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i cracked open my new-to-me O-320 this evening. its a 57 model -- narrow deck with no banana plates. Lyc says it was delivered to piper
in 57. I believe it was the original engine on my 57 PA-20/22. This engine -- i was told -- was supposedly overhauled about 15 years +- ago.
I first bore scoped it. I have 3 cylinders that show new looking cross hatch. but #1 cylinder has no cross hatch like the other 3--- but its very smooth looking like it never got honed to make the pattern. All 4 cylinders are operating room clean. New rings - new pistons--- none of it ever run. engine never had oil put in it. I put pickleing oil in it when I first got it.
Everything looked oK that I could see by scope. So I have pulled #1 cylinder just to look at the cam and generally inside. The camshaft looks either new or ground. i can only see a little line on the lobes where I have rotated it a few turns in the pickleing oil. All inside the case is equally spotless. Not even any stain.
All I can see is maybe some dried up gummy perelketone at the edges of the case where the cylinder slides in.
Frankly --- I cant see how it could get better than this ! My only mystery is why #1 has no cross hatch. The outside of #1 matched perfectly with the other cylinders. New STD. pistons and new rings. My plan is to measure the bore on #1 and see if it is round and what the taper is-- if any. Then see if that falls into new specs. dont know if I should remove the valves. Sometimes there is leftover grinding grit on the stems if the guy was sloppy. I guess if I take the springs off I can feel of the stem-guide clearance. (just to double check---) and look at the seats and grind.
This engine was bought with the airframe- and I considered it a core--- because you never know what people say and it was 2 or 3 owners ago.
But I am pretty excited.
The big question for later on-- is do I split it just to change out the oil seals in case they have dried out ? I have a while to think about that as I am building the fuselage now. and only part way through the wings. I have not yet gotten to the AD list yet.
The bottom of cylinder 1 has some electro penciled writing -- including "PMA" --- and since they pistons say STD-- that makes me think these are new jugs. Maybe if there is a serial number - i might trace who did the overhaul. ( no logbooks for it) i ---- THINK-- i may have the owners name and number who owned it when it was done. I may try to call him tomorrow. He could have gone through a dozen cell phones since then though...... :-)
Any thoughts ?
Tim
in 57. I believe it was the original engine on my 57 PA-20/22. This engine -- i was told -- was supposedly overhauled about 15 years +- ago.
I first bore scoped it. I have 3 cylinders that show new looking cross hatch. but #1 cylinder has no cross hatch like the other 3--- but its very smooth looking like it never got honed to make the pattern. All 4 cylinders are operating room clean. New rings - new pistons--- none of it ever run. engine never had oil put in it. I put pickleing oil in it when I first got it.
Everything looked oK that I could see by scope. So I have pulled #1 cylinder just to look at the cam and generally inside. The camshaft looks either new or ground. i can only see a little line on the lobes where I have rotated it a few turns in the pickleing oil. All inside the case is equally spotless. Not even any stain.
All I can see is maybe some dried up gummy perelketone at the edges of the case where the cylinder slides in.
Frankly --- I cant see how it could get better than this ! My only mystery is why #1 has no cross hatch. The outside of #1 matched perfectly with the other cylinders. New STD. pistons and new rings. My plan is to measure the bore on #1 and see if it is round and what the taper is-- if any. Then see if that falls into new specs. dont know if I should remove the valves. Sometimes there is leftover grinding grit on the stems if the guy was sloppy. I guess if I take the springs off I can feel of the stem-guide clearance. (just to double check---) and look at the seats and grind.
This engine was bought with the airframe- and I considered it a core--- because you never know what people say and it was 2 or 3 owners ago.
But I am pretty excited.
The big question for later on-- is do I split it just to change out the oil seals in case they have dried out ? I have a while to think about that as I am building the fuselage now. and only part way through the wings. I have not yet gotten to the AD list yet.
The bottom of cylinder 1 has some electro penciled writing -- including "PMA" --- and since they pistons say STD-- that makes me think these are new jugs. Maybe if there is a serial number - i might trace who did the overhaul. ( no logbooks for it) i ---- THINK-- i may have the owners name and number who owned it when it was done. I may try to call him tomorrow. He could have gone through a dozen cell phones since then though...... :-)
Any thoughts ?
Tim
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