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About FlyBoyM20J

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    1982 M20J

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  1. I'm going to keep a *very* close eye on JPI data to see if there is any more sticking of C2 EV, but I wonder if it was just a shipping contamination or something. C4's EV was, in fact, also stuck when we did the post-runup compression check of C2 that led to 76/80. I suggested we test C4 just as a reference, and lo: C4 read back about 40/80. No JPI graph has ever shown C4 to be stuck, but some of the EGT traces for C4 do show the sticky valve signature. So, my A&P and I were already planning on doing the "rope trick" on C4 and will also do C2 if JPI indicates it has any further issues. This will probably be in a few weeks. We've had enough excitement for now and I want to collect JPI data for a while post-GAMI. As for GAMIs, they are not yet installed. I will do one more 1.5-hour break-in flight with the old injectors tomorrow morning, then tomorrow afternoon, my A&P and I will install the new GAMI injectors. I'm doing all this burn-in ROP (or right at peak) so I have only my last year's history of LOP to reference post-GAMI, but so it must be. I didn't know that I was expected to install the GAMIs, then collect data, and then potentially swap injectors...I will certainly be collecting data for every single flight and am eager to see what GAMI does for my LOP stability (it was OK with stock injectors but I often couldn't go past 20F LOP before the engine ran rough).
  2. Cylinder 2 installed. Not 100% without issues - first compression check revealed the new exhaust valve was leaking terribly. We staked it; then the only leak was around the rings into the crankcase (as expected). After a run-up, it read 76/80, so we put everything back together and I took it for a burn-in flight early today. 1.5 hours at 25 square. C2 traces are in green in the JPI graph attached. You can see the CHT drop at 08:16:49 (vertical marker) just after I leaned again for max power. I believe this is when it sealed. The C2 EGT trace (bold green) is beautiful. Break-in oil is Philipx X/C 20W50. I will do at least 1 more of these break-in flights and will change the oil at 10 hours. GAMI injectors go on tomorrow. It is good to be flying again. This plane is back to 100% awesome!
  3. Further update...the cylinder is back in my hands! Less than $600 total for the work and return shipping. Thanks to Sam and David Jewell for a fast and friendly turnaround on this. My AP and I are going to install it, the muffler, and the new GAMI injectors tomorrow. I can hardly wait to get back in the air!
  4. Don't forget to unplug the landing light before you walk away with the lower cowling. Oh, and it's always a good idea to remember to plug the landing light back in once the lower cowling is back in place...but before the upper cowling is attached. This is what I think I'm going to tatoo on my arm in some fashion.
  5. I'm reading this carefully, thanks! Lucky for me, I do most of the work on my plane alongside my A&P, so I am going to be directly involved when we re-install the cylinder we pulled due to the bent pushrod (other thread) last week. I do trust my mechanics but everyone makes mistakes and I prefer to double-check things in person.
  6. Ross, this is my understanding, as well. I have ordered 3 different sizes of pushrods to have on hand when the cylinder is returned to me. 15F19957-56 (13.061") 15F19957-57 (13.088") <-- this was the size that was already in there 15F19957-58 (13.115") These are the original Lycoming part numbers, which as per SI1060T have been superseded. But given I have an older pushrod driving the intake valve in this cylinder (and it has no P/N stamped on it), I have opted not to risk mixing a new pushrod P/N with the intake one in case they are the same length (prohibited in the SI). Cliff SI1060T Push Rods.pdf
  7. Minor update. The cylinder is with Jewell Aviation. I called this afternoon and Sam answered. He happened to be working on it when I called. He said nothing was wrong except that the valve guide must've gotten some debris (or just carbon buildup) in it and that the valve stem was quite worn. So he is going to replace both the guide and the valve and that will be all it takes. At least, I believe he said he would replace the guide; I know he said he'd replace the valve, so maybe he's just reaming/grinding the guide. Sam did mention that the wobble test would have revealed a problem with this valve. Oh, and on pushrods: he said you generally get to use the same length rod that was originally there, especially when you both service the guide and replace the valve...that's where I think he must be just reaming/grinding the guide but replacing the valve. The combination gets you back to where you started, more or less, in terms of pushrod length. He said the cylinder itself looks very good, especially for 1450 hours. No cracks, nothing. He asked if I wanted new rings and suggested that I do so given the hours on this cylinder. I agreed, and asked him to mount the piston back in the cylinder before he ships it back to me. Sure thing, he said, and that was that.
