My engine decided to lock up.
in 912 / 914 Technical Questions
10 years ago
Hoping for some guidance. I just started flying my new Highlander the last two days and it has run great except for some vibration between 3000-4500. Engine is a 912ULS (1107 hours TT)(4 hours on overhauled gearbox). Engine has been on this plane only 4 hours. Yesterday when I went to the hangar in the morning to fly I pulled the prop through and there was small "catch" as I pulled the prop, but it went away on the next rotations. I flew for 2 hours making 10 takeoffs/landings. The vibration seemed more pronounced at 2500-4500 this day, but went away above and below that. The idle is set at 1900, but it did die on me a couple times on rollout when indicating 2000 on the tach. When I was done flying for the day I pulled the prop through to see if the "catch" was there, but it wasn't and the prop pulled through smoothly and oil returned to the tank. Fast forward to today I went to the hangar and this time when I pulled prop it went about 30 degrees in one direction and stopped, I could rotate it back about 30 degrees the other way where it stopped again. The way it feels when the prop stops turning is like something is stuck in a gear. Here is the list of things I have done so far and would appreciate any ideas where to look next.
1- Pulled all the top plugs/rocker covers and verified the pistons and valves are moving in the cylinders when rotating the prop back and forth.
2- Pulled the starter, gear teeth are good and turns freely.
3- Pulled the gearbox-spins good and crank gear is good.
4- Turned the bolt on the back of engine and it still stops in the same spots.
5- Used a flashlight and mirror to see if anything is hung up in the stator housing, did not find anything.
It is quiet when I rotate it back and forth, no gears grinding, just the sound of crank and pistons moving. I believe the stoppage is in the accessory case by the way it feels. My next step is to pull the engine off the plane and have a look. Also, my number one cylinder cannot go to top dead center and the crank notch is about a 1/2 inch from being lined up with the crank locking hole, any ideas how I can lock the crank to remove the bolt on the back of the engine?
Thank you,
Brent Hoskins
Caldwell, ID
1- Pulled all the top plugs/rocker covers and verified the pistons and valves are moving in the cylinders when rotating the prop back and forth.
2- Pulled the starter, gear teeth are good and turns freely.
3- Pulled the gearbox-spins good and crank gear is good.
4- Turned the bolt on the back of engine and it still stops in the same spots.
5- Used a flashlight and mirror to see if anything is hung up in the stator housing, did not find anything.
It is quiet when I rotate it back and forth, no gears grinding, just the sound of crank and pistons moving. I believe the stoppage is in the accessory case by the way it feels. My next step is to pull the engine off the plane and have a look. Also, my number one cylinder cannot go to top dead center and the crank notch is about a 1/2 inch from being lined up with the crank locking hole, any ideas how I can lock the crank to remove the bolt on the back of the engine?
Thank you,
Brent Hoskins
Caldwell, ID
