Browncbr1 Posted December 16, 2016 Report Share Posted December 16, 2016 (edited) I flew over to a nearby airport early this morning. I had preheat on all night and startup and flying over was normal. I started it back up to return and temps were normal, pressure normal.. I was taxing to the run up area and i noticed rpm dropped by 50 or 100,... at first i thought maybe I was lead fouling a plug or something, then my jpi blinked red oil pressure warning caught my eye.. it was reading low 50's at about 1000rpm... after a few seconds it went away and rpm came back up with OP normal.. oil temp was about 145F. OAT 21F.. Did my run up paying close attention to OP... normal.. ... I determined that perhaps a chunk of carbon or whatever had momentarily inhibited the pressure relief valve ball from seating all the way and whatever it was had since blown through and been collected in the oil filter... so I elected to take off while keeping a close eye on OP... at 2700rpm, OP was 90.. normal.. as I climbed up over 1000AGL and reduced MP and rpm, OP reduced normally to low 80's by the time I settled on 2400/21" to cool it slowly before landing 10 miles away.. landed and taxied with about 60 OP... everything normal and making great power.. I have not removed the oil pressure relief valve for inspection yet, but I have read in the past that this sort of thing can be a symptom of not running these engines hard enough..chunks of carbon floating around in the oil.. . In another thread, I had talked a little bit about internal lead buildup and had discovered I really should be running mine a little harder, at least from time to time. Most of my recent flying has been low power shooting approaches, etc.. ... Has anyone else had similar experience? Was I negligent in electing to take off? Was I naive to come to the conclusion that I did before taking off? Just trying to get other's ideas for future reference in safe operation. Edited December 16, 2016 by Browncbr1 Quote Link to comment Share on other sites More sharing options...
takair Posted December 17, 2016 Report Share Posted December 17, 2016 What were the winds doing? Is it possible you had a significant and somwhat gusty tailwind? At low RPM, the oil pressure can respond noticeably to RPM. Perhaps try this....if you normally taxi at 1000rpm, pull throttle that same 100rpm....what does your oil pressure do? I suspect it follows... Quote Link to comment Share on other sites More sharing options...
Browncbr1 Posted December 17, 2016 Author Report Share Posted December 17, 2016 It wasn't gusty at all. This felt like leaning to the point of starting to lose power. But what got my attention is the oil pressure alert in the JPI, which I have never seen before. Not even at completely closed idle with hotter oil. I'm going to pull the data because I saw on past flights OP could be in the 40's when landing but I never saw the alert before. Weird Quote Link to comment Share on other sites More sharing options...
takair Posted December 17, 2016 Report Share Posted December 17, 2016 are you reading oil pressure from the JPI? Does it match the aircraft oil pressure? Quote Link to comment Share on other sites More sharing options...
Yetti Posted December 17, 2016 Report Share Posted December 17, 2016 Varatham valve opening? Quote Link to comment Share on other sites More sharing options...
Browncbr1 Posted December 17, 2016 Author Report Share Posted December 17, 2016 I was reading the JPI and it's difficult to say if it matches the garwin gauge exactly but I didn't see any fever able difference between the two. To be honest, I didn't cross check by the time the alert went away. I had the vernatherm replaced about 18months ago as I was trying to trying to keep oil temp down in the hot summer... Generally, that helped oil temps since then. Quote Link to comment Share on other sites More sharing options...
Yetti Posted December 17, 2016 Report Share Posted December 17, 2016 Also it would be good to know where the thermocouple are located on the engine. 2 Quote Link to comment Share on other sites More sharing options...
Browncbr1 Posted December 17, 2016 Author Report Share Posted December 17, 2016 2 minutes ago, Yetti said: Also it would be good to know where the thermocouple are located on the engine. ill double check. As far as I recall it is hooked up according to JPI install manual . I'll grab a photo Quote Link to comment Share on other sites More sharing options...
Browncbr1 Posted December 21, 2016 Author Report Share Posted December 21, 2016 After checking my jpi data, there was only a single data point that shows 47psi.. maybe it went lower than that or maybe the alarm is set for 50psi.. see attached rpm drop and oil pressure drop then come right back up. I didn't touch anything ... EGTs went down with RPM, so it seems unrelated to ignition. FF was stable as well.. hmmm... all other data looks normal flew again today with no issue. I ordered new gaskets for the oil pressure relief valve and suction screen so I can remove and clean out.. Quote Link to comment Share on other sites More sharing options...
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