I just bought a Pitts that has been sitting for the last 8 years. It was started about 18 months ago once I think.
I just pulled the lower plugs and did a compression check cold. 3 cylinders were high 70's, two were high 60's and one was dead. All the leaks were exhaust valve leaks. On the dead cylinder I took off the valve cover, with the air on the cylinder I tapped on the exhaust valve and the pressure came right up to 74+.
The oil was changed to new before I bought it. I put in a new battery. With the plugs removed I engaged the starter. The oil pressure came into the green after about 20 revolutions of the prop. I let the starter rest. I engaged the starter again and the oil pressure quickly rose to the green arc. The plane was buried in the back of the hangar so I didn't pull it out yet to start it.
I have had some of the old school guys tell me to put some Marvel Mystery Oil in the cylinders and let it soak before I run it. I am not sure what this would accomplish. Is this an old wives tale? I guess this is a penetrating oil that would theoretically loosen some stuff up. I am guessing there is no service instructions that deal with bringing back an old unpreserved engine back to life.
I shoved a cheepo home depot borescope camera into the cylinder holes. I couldn't really get a good view of what is going on inside the cylinders. There might have been some pitting but I am really not sure what I was looking for and the camera quality was very poor.
Any advice would be appreciated. I plan to pull a cylinder but it will likely get ferried home first.
I just pulled the lower plugs and did a compression check cold. 3 cylinders were high 70's, two were high 60's and one was dead. All the leaks were exhaust valve leaks. On the dead cylinder I took off the valve cover, with the air on the cylinder I tapped on the exhaust valve and the pressure came right up to 74+.
The oil was changed to new before I bought it. I put in a new battery. With the plugs removed I engaged the starter. The oil pressure came into the green after about 20 revolutions of the prop. I let the starter rest. I engaged the starter again and the oil pressure quickly rose to the green arc. The plane was buried in the back of the hangar so I didn't pull it out yet to start it.
I have had some of the old school guys tell me to put some Marvel Mystery Oil in the cylinders and let it soak before I run it. I am not sure what this would accomplish. Is this an old wives tale? I guess this is a penetrating oil that would theoretically loosen some stuff up. I am guessing there is no service instructions that deal with bringing back an old unpreserved engine back to life.
I shoved a cheepo home depot borescope camera into the cylinder holes. I couldn't really get a good view of what is going on inside the cylinders. There might have been some pitting but I am really not sure what I was looking for and the camera quality was very poor.
Any advice would be appreciated. I plan to pull a cylinder but it will likely get ferried home first.
