Crankshaft question
 

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

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

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

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??

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

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.

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.

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

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

I have been turning wrenches for more than 40 years and drag raced for about 30. Everything I work on gets the same level of detail as one of my race engines. Some of this comes from racing and some of it comes from working for NASA for the last 37 years. Everything gets checked and it all has to be right or it's fixed or replaced. I did check the run out fully expecting the crank to be bent. I'll post what I find with pictures and measurements.
Jimmy

Pretty common for us to use them in pulling engines. Even governed ones. But we typically add a billet stock length rod.

Going to see a guy in Richmond this weekend and try and pick up most of the missing parts for the tractor and look at a crank. Will take a set of micrometers and see how it looks. Been doing some reading on the stuff that is done to the governed stock class pullers. Interesting that no one gives out cam specs. Going to run the one in my engine through the cam checker and see what it is so I can learn a little about the cam timing on these engines.
Jimmy

Jimmy, if you have a question just ask. I don't know what it is your looking for, but there isn't any need to go off and do a bunch of work if all you want it cam specs. You posted the lift on your valves and I told you you had a stock cam.

The stock cams in the K series Kohlers will vary quite a bit. They didn't adhere to a very strict set of tolerances. If it was close it went.

Stock they had about .324"-.328" lift and about 117 deg duration. I think the lobe separation is about 105 deg. Cam timing is all over the board. If you want to change the cam, (even though you said your taking out of pulling and making it a worker) I suggest going with the Kerber Gov II cam.

Was looking at the cams that are out there to see what they were doing with them for the stock governed engines just from an information and learning stand point. Looked at both stock and aftermarket cams. Vogel was very specific on the cam numbers like I am used to looking at. Lokota gave little information. Kerber give good specs but not as detailed as Vogel. The reason to look at the stock cam was to get a base line to help understand the changes from stock in the other grinds. Also looks like the cam I have is one of the ACR cams that just opens the exhaust port on the compression stroke. Would be an interesting profile to look at. I have the free run of a very well equipped race engine shop and stuff like measuring at the cam profile is easily done and it teaches me something. I feel like if I am learning something new its a good day. My methods may be a bit more work than asking the question but in the end I learned just a bit more. So please be patient as I go from motors where my 557 inch motor was a small one to less than 30.
Jimmy

there's only so many ways you can grind a stock cam casting, all they can really do is change the base circle ever so slightly and advance the opening and closing of the valves, Kerbers #3 cam he spray welds the cam before grinding. while there's gains I believe there are more gains in the valve seat angles and valves . there are several head designs you can play with on a K301 . obviously any time you change air flow you change BSFC and AFR. at some point carb work is needed , the governor weight assembly can be fine tuned and matched with proper spring tension to get a more responsive engine when load is applied . advancing ignition timing and last but not least exhaust pipe length and diameter is critical . dyno time really helps with all this.
most Kohler singles have the ACR, early 7 & 10 hp's had the 2 piece or spark advance cam .
I should also add that the 14/16 crank does work nice in the 12, if you balance the rotating assembly you rarely have to add heavy metal

I got the crank, rod and piston out tonight. Crank is standard and really looks pretty good. Took a picture to post but it was not focused very good. Rod looks like the ones you see in the rebuild kits online. Got a look at the way the ACR cam works and pretty simple little system. Looks to be on the princible as the ez start Harley stuff from S&S that I have seen. Has anyone got the compressed thickness of a stock head gasket? This engine had a .062 copper gasket in it.
Jimmy

Compressed stock head gasket is right around .060 give or take a few .001

Thanks for the info. Going to go back to the stock head gasket.
Jimmