took a punt on a secondhand short motor a while ago as temporary solution to get the car back on the road, so figured as it's too cold to work in the garage now was as a good a time as ever to strip it down and have a proper look at it and see what state it's in.
crankshaft looks ok; journals are decent as is the tail. one small mark on the primary gear front bearing journal
on a less positive note, when releasing the bearing caps it was obvious the motor had a serious blow-by issue as the crankcase interior was heavily sooted up. this is what the pistons looked like when they came out
not looking too promising at this point, but having bought myself a dial bore gauge and measured the bores they look to be OK. they're not perfect, but there doesn't appear to be more than one thou oval or taper variation in any of them, which i wouldn't have thought would be the cause of the sooting up
next check was ring gaps - compression rings back in their bores and gaps measured at half inch increments down to the bottom
helpfully, the ring gaps tie in with the bore gauge measurements with fairly consistent gaps all the way down the bore. What was also consistent was that the ring gaps were all massive, ranging from 23 to 27 thou
i've got the pistons bagged up wrapped in blue roll soaked with carb cleaner at the moment - hopefully i can get them cleaned up over the weekend and have a good look at them before deciding on next steps...