Crankshaft question

[JimmyG]

I have an old pulling tractor that I am putting back to a working tractor. It is a 128 with the engine from a 1200 in it. It had a bad clutch failure that did a ton of carnage including tearing all the fins off the flywheel. When the clutch coupler let go the flywheel loosened up and sheared the key. It also bent up the threaded end of the crank. The threaded end appears to be screwed into the end of the crank. Could this engine have been built with a John Deere crank with an adapter in the end? Going to try and remove it tonight.
Jimmy

[J-Mech]

The later crankshafts had a bolt instead of the threaded crank. It's likely either a replacement motor, or crankshaft.

[JimmyG]

Well I did some checking and the piece is threaded into the crank. Its just threaded in there at an angle. So now I need to decide what to do with it. The fix applied to this one was not so good. I did take a look at the condition of the engine by pulling the head. Here is what I found. Bore is nice and clean and 3.400, stroke is 3.250, deck is .018 in the hole, intake valve is 1.375 with .315 lift the exhaust is 1.250 and .300 lift and it has what looks like the LP head. It looks like a pretty stout little motor with a bad crank fix.
Jimmy

[J-Mech]

Ok.... so you have a K301 bored .030" over, with a stock crank, stock cam and stock valves and the exhaust is either out of adjustment, or the lobe is wore down. I have no idea what you are talking about "the deck is .018" in the hole"... What's the point?? You still need a new crank, or fix that one. Are you sure it just isn't a bolted flywheel and the bolt got bent in the carnage??

[JimmyG]

Nope the crank was repaired using a chunk of 5/8 18 bolt. I pulled the piece out. When they drilled and tapped it it was done at an angle. When I checked the deck height the piston sets down .018 from the surface of the top of the block. The measurements just tell me what I am starting with as everything in this tractor is an unknown. The engine looks to out of a quiet line by the starter and the shields on the pto end of the engine. It has the dash and front end from a 1200 on it. My comment about it being a stout little motor is more about the over all build and construction of the Kohler. Much different than the new stuff I am used to working on. It will come apart to get a new crank and see what else may need some attention as it goes back to a working tractor. Never know what you will find with a project like this. Any suggestions on finding a good used crank?
Jimmy

[J-Mech]

Ebay or a wanted ad on this site are the best resources.

Need to decide which crank you want first.... one for an older K341 or the newer style.
With the damage done, may want to just buy a complete engine. Reading your description again, it me have been over revved.

[JimmyG]

Will see what it looks like inside. Looks like the coupler failed let the clutch assembly get picked up by the fins and it really wreaked havoc on that. When the coupler came apart that let the flywheel come loose and it sheared the key. A quick check and the crank has about .002 run out and that surprised me.
Jimmy

[J-Mech]

Originally Posted by JimmyG

Will see what it looks like inside. Looks like the coupler failed let the clutch assembly get picked up by the fins and it really wreaked havoc on that. When the coupler came apart that let the flywheel come loose and it sheared the key. A quick check and the crank has about .002 run out and that surprised me.
Jimmy

Again, if it was a puller, it was likely from overspeed.

You apparently haven't been into many of these Kohlers...... Crankshaft wear is common. It's also a commonly overlooked thing for the "do it yourselfer's" when rebuilding. They all go, "Oh, it's fine" and put it back in without grinding it.

[austin8214]

I have a good k341 crank that is ground .020 under. If you are interested.

[J-Mech]

Originally Posted by austin8214

I have a good k341 crank that is ground .020 under. If you are interested.

Same stroke, but it's weighted different.....