  8. 2 of the leads on mine were loose enough that they might have just come off the spades if I'd done this during flight. I'm rather glad I tried it on the ground first!
  9. All it took to get rid of this was for me to get under the panel and remove all 4 spade connectors from the back of the master switch, use need-nose pliers to tighten up a couple of them, then push them all back on. Presto, ammeter was steady as a pet rock and all incandescent lights stayed more or less the same intensity. I think this also made my electric turn coordinator start working more predictably. It never flagged an error but my timed standard-rate turns were all over the clock until I did this fix, then I started getting more like 3 degrees/second at the indicated bank angle.
  10. I had this problem...first noticed it when I started flying my (new to me) 1982 J at night and the panel lights were dimming as the ammeter needle fluctuated. I posted about it and it turned out to be this:
  11. I have been looking back through my JPI logs to determine the first point at which I can see that C2 is not well. I would say it was this 3.5-hour flight on 23 NOV 2018. One thing I note is that "approach sickness" (sticky valve on approach) seems to occur many flight hours before "morning sickness" (sticky valve at startup) starts for this valve. If you click and zoom in, you can see one "approach sickness" dropout for the C2 EGT trace. Here's short flight for IFR approach practice on 04 JAN 2019. Notice the C4 EGT is unstable at startup but tends to drop out on approach cooldown: By 14 FEB 2019, we start to see "morning sickness": Here's 20 MAR 2019: 06 APR 2019 I looked at some of these over the winter and I really thought the "dropouts" at approach and later at startup indicated a loose thermocouple connection. But if I view them in the context of the noisy trace for C2 EGT at cruise and later the rough starts, it should have been obvious what was happening. I just noticed the cycling of C2 CHT. That's important, I'm sure. And I should mention that up until mid-April 2019, I had the EDM-700 configured for its default sample rate (about 1 sample every 6 seconds). About 3 weeks ago, I switched it to its highest rate (3 samples/second if I recall) and that has helped me see the sawtooth pattern of C2 EGT at cruise. I knew something was up and was about to do some real analysis but it turns out I was already out of time. How much warning did I really have if I'd been paying attention? It was about 40 hours between that first flight with noisy C2 EGT on 23 NOV 2018 and the final event that bent the rod. It was about 20 hours between the time the JPI logs show first morning sickness and the bent rod. As Mike Busch says, “Anyone who experiences an in-flight exhaust valve failure today just wasn’t paying attention.” This is 100% correct in my case. Cliff
  12. Thank you, Clarence! If I understand this correctly, a different length push rod than the original might need to be used any time a valve or seat is reground, regardless of whether the original rod was damaged. In my case, all of that is up for grabs, so to do this properly, I should buy a few sizes of pushrod, and test for min/max as found in SSP-1176-4. For IO-360, we'd be Chart S, so it looks like min is 0.028 and max is 0.080... inches, I assume.
  13. Just pressed out the wrist pin so now the piston is free. Picture below. It's easy to see the point where it impacted the exhaust valve now. I also inspected the bent rod a bit more carefully and it has numbers stamped on it. I hope this enough to find a replacement. 15F19957-57 ON972 31-97 This seems to be it!
  14. In this video on rebuilding the IO-360 (should be linked to the correct time for this section), they seem to suggest that rods of different lengths might need to be tried empirically in order to get the correct fit as referenced by a go-no-go feeler gauge. I guess my worst-case situation is that I must buy 4 different rod lengths and try them, but then I'd also need the GnG gauge. I've attached a picture of the piston face, as well. I'm not sure I see any unusual marks.
  15. I have a hand drill and can do it that way with the wood die held in a vise. Might be a better idea given how bent the thing is and I'm not sure the lathe or the drill press can be slowed down sufficiently. But it is a handy machine. I'll call David first. Maybe he prefers to straighten it and measure it himself. I just need to get a replacement, so it's all good either way.