavity then into the crankcase through an exit hole.
I personally would not use SAE 20 oil as the thinner the oil the more oil can escape from worn parts, i did an experiment some time ago to see the leakage from the main bush, it allows the bush to be bathed in oil which is a good thing but too much coming out would starve the rest of the engine,...just my personal opinion, cheers