lifendet Posted December 21, 2018 Report Posted December 21, 2018 (edited) Cruising at 14k with a 35 to 40 kt headwind oil temps 215 max. On my way back @ 15k with a 50 kt tailwind, temps kept fluctuating between 225 and would go up to 240 with no change in oil pressure or any other engine parameters. It would then fall back rapidly down to 225 after peaking. Vernatherm or oil cooler needing cleaning/flushing? Cowl flaps had no effect on temp when adjusted. Edited December 21, 2018 by lifendet More info
Bob_Belville Posted December 21, 2018 Report Posted December 21, 2018 CHTs? Oil level? Did you add between legs? OAT for each leg? FF? How far ROP? A non-turbo engine will be pretty low HP at those altitudes. Engine can't sense wind. Vernatherm probably is set to close at 185F. Easy to check its operation. But it's possible the seat needs reaming. 1
lifendet Posted December 21, 2018 Author Report Posted December 21, 2018 2 hours ago, Bob_Belville said: CHTs? Oil level? Did you add between legs? OAT for each leg? FF? How far ROP? A non-turbo engine will be pretty low HP at those altitudes. Engine can't sense wind. Vernatherm probably is set to close at 185F. Easy to check its operation. But it's possible the seat needs reaming. CHTs was low 300s...No oil added between leg, oil was 6 when I returned from final leg. Oat - 3c and FF 8.1..
carusoam Posted December 21, 2018 Report Posted December 21, 2018 If you are seeing a step change of 15°F coming and going... expect the vernatherm to be at fault... That is the temperature control valve that is supposed to open and close over a range... Sounds like it may be getting stuck...? If it were the oil cooler needing a flushing... the cooling capacity would be a one way trip... not fluctuating up and down as described... Great discussion to have with your mechanic... Best regards, -a- 1
Bob_Belville Posted December 21, 2018 Report Posted December 21, 2018 1 hour ago, lifendet said: CHTs was low 300s...No oil added between leg, oil was 6 when I returned from final leg. Oat - 3c and FF 8.1.. Okay Troy(?), with CHTs where they should be at the low power setting at 15000' I'd make sure that the oil temp gauge was accurate. And I'd examine the baffle seals carefully for leaks. Sometimes the seals get folded outward which reduces the pressure above the engine. The oil cooler needs a pressure differential for efficiency. The fact that the cowl flaps do not affect temps might indicate that the problem is not the low pressure side but the high pressure side. If seals are okay you might need to check vernatherm. (Curious, why climb to 14,000 to get to a 40 kt headwind? Weather? Turbulence?)
Guest Posted December 21, 2018 Report Posted December 21, 2018 Oil temp gauge, probe or wiring should be the first checks. Clarence
bonal Posted December 21, 2018 Report Posted December 21, 2018 6 minutes ago, M20Doc said: Oil temp gauge, probe or wiring should be the first checks. Clarence Was my first thought, I took vernatherm 101 at LASAR and its not likely going to give you variable temps and if it were stuck open and no flow was reaching your cooler your temps would not come down and would likely be higher than 240
bonal Posted December 21, 2018 Report Posted December 21, 2018 Vernatherm don't usually stop working and was told very unusual for them to stick. Common problem is a worn seat in the engine or a worn plunger on the valve. But still would give you consistent temps albeit higher temps.
N201MKTurbo Posted December 21, 2018 Report Posted December 21, 2018 I flew to Dallas last week. I know that wind!
EricJ Posted December 21, 2018 Report Posted December 21, 2018 18 minutes ago, bonal said: Was my first thought, I took vernatherm 101 at LASAR and its not likely going to give you variable temps and if it were stuck open and no flow was reaching your cooler your temps would not come down and would likely be higher than 240 I was having just higher oil temps than I liked, often near the top of the green arc and sometimes approaching exceeding it during climb. It wasn't very consistent and the cowl flaps still made a difference. Changing the vernatherm fixed it. Maybe it was stuck partially open or something. I think this is one of those things that can be hard to pin down without just attacking it. I thought the vernatherm would be an easier and less risky change than poking at the oil cooler, so we took that approach and fortunately it worked out in my case. 1
lifendet Posted December 21, 2018 Author Report Posted December 21, 2018 1 hour ago, Bob_Belville said: Okay Troy(?), with CHTs where they should be at the low power setting at 15000' I'd make sure that the oil temp gauge was accurate. And I'd examine the baffle seals carefully for leaks. Sometimes the seals get folded outward which reduces the pressure above the engine. The oil cooler needs a pressure differential for efficiency. The fact that the cowl flaps do not affect temps might indicate that the problem is not the low pressure side but the high pressure side. If seals are okay you might need to check vernatherm. (Curious, why climb to 14,000 to get to a 40 kt headwind? Weather? Turbulence?) Below 14k winds was even worse and turbulence was no fun. 1
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