Blown head gaskets? Bent intake/exhaust valves? Warped heads due to improper torque sequence? How do you know the case is where the "air" is going?
Best of luck with the Root Cause Analysis (just an engineering thing, don't sweat it) -----Original Message----- From: krnet-boun...@mylist.net [mailto:krnet-boun...@mylist.net] On Behalf Of Mark Jones Sent: Wednesday, April 25, 2007 5:24 PM To: KRnet Subject: KR> Re: Aborted Takeoff Follow Up. N886MJ made a flight yesterday after it's aborted takeoff the day before. What I did prior to the flight was to adjust my Ellison carb which was way out of whack. I had previously set up the carb for cold weather flying and she would not idle in warmer weather so I made some adjustments. I achieved a very smooth idle at 900 rpm and also regained my static rpm of 2750. As I taxied out yesterday, everything was green to go. Static rpm hit 2750. She cycled through all rpm ranges very smooth. Everything felt good so I called the tower and was cleared for takeoff on runway 28. This was about 6:30 last night and there was no one else moving on the field. As I slowly firewalled her she quickly began picking up speed. As I reached rotation I was at 3000 rpm and she lifted off like she really wanted to fly. Everything felt great and I was headed straight out due west over the interstate. As I passed through 800 feet, I took note that the oil temp was at 190° and oil pressure was at 28 psi. Then I started noticing an rpm drop. I checked the throttle to make sure it was not backing out and checked the mixture. At the same time, I called the tower and informed them that I was turning crosswind and would like to stay in the pattern and I was cleared to do so. As I was turning crosswind, the rpm dropped to 2500 and began running rough. I called the tower and informed them I was losing power and would like to turn in to runway 10 for a 180° straight back to the runway. That is when the tower asked if I was going to need assistance. It's nice to be in good with the tower as they know me and did not ask if I was declaring an emergency. Anyway I told the tower that I would be able to make the runway since I still had enough power to maintain flight (but I really did not know how long that was going to last). When I had the runway made, I throttled back and set her down on runway 10 and the tower asked if I would need tow assistance. Luckily, she was running fine at 1500 rpm and I taxied in under my own power. Once again, I beat the odds. I pulled the cowl off and the engine was so hot, I could have fried eggs on top of it. As a matter of fact, I was cleaning the prop off and the overspray from the cleaner sizzled when it hit the engine. Today, I went to the hangar and took a look. I did a cold compression test and got the following: 1 = 80/78 3 = 80/60 5 = 80/54 2 = 80/46 4 = 80/74 6 = 80/62 Not good in my opinion. All the air was escaping into the engine case and none through the intake or exhaust. This told me that either I had cracked rings or cracked pistons. So I began disassembling the engine. I have removed both heads and have pulled all jugs and removed all rods and pistons from the crank. That is about as far as I have gotten as I had to stop to go to Daddy's Night at my daughters school. I will say that the rings were not cracked. I have not removed the rings from the pistons yet to inspect the piston. The rod bearings looked like new so there is no problem there. I will continue with the disassembly and do a complete inspection and rebuild. I will beat this devil riding on my shoulder!!! Mark Jones (N886MJ) Wales, WI Visit my web site: www.flykr2s.com E-mail: flyk...@wi.rr.com _______________________________________ Search the KRnet Archives at http://www.maddyhome.com/krsrch/index.jsp to UNsubscribe from KRnet, send a message to krnet-le...@mylist.net Post photos, introductions, and For Sale items to http://www.kr2forum.com/phpBB2/index.php please see other KRnet info at http://www.krnet.org/info.html
