gusve
Well-Known Member
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Today our A&P class went to Penn Yan facilities to get a tour of the facilities and learn more about reciprocating engines. Being an owner myself, I had more questions than time allowed and I can tell you, the experience was very enlightening for me. Keep in mind I'm not associated in any way to Penn Yan Aero.
Our class met the general manager of the facility on the receiving side of the shop. Shelfs were lined up with engines ready to ship...as soon as they receive payment. The place is much smaller that what you can percieve by their advertising on most aviation magazines but is adecuate for an engine ovehaul facility. They started around 1945 If I remember correctly. The engine get identified and the disassemble starts. From there they put it in the washing machine were they use various methods to clean all parts. Then it goes to NDI to check for cracks and then measuring. The engine gets in a cart were all part that are serviceable get organized and for some engines red tags on out of limits parts. He explained that even though is legal to serviceable limits they only use new limits or basically what Lycoming will use as new in their factory. Cylinders can get over bore only 10/1000 over and have to be done in pairs to mantain balance. A 4 cylinder Lycoming engine can be overhaul completely in about 12 hours. Continental may have to wait for parts and usually takes longer. They also have a water brake dyno were they test the engine for at leat 90 minutes and 30 of those at redline or full power. Break in still has to be done by the customer. Everything gets balanced prior to assembly.
Now with my questions. Keep in mind they might go againts what we hear all the time, but this guys have a long time experience so I weight that more than some of the stuff I know and learn before.
1. I asked about what oils they recommend? Straight oil is better than dual sice it is accomplished by polimers added to the oil, they "grow" with heat but keeps doing it the more your engine heats up. He said is the #1 cause of valve getting stuck due to cristalization on the guides. Is like making diamonds with heat.
2. This one surprised me. Power flow exhaust. Not worth it for the benefits vs cost.
3. Cam Guard, same boat, just not an added benefit other than the company selling to you for profit.
4. Mogas STC. Not enough octane to burn completely and they can tell at disassembly that you used cause it stinks and change color on cylinders and pistons. It also accelerate corrosion cause it have lots of water in it.
5. As you probably know the part with most issues on our engines...the camshaft and the corrosion it gets. The cure, fly your plane long enough to burn moisture crankcase. NEVER start for 10 or 15 minutes only and NEVER EVER turn the prop to cycle the oil. Corrosion start on dry cylinders.
6. Roller rockers vs regular ones and port and polish of intakes and internals. Again not worth it and he said may as well throw money on the ground.
7. New parts from Lycoming are not always true. When measures are taken some of the part have to be machined by them. Crankcases are not always straight.
I can continue but I rant enough. What are your thoughts? I know the post was long but reply if you have more questions and let the argument begin...[emoji6]
Today our A&P class went to Penn Yan facilities to get a tour of the facilities and learn more about reciprocating engines. Being an owner myself, I had more questions than time allowed and I can tell you, the experience was very enlightening for me. Keep in mind I'm not associated in any way to Penn Yan Aero.
Our class met the general manager of the facility on the receiving side of the shop. Shelfs were lined up with engines ready to ship...as soon as they receive payment. The place is much smaller that what you can percieve by their advertising on most aviation magazines but is adecuate for an engine ovehaul facility. They started around 1945 If I remember correctly. The engine get identified and the disassemble starts. From there they put it in the washing machine were they use various methods to clean all parts. Then it goes to NDI to check for cracks and then measuring. The engine gets in a cart were all part that are serviceable get organized and for some engines red tags on out of limits parts. He explained that even though is legal to serviceable limits they only use new limits or basically what Lycoming will use as new in their factory. Cylinders can get over bore only 10/1000 over and have to be done in pairs to mantain balance. A 4 cylinder Lycoming engine can be overhaul completely in about 12 hours. Continental may have to wait for parts and usually takes longer. They also have a water brake dyno were they test the engine for at leat 90 minutes and 30 of those at redline or full power. Break in still has to be done by the customer. Everything gets balanced prior to assembly.
Now with my questions. Keep in mind they might go againts what we hear all the time, but this guys have a long time experience so I weight that more than some of the stuff I know and learn before.
1. I asked about what oils they recommend? Straight oil is better than dual sice it is accomplished by polimers added to the oil, they "grow" with heat but keeps doing it the more your engine heats up. He said is the #1 cause of valve getting stuck due to cristalization on the guides. Is like making diamonds with heat.
2. This one surprised me. Power flow exhaust. Not worth it for the benefits vs cost.
3. Cam Guard, same boat, just not an added benefit other than the company selling to you for profit.
4. Mogas STC. Not enough octane to burn completely and they can tell at disassembly that you used cause it stinks and change color on cylinders and pistons. It also accelerate corrosion cause it have lots of water in it.
5. As you probably know the part with most issues on our engines...the camshaft and the corrosion it gets. The cure, fly your plane long enough to burn moisture crankcase. NEVER start for 10 or 15 minutes only and NEVER EVER turn the prop to cycle the oil. Corrosion start on dry cylinders.
6. Roller rockers vs regular ones and port and polish of intakes and internals. Again not worth it and he said may as well throw money on the ground.
7. New parts from Lycoming are not always true. When measures are taken some of the part have to be machined by them. Crankcases are not always straight.
I can continue but I rant enough. What are your thoughts? I know the post was long but reply if you have more questions and let the argument begin...[emoji6]
