Hey Guys, Back near the end of May I decided to pull the engine for an overhaul for a couple reasons. For more years than I can remember I have had a oil leak which I knew was from a crack in the block. While this may sound very on safe it never became a structural issue but only caused me a large amount of cleaning and adding a quart every10 to 12 hours of operation. This past winter it became apparent that the leaking was increasing to the point that it became a real irritant. The thing that made the deciding factor was during a afternoon flight I noticed a drop in oil pressure while nearly a hour from home. I never lost pressure but the lowered pressure was a another cause for concern. I always felt that an accident is a build up of 3 mistakes and I had 2 already. I had a block preped by Roy a few years ago and I had a store pile of parts so I figured a several week turn around and be right back at it. Well, that didn't work out so well. Through a number of comedy of errors (not really funny) and 4 separate tear downs and test runs and even a couple test flights, I finally have everything running great again. The first big deal was I knocked the block off the work bench when it was short block assembled. From there i convinced myself that it had distorted the block and it was trashed. MArk Lankford came to the rescue by sending me his 3100cc block. I built that all the way up and mounted it to the plane. I knew that it was very tight build. It proved to be to tight with high oil temps and scorching a bearing that was tight. So back off the plane and tear down again. I tore the high volume oil pump apart again and looked the gears over again. There was no sign of wear at all but using a magnifying glass I noticed that there were some circular scores just above the drive gear. The drive gear is a pressure fit to the shaft. It appears that the gear when up to temps became loose on the shaft and would slip some. I replaced the drive gear and hoped I had this resolved. Over this period of time I re-evaluated the case that I had dropped from the work bench. Other than a dent in one corner of the casting I could not find any misalignment or damage at all. I re-installed 2 different cranks and cams to torque and found that the cranks run perfectly true and free. So I took everything back off Mark's case and started to rebuild mine again. At least Mark's is all cleaned, painted and ready for him to start his rebuild. I built this one up again and mounted it to the plane again. This time it seemed to go together OK. A couple more weeks altogether and mounted it back up to the plane again. It started up OK and timing was checked. Something bothering me...It didn't sound quit the same. I did a test flight of about 20 minutes around the pattern and it still bothered me. I had one head temp that was a bit high. But worse yet I had oil all over things again... That just isn't going to due again. I cleaned the engine all up again and put the dye in the oil that ultraviolet light shows. I ran the engine on the ground up to temps for about 15 or 20 minutes. My son and I pulled the engine again, took it home back on the bench and search out the oil leaks with a black light in the dark. To my surprise none of the leaking was coming from where I thought it was. I only had one O ring on one push rod tube that was leaking a bit. All the rest was coming from the edges of the top cover. Well at least it was an easy fix for that part. The noise that was troubling me was the next thing. I just had an uneasy feeling about the valve adjustments. When I pulled the cover on the right side I found the middle rockers loose on the push rods. I had miss adjusted a least one set somehow (inept or incompetent come to mind) I did not even bother checking any others. I pulled both heads off, push rod tubes pulled out the lifters. I took each lifter apart in order and drained them and replaced them in order. Reassembled the right and then the left sides with all new O rings again. I carefully adjusted the lifters in order and repeated to verify. The oil with the dye was left in the oil pan just in case I discovered leaking again when it was back on the plane. The engine went back on again yesterday. Everything went well which made the process feel better. Nothing seemed to be nagging me this time. I finaled everything out this morning and with my son at the throttle we checked the timing again. The engine fired right up with just a couple cranks and ran very smooth. Nothing bothering me this time... sounds great and seemed like it had great power. After a few minutes of running and warmed up there was no obvious oil leaks either. I got everything all cleaned and back under cowl. Started her up again and did a bit of taxi. Really acting great now and very good power. I decided that the only way to really find out was to fly. The take off was good with all temps being very normal as compared to the past 12 years. I flew for an hour with one full throttle run at 3000 feet just to see what happens. Like I said the power seems really good. At 3250 rpm she was bouncing the true airspeed at 183 to 184 mph a solid 3 to 4 better than i have been able to achieve before. I didn't mention the details of what was actually done in the rebuilds. The main bearings and rod bearings were replaced. The exhaust valves replaced. All valves were lapped. pistons removed and inspected, rings inspected cleaned and re-installed. New fifth bearing shell installed. New plugs. New oil pump gears. New silicon exhaust gaskets. New cylinder head and base gaskets. Mostly all new instrument sensors. all new gaskets. New bypass spring and piston. Replaced spark-plug wires. Lots of cleaning and rechecking every part for condition. All in all if it wasn't for the oil leak that has plagued me I would not have been afraid to have run this engine to 1500 hours or beyond. There was a period of times during the past 6 months that i was ready to call it quits, This rebuild was about the most frustrating thing that I have ever done. I fully admit that several of the things that went wrong were fully and completely of my own making. But I flew my plane today and man oh man does it make it all worth while. Keep building guys, The sky is waiting, Joe Horton, N357CJ
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