SoCalPlaneDoc
New member
not *exactly* a Bellanca topic but it's from an 0-470 so since the -2's have them...
Wrist pin I pulled from #1:
the back story:
1700 hr engine (ya, it's over TBO, don't go there, it's OK). Otherwise healthy - 2 months ago owner noticed unusual oil on belly - I checked compression - #1 way low. Pulled it, replaced with chrome exchange unit - told owner how to break in.
12 hours later, post break-in oil change - still has oil on belly. compression on new cylinder is 30. Pulled it, looked glazed. Gave owner severe finger wagging and sent cylinder off to shop. They "refreshed" it (hone, new rings, inspect, etc) Reinstalled, reminded him how to break in.
13 hours later, post oil change, Compression 10!
Bore scope showed severe scoring. Pulled it and found wrist pin like you see in the pic.
The pin is not worn from rubbing on the cyl wall, it's been "hammering" on it. You can see how the jacket on the tapered aluminum end has been peeled back. the pin fits the piston perfectly. the piston was the same one used before. The conn is the original one, the hole for the pin *might* be a little loose.
I cant imagine what could cause a pin to repeated hammer on the cylinder wall. It drew mass attention from all the airport mechs who heard about it and came to see - none had ever seen anything like it.
The plane is a 4-owner partnership, 2 of the owners are a married couple, wife is Type A, pants wearing non-pilot with a huge checkbook. All of them use the plane exclusively to fly to Mexico for windsurfing.
The pants made a unilateral decision to replace with a factory new engine, husband didn't dare speak up. I'm going to confiscate his man card. :lol:
Wrist pin I pulled from #1:
the back story:
1700 hr engine (ya, it's over TBO, don't go there, it's OK). Otherwise healthy - 2 months ago owner noticed unusual oil on belly - I checked compression - #1 way low. Pulled it, replaced with chrome exchange unit - told owner how to break in.
12 hours later, post break-in oil change - still has oil on belly. compression on new cylinder is 30. Pulled it, looked glazed. Gave owner severe finger wagging and sent cylinder off to shop. They "refreshed" it (hone, new rings, inspect, etc) Reinstalled, reminded him how to break in.
13 hours later, post oil change, Compression 10!
Bore scope showed severe scoring. Pulled it and found wrist pin like you see in the pic.
The pin is not worn from rubbing on the cyl wall, it's been "hammering" on it. You can see how the jacket on the tapered aluminum end has been peeled back. the pin fits the piston perfectly. the piston was the same one used before. The conn is the original one, the hole for the pin *might* be a little loose.
I cant imagine what could cause a pin to repeated hammer on the cylinder wall. It drew mass attention from all the airport mechs who heard about it and came to see - none had ever seen anything like it.
The plane is a 4-owner partnership, 2 of the owners are a married couple, wife is Type A, pants wearing non-pilot with a huge checkbook. All of them use the plane exclusively to fly to Mexico for windsurfing.
The pants made a unilateral decision to replace with a factory new engine, husband didn't dare speak up. I'm going to confiscate his man card. :lol:
