cpr
Addicted to ArboristSite
AH-81 Update
Had time this am to pop the 81's jug. The weld repair was quite good on it, but there were other surprises inside.
Seems my decision to replace this jug was a good one, it was a ticking time-bomb. Sooner or later that piece was going to come loose and grenade the whole thing.
You can better see the piece I am refering to in this shot. The cracks continue between the transfers.
Cracked between transfers on the other side, too.
Seems there are more pistons and cylinders beyond the 90deg. change in exhaust port relative to thrust of piston...
The "old" piston is on the left, the "new" on the right. The corresponding transfer windows in the jug are also different. I port mapped the "old" jug and the exhaust and upper transfers are, for all intents and purposes, the same. The "old" lower numbers on the jug are .865 wide, 2.250 down to top and 3.140 down to bottom. On the piston, the "old" windows are .625 crown to top of port and .930 dia. While the old one's are significantly larger, I'm not porting out the "new" jug. This thing is quite thin and, apparently, brittle enough. I'll just be happy with it running rather than being a monster.
Lastly, the transfer ducts cannot be used as there is no place on the case to feed the charge to them.
Had time this am to pop the 81's jug. The weld repair was quite good on it, but there were other surprises inside.
Seems my decision to replace this jug was a good one, it was a ticking time-bomb. Sooner or later that piece was going to come loose and grenade the whole thing.
You can better see the piece I am refering to in this shot. The cracks continue between the transfers.
Cracked between transfers on the other side, too.
Seems there are more pistons and cylinders beyond the 90deg. change in exhaust port relative to thrust of piston...
The "old" piston is on the left, the "new" on the right. The corresponding transfer windows in the jug are also different. I port mapped the "old" jug and the exhaust and upper transfers are, for all intents and purposes, the same. The "old" lower numbers on the jug are .865 wide, 2.250 down to top and 3.140 down to bottom. On the piston, the "old" windows are .625 crown to top of port and .930 dia. While the old one's are significantly larger, I'm not porting out the "new" jug. This thing is quite thin and, apparently, brittle enough. I'll just be happy with it running rather than being a monster.
Lastly, the transfer ducts cannot be used as there is no place on the case to feed the charge to them.
