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- Nov 14, 2007
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Hey guys I have a question that some of you motor heads might be able to shed some light on? My engine is an early O-360 A2A narrow deck, a 59 model with a three digit Serial Number. It is a very early engine, now with 5451.9 hrs TTSN. About 1000 hrs since Overhaul. I have put over 2700 hrs on this engine myself, Gibson channel chrome cylinders that uses oil, about a qt every 3 to 4 hrs, likes to run at about 6 qts. Coming back from the Arlington WA Airshow this last week end, the engine seems to have developed a subtle/mild vibration, a bit bore than usual. Oil pressure cold 73 psi hot 68, @ 2450-2500 rpm idle 750 rpm 50 psi hot. Oat on the ground 75-80 in the air at 6500' Oat 60 oil temp top of the green 90-95, all four EGT's close to each other @ 2450-2500 with about a 20 degree spread at the most, Sensenich 76-56 with a spacer, and the rpm restriction of 2150 to 2350. and in this range, I have always had a bit of vibration, that is subtle. But I now have been feeling it in the rudder pedals at 2450- 2500 rpm, and never seemed to before?
I have some louvers on the top cowl behind the accessory section to let the heat out when on the ground, that broke loose on one side during the trip home , and thought this might be some of the problem/vibration fixed them flew the airplane today but fixing them did not seem to make much difference drained the oil, nothing in the lower or upper screen? The engine mounts are old, but are the soft C-172 style, and do not seem to be worn or loose. Exhaust is a four into one Mooney, perhaps something might be broken inside the muffler, the outlet exhaust pipe is a nice light gray and seems to run clean for an engine that burns oil, doesn't foul plugs and is not making any metal, your thoughts would be much appreciated? Or maybe it is just me as an old guy? Had a friend that flew Ag Cats with the 1340 600hp engine and once he started flying the C & D model with the PT-6 turbine, said, you know it just doesn't feel right unless your feet are vibrating on the rudder pedals!
Any real world thoughts would be much appreciated? Dave
I have some louvers on the top cowl behind the accessory section to let the heat out when on the ground, that broke loose on one side during the trip home , and thought this might be some of the problem/vibration fixed them flew the airplane today but fixing them did not seem to make much difference drained the oil, nothing in the lower or upper screen? The engine mounts are old, but are the soft C-172 style, and do not seem to be worn or loose. Exhaust is a four into one Mooney, perhaps something might be broken inside the muffler, the outlet exhaust pipe is a nice light gray and seems to run clean for an engine that burns oil, doesn't foul plugs and is not making any metal, your thoughts would be much appreciated? Or maybe it is just me as an old guy? Had a friend that flew Ag Cats with the 1340 600hp engine and once he started flying the C & D model with the PT-6 turbine, said, you know it just doesn't feel right unless your feet are vibrating on the rudder pedals!
Any real world thoughts would be much appreciated? Dave
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