Ragsf15e Posted April 8, 2022 Report Posted April 8, 2022 6 minutes ago, MikeOH said: @Ragsf15e I was at 6500 Weird. Your oil temp does seem higher than most but not like dangerous high. I’ll be interested when you figure it out. Quote
MikeOH Posted April 8, 2022 Author Report Posted April 8, 2022 @carusoam Good idea on the GoPro and tell-tales! I was trying to figure out how to determine airflow direction. Quote
MikeOH Posted April 8, 2022 Author Report Posted April 8, 2022 5 minutes ago, Ragsf15e said: Weird. Your oil temp does seem higher than most but not like dangerous high. I’ll be interested when you figure it out. When summer is full on, it runs as high as 230! According to the Savvy cohort data (22,000 flights of 413 M20F/Js) my oil temp is higher than 99%!!! 1 Quote
carusoam Posted April 8, 2022 Report Posted April 8, 2022 It’s going to be an aha! moment… when you come across the culprit… +1 for the tell tales… +1 for a thermocouple thermometer if you can put one in front of the oil cooler… If the air is running backwards through it as expected… the tell tale should be able to reveal it… use more than one in case the flow is really funnier than we expect… -a- Quote
carusoam Posted April 8, 2022 Report Posted April 8, 2022 Notes on heat exchangers… When engineers are looking at these things… They want to know as much as they can about the flows…. And temps… Oil Temp in Oil temp out Air temp in Air temp out Oil flow gpm(?) Air flow cfm After that… there a few things related to heat transfer…. Fin health… all straight… fin surfaces… all nice and clean… There may be a back plate behind the oil cooler…. By a few inches…. Make sure it is there (or not there ?)… no nesting materials hiding up inside… Got any pics you can share? PP thoughts only… -a- Quote
N201MKTurbo Posted April 8, 2022 Report Posted April 8, 2022 10 hours ago, MikeOH said: @N201MKTurbo Interesting you bring up the seat....at annual, when I had the vernatherm replaced, my mechanic said the seat was a little rough and he 'cleaned it up'. Not sure how, and given the cost of the tool, I'm wondering if that's where the problem is! That is, maybe he didn't really correct the problem. If I want to replace the seat I need an entire new oil filter adaptor as the vernatherm threads into it, I believe. You don’t need a new one, there is a tool that resurfaces the seat. Quote
Chessieretriever Posted April 8, 2022 Report Posted April 8, 2022 Does your engine have blowby? This does contribute quite significantly to increased oil temperatures and obviously is not good news. Oil consumption may be a tell tale sign; the best way to find out is to measure the pressure in the engine case during 'hot' operation (requires some instrumentation and a willing A/P to work with you). On a separate note, the oil is totally fine in the temperature ranges you are experiencing but the pistons on your engine are being cooled (underside spray jets) with a medium that is hotter than engines with lower oil temps and hence see a little more trauma in cruise (linear relationship with oil temp). I would not be alarmed at 200F to 220F just yet. 2 Quote
MikeOH Posted April 8, 2022 Author Report Posted April 8, 2022 5 hours ago, Chessieretriever said: Does your engine have blowby? This does contribute quite significantly to increased oil temperatures and obviously is not good news. Oil consumption may be a tell tale sign; the best way to find out is to measure the pressure in the engine case during 'hot' operation (requires some instrumentation and a willing A/P to work with you). On a separate note, the oil is totally fine in the temperature ranges you are experiencing but the pistons on your engine are being cooled (underside spray jets) with a medium that is hotter than engines with lower oil temps and hence see a little more trauma in cruise (linear relationship with oil temp). I would not be alarmed at 200F to 220F just yet. @Chessieretriever My oil consumption is around 1 qt/8-10 hours, so I don't think it's blowby. But, I never thought about measuring crankcase pressure. Thank you for the suggestion! Quote
MikeOH Posted April 8, 2022 Author Report Posted April 8, 2022 7 hours ago, N201MKTurbo said: You don’t need a new one, there is a tool that resurfaces the seat. @N201MKTurbo True. But, should I try again after my A&P just did this? Also, I would think any resurfacing would remove material increasing the distance the vernatherm plunger needs to travel to form a proper seal. There must be some limit as to how much can be removed before that's an issue. Since I don't know the history I'm not sure if the seat has previously been resurfaced...perhaps multiple times? Quote
carusoam Posted April 8, 2022 Report Posted April 8, 2022 Significant blow-by comes with side effects… the oil likes to entrain and entrap the exhaust… 1) If you see bubbles and foam after the flight… 2) You see really dark change of color in a short amount of time… 3) Your oil smells like exhaust…. My old O360 handed me this lesson one day… The vernatherm probably has an installation procedure for setting the distances, open and closed, from the seat… or at least when closed… or its big spring May have something to do with closing the gap properly…? inspection of the seat probably shows a shiny circle where the valve gently polishes the surface… PP thoughts only, not a mechanic… Best regards, -a- Quote
Ragsf15e Posted April 8, 2022 Report Posted April 8, 2022 1 hour ago, MikeOH said: @N201MKTurbo True. But, should I try again after my A&P just did this? Also, I would think any resurfacing would remove material increasing the distance the vernatherm plunger needs to travel to form a proper seal. There must be some limit as to how much can be removed before that's an issue. Since I don't know the history I'm not sure if the seat has previously been resurfaced...perhaps multiple times? Couple good questions above… do you have the plate behind the oil cooler to direct airflow? Also, what type of cylinders do you have? Are they chrome by any chance? Quote
