Bartman Posted July 20, 2020 Report Share Posted July 20, 2020 On 1/30/2020 at 1950 SMOH we made a decision to remove the cylinders and rebuild them and keep on flying. This was based on excellent compressions and nothing coming our of the crankcase vent tube, and had there been no oil leak I would have kept on flying and otherwise confident with the engine. One of the thru-studs on the #1 cylinder was leaking and I just couldn’t stand it anymore. Everything looked great after removing #1, #2 and #3 but when we removed #4 we found a worn cam lobe and beat up lifter. I’m no expert, but the lifter looks like it was beating the camshaft lobe and I think I had a sticking valve. We decided to do a field overhaul and use DLC coated lifters with a new camshaft. After disassembly and decision making we sent the usual components to the specialty shops, and shortly after that COVID-19 hit around March 12th, and progress ground to a crawl. The A3B6D case had fretting and we were skeptical whether it would pass, but that was nothing compared to the cracks they found and was deemed not serviceable. I considered a new case and roller tappers, but that is not cheap and if you are going to do that it would have been better to send if to the factory and hope they would exchange it and go A3B6. We located a serviceable case and proceeded with the rebuild, but with COVID-19 we were moving at a snails pace in March and April and even into May but then things improved. My A&P-IA finished the engine and I took delivery on May 25th. I personally did the complete engine installation by myself with regular inspections of my work. Only needed help with 3 things including torque the mounting bolts to the frame and to the firewall, installation and safety tie the propeller, and although I was close using the timing marks but I needed help with fine tune timing of the Single-Dual magneto. I only work every other week and this gave me a lot of time to work, but still there were delays like hoses and oil return tubes, and then of course the fuel hoses and contamination in the flow divider as documented in another thread. I kept a running list of things that needed to be tightened, completed, checked and torqued and used a roll of painters tape with notes for myself and the IA so we remained on the same page. We used all new hardware, and I jokingly think I changed the weight and balance with all of the new Adel clamps and fasteners. I kept telling myself vibration is the enemy and everything is very secure. 3 Quote Link to comment Share on other sites More sharing options...
carusoam Posted July 20, 2020 Report Share Posted July 20, 2020 Sounds like you got the full use out of the engine... I put an arrow on your lunar surfaced cam follower... For anyone not familiar... Great pic! Great descriptions... Good luck with the next steps... Best regards, -a- Quote Link to comment Share on other sites More sharing options...
Bartman Posted July 20, 2020 Author Report Share Posted July 20, 2020 On 7/15/2020 I went for my first flight, and although my maintainer who did the engine rebuild and my inspections wanted to fly with me but I said no due to COVID, not so much due to fear for myself but more to protect him and really both of us. Having done the installation myself and also having supreme confidence in the rebuilder I had no anxiety and after a short run-up and seeing the oil temp gauge start to move I took off. Temps were nearly 375 by the time I leveled at 1500 AGL, but within 15 minutes they were down to 332 and 331 for the hottest cylinders 3 and 4 but #1 was only about 295, all with flaps open. I leaned and #2, #3 and #4 came up as expected, but on #1 the best I could get was 330 while the others were 360-370 all at 75% power settings. The second hour i alternated 65-75% every couple of laps at different RPM and MAP settings and even closing the cowl flaps Temps were great but #1 could only get 330. On the ground the oil screen had a few tiny bits of gasket material but no metal. There was a small oil leak just a couple of ounces and just enough to make a little mess from the oil filter gasket and I attribute that to putting it on hand tight to keep things clean and taking it off several times during my installation, and in retrospect maybe I should have tossed that one and used a new filter. Maybe the gasket has a piece of debris or got some oil on it and it is supposed to be tightened dry. Anyway the Tempest oil filter had nothing on the magnet and only some shiny metal dust deep in the valleys of the filter material. The second flight I ran at 75 to nearly 85% first hour with flaps closed and got the same temperatures, then alternating 65-75% the second hour. Today the third flight was again at high power and in the 4.1 hours after the first oil change I used about 3/4 to a full quart. All said and done I am very happy and have a grin on my face for the past 4 days that won’t go away. 2 Quote Link to comment Share on other sites More sharing options...
carusoam Posted July 20, 2020 Report Share Posted July 20, 2020 Low CHT after engine installed... is highly likely a sensor issue.... check and see if it is seated like the others.... And which cylinder has the ship’s gauge sensor vs. the engine monitor sensor... Best regards, -a- 1 Quote Link to comment Share on other sites More sharing options...
Bartman Posted July 20, 2020 Author Report Share Posted July 20, 2020 The only concern I have is the oil temperature. Before the rebuild it ran right in the middle of the gauge in cruise power, but now only about 1/3 the way into the green as seen in the attached picture. I know the sensor and indicator are 43 years old and have not checked with a known accurate gauge. Quote Link to comment Share on other sites More sharing options...
carusoam Posted July 20, 2020 Report Share Posted July 20, 2020 At the low end of the green range is usually a good sign... Did you have any work done on the oil cooler, vernatherm, or Oil hoses? There are a couple of discussion going on around here related to high oil temp... Mike Patey, the Draco guy, did an interesting piece/video on how vernatherms work for his new plane, scrappy... Of course his nice oversized oil cooler is mounted 15 feet behind his firewall.... highly over engineered, because he can... Best regards, -a- Quote Link to comment Share on other sites More sharing options...
Bartman Posted July 20, 2020 Author Report Share Posted July 20, 2020 3 minutes ago, carusoam said: Low CHT after engine installed... is highly likely a sensor issue.... check and see if it is seated like the others.... And which cylinder has the ship’s gauge sensor vs. the engine monitor sensor... Best regards, -a- I was thinking the same thing with the Oil Temp above most likely. My #4 EGT probe did not survive and the ship CHT is on #3 with the piggyback not the spark plug sensor. Might be time for the JPI EDM 900 2 Quote Link to comment Share on other sites More sharing options...
Bartman Posted July 31, 2020 Author Report Share Posted July 31, 2020 I found the cause of my low CHT on Cyl #1 and it was my own fault and when I discovered it I felt like a dumbass. When I was cleaning up the hangar I had a bunch of cardboard boxes to dispose of and under the flap on the bottom of the box that my baffles were in I found it. There it was, a small rectangular piece of baffle under that cardboard flap that goes in front of Cyl #1. After installing it I flew full power for another hour, and another hour alternating 65-75 while LOP. Now all 4 Cylinders are normal and I have used zero oil in the past 3.5 hours. My GAMI spread was 0.5 initially and after switching #1 and #3 the richest and leanest I am now 0.1 GAMI spread today. Magneto check at 50deg LOP was good and I am very happy ! 1 Quote Link to comment Share on other sites More sharing options...
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