Hi guys, first time posting here and I need help! Let me tell you the story.. beautiful day in western Alaska and I’m out destroying the peace in our local community. I fly around for about a hour and decided to stop on a neighboring village to get out and stretch my legs... here come the fun. I land, pull off the runway and shut down and as the prop comes to a stop, it rocks in reverse just a inch and I here a metal on metal “ting”. As I’m sitting there I think to myself I’ve never heard that before. So fast forward to jumping back in and firing up. Starts up no problem for the exception of a loud ticking sound. Something I’ve never heard before. So loud I can hear in my headset. The only way I can describe it is the sound a truck makes when it looses the exhaust doughnut. As I’m looking over the gauges everything looks good, all cylinder temps, oil pressure... I shut down and immediately call my mechanic. Think we narrowed it down to starter drive or stuck valve, I get out and look over the engine for anything obvious. Everything looks good, I pull the prop through and all feels good, and I try the opposite way and the motor immediately locks up! Like won’t go in reverse at all but you flip the blade and some stokes it will let you move freely in reverse motion. We did pull the oil filter and took it back home with us, opened it up and luckily no metal..I ended up ditching her there and now waiting on weather to get back out and drop the cowl... any ideas?

Justin-

What starter and starter adapter do you have? Combinations of old style starter adapters and new style geared starters can cause a lockup like you described. If I recall correctly, the old style starter adapter needs to rotate slightly backwards to disengage, and the geared starters don't allow that.

I have the stock starter and a “old style” starter drive, the one with the “heavy duty spring”. With that being said I just had it overhauled 300-350 hours ago

Justin-

My bet is starter drive. If it was a stuck, now bent, valve you would have a dead cylinder. Starter drive won't make metal in the filter for the minute or two you ran it for. Always important to pull your starter every so often to check how free it rotates by hand, spec is no more than 5 in/lbs. Always good practice to replace or rebuild your starter at the same time as adaptor rebuild. Very important as the starter motor needs to rotate slightly backwards after every start to relax the spring on the shaft. Just don't get anxious to get the plane back to a warm hanger, your A/P won't be excited about changing an adaptor outside in the winter, before figuring out exactly what's wrong - that short flight could cost you an engine.

(Update) Weather has been horrible out here, finally broke after 4pm(of course daylight is gone). Made it to the bird and dropped the cowl, looked for anything obvious.. everything looked good. Pulled all the valve covers, went to pull the prop, now she’s locked up in both directions of travel. I’m lost! Pulled the starter and everything looked good from what I could see and also the gears through the oil drain galley looked good. The inside of the starter drive turns freely from what I could see. Left the the plane there again... still thinking the starter drive?

Justin-

Could it be the generator or alternator with bearing gone bad?

Turning the starter drive by hand you should be able to feel the spring windup, shouldn't just be free both directions. Possibility the spring has failed completely and seized the shaft and drum together solid now that it has cooled off.

Roger, I did pull the starter and I could feel the spring wind up and felt normal as I turned the starter drive with a big flathead in The direction of the arrow printed on the starter drive

it's a bit of work, but you might try pulling the starter adapter & seeing if the engine is still bound up.

That's a weird one. Only a certain number of ways for an engine to lock solid. Seized piston in cylinder - Very unlikely, seized on main bearings - very unlikely. Gear train failure - usually a mess. Alternator - belt driven, even if seized would just slip on belt. How about the wet vacuum pump? Are they stronger shafts than the dry that just shear off? Maybe that was the exhaust leak noise you heard? Every thing "sounds" like a starter adaptor except the sound like an exhaust leak

I’ve looked over the engine good, everybody I’ve talked too including a local engine shop say start with the starter drive. Said pull it out just enough to see if I can free up the engine. Currently right now the blade will move about a foot before it locks up in either direction. Thanks your your help and input guys, can’t thank you enough for the help and pointers, I’ll let you know what I find.. have to head to work to pay for a new starter drive lol

Does it move freely that one foot of travel? No grating or grinding sounds? If so then it is not a piston or broken ring. Being only 1 ' also means it is not likely a valve issue as you would probably have more rotation before it binds up.
Does it clunk and stop dead or does it just get so tight and stop more gradual?
A few things i can think of:
a spun main bearing, if broken and binding in the cap can act this was. In this case the point that the engine stops turning may change a little.
a broken crankshaft, if broken in the web between rod and main it can be out of position enough to hit the inside of the case and will stop dead with a clunk you can hear and feel.
a problem in the accessory case, be it starter, alt, or mag. A tooth broken off a gear and jammed between the teeth of another gear might do this but I would think you would have more rotation before it stops.
I hope this turns out to be something simple and fixable, please let us know

Lots of knowledge in this thread.

Are you the guy with the white with (i think) red and blue accents '57 180? Mt prop, on the ramp at King Salmon, fly floats for branch river? I think we talked briefly during one of my stops there flying for work. Good luck! Can't say I'd be stoked about having an airplane sitting in a different village, hope you get it worked out.

-Asa

Speaking of broken crank, I wonder if a counter weight could have a problem-----maybe a snap ring fell out?????

So basically when I pull the prop it moves as it should that foot of trace but it binds up and it binds up hard to a stop. Talked to one engine shop today and they had 2 very probable answers ...

1) a bolt has failed on the cap of the connecting rod and now the bolt and or cap is hitting the inside of the case.

2) a chipped tooth in the accessory case.

Both of these sound very probable and both require pulling the motor

ASA, no that’s another guy at PAKN. Your close though, it’s a blue 57’ 180 “Big Blue”, might of seem her around the ramp once or twice..

UPDATE: well just got home from the bird, continued the battle on checking all the simple boxes. Outcome was not good. Got to the bird and pulled a mag and stuffed a bore scope down the accessory case from the top... everything looked great, next pulled the starter drive and continued my looking Dow the accessory case and all the gears looked great. So something must have let go on the bottom end .. started to pull the the motor where it sits, got a loaner motor from a local guy to get me back to town.. time to pony up for a -50 I suppose..

Thanks for the update, I was wondering what happened. Keep us posted.

Kurt

UPDATE: well took me three days to pull the old motor off, and swap a loner motor to get the bird back to down. Everything worked out great. Luckily I have some great friends in aviation that lent hands and flights to get me and the bird back safe and sound. Couldn’t be more proud of the out west aviation community. Just got the broken motor back to town and found the culprit.... drumroll.. a C-clip holding my counter weight pin and come loose and allowed the “aft” pin to come loose.. looks like there was some carnage but only to a cylinder/piston skirt. I guess if it would have been the front pin, could be a different outcome..

Appreciate all the help trying to troubleshoot this guys. And very happy this happened on the ground. Guess the ol girl is looking out for me.

Cheers

J-

Thanks for the update, I was wondering what the latest was. I would count that one as being very lucky! It sure is nice having great friends. I bet you will be glad when she is fixed and back in the air.

Kurt

Wow, you must be living right to have that happen when it did! Congratulations on finding the problem and the solution. Could have been a LOT worse!

MTV