N201MKTurbo Posted April 8, 2022 Report Posted April 8, 2022 2 hours ago, MikeOH said: @N201MKTurbo True. But, should I try again after my A&P just did this? Also, I would think any resurfacing would remove material increasing the distance the vernatherm plunger needs to travel to form a proper seal. There must be some limit as to how much can be removed before that's an issue. Since I don't know the history I'm not sure if the seat has previously been resurfaced...perhaps multiple times? I think a vernatherm expands quite a bit more than it needs to. I doubt the amount of metal taken off the seat makes any difference. You can look in the service manual and see what the spec is. That is why it has a spring. The spring loads the cone against the seat. The center rod keeps going after the cone is seated. If it didn't have this feature, the expansion force would probably break something. Quote
MikeOH Posted April 9, 2022 Author Report Posted April 9, 2022 3 hours ago, Ragsf15e said: Couple good questions above… do you have the plate behind the oil cooler to direct airflow? Also, what type of cylinders do you have? Are they chrome by any chance? @Ragsf15e No panel behind the cooler. And, I checked the Mooney IPC and it's NOT required for my serial number F. Other models/SNs have it. Hmm, you might be onto something with the cylinder. I'm not sure but there is a color on #2 (the one that runs hot) that is different than the other three. I can't remember if it is green and the other 3 are blue, or the other way around! Sounds like I have a few things to look at when I go out to the hangar! Quote
MikeOH Posted April 9, 2022 Author Report Posted April 9, 2022 2 hours ago, N201MKTurbo said: I think a vernatherm expands quite a bit more than it needs to. I doubt the amount of metal taken off the seat makes any difference. You can look in the service manual and see what the spec is. That is why it has a spring. The spring loads the cone against the seat. The center rod keeps going after the cone is seated. If it didn't have this feature, the expansion force would probably break something. @N201MKTurbo I guess that makes sense. The contradiction is that I thought the check was to put the vernatherm in hot water and measure how much it expands. I didn't think it was all that much, hence my concern over the seat material being removed. Quote
MikeOH Posted April 9, 2022 Author Report Posted April 9, 2022 4 hours ago, carusoam said: Significant blow-by comes with side effects… the oil likes to entrain and entrap the exhaust… 1) If you see bubbles and foam after the flight… 2) You see really dark change of color in a short amount of time… 3) Your oil smells like exhaust…. My old O360 handed me this lesson one day… The vernatherm probably has an installation procedure for setting the distances, open and closed, from the seat… or at least when closed… or its big spring May have something to do with closing the gap properly…? inspection of the seat probably shows a shiny circle where the valve gently polishes the surface… PP thoughts only, not a mechanic… Best regards, -a- @carusoam Compressions run 75 to 79/80 No bubbles or foam. No exhaust smell in the oil. Oil does get dark. How quick is too quick? And, if it's 'too quick' is that really the reason the oil temp is 40 degrees above normal?? I would think I'd have the foam and smell by the time it was that bad. And, would my compressions be that high if blowby is my issue? Appreciate your questions, none the less 1 Quote
carusoam Posted April 9, 2022 Report Posted April 9, 2022 Good compressions indicate blow by probably isn’t the issue… Turning black occurs in a couple of hours or less… Bubbles appear during the flight, so checking oil level after the flight is enough to know… Increase of oil level because of foam…. Has a tendency to put more oil out the case vent…. Burn’t exhaust smell is amazingly strong… when normal oil smell is quite benign… I didn’t have an engine monitor at the time… so probably didn’t discern a change of OilT to go with the blow-by I did have… The exhaust bubbles are EGT in scale 1500°F… so it is quite possible blow-by would raise the oil temp…. Fortunately, this experience probably isn’t related… Easy to identify, more painful to correct… Best regards, -a- 1 Quote
Ragsf15e Posted April 9, 2022 Report Posted April 9, 2022 1 hour ago, MikeOH said: @carusoam Compressions run 75 to 79/80 No bubbles or foam. No exhaust smell in the oil. Oil does get dark. How quick is too quick? And, if it's 'too quick' is that really the reason the oil temp is 40 degrees above normal?? I would think I'd have the foam and smell by the time it was that bad. And, would my compressions be that high if blowby is my issue? Appreciate your questions, none the less I’m gonna beg to differ with @carusoam… You can definitely have blowby with good compressions. The oil that sits in the bottom of your cylinders will seal them pretty good for your compression checks. But when you’re running you can still have blowby. Chrome cylinders are notorious for that. However none of that would really explain your temps being this much different than everyone else. I have three chrome cylinders in mine and it definitely doesn’t run that hot. Fyi, chrome cylinders are orange painted around them. Again, I doubt you could get the oil that warm just through blowby without noticing a lot of oil useage. 1 1 Quote
PT20J Posted April 10, 2022 Report Posted April 10, 2022 On 4/8/2022 at 5:34 PM, MikeOH said: Hmm, you might be onto something with the cylinder. I'm not sure but there is a color on #2 (the one that runs hot) that is different than the other three. I can't remember if it is green and the other 3 are blue, or the other way around! Sounds like I have a few things to look at when I go out to the hangar! Blue is nitrided; Green is .010" oversize; orange is chrome 1 1 Quote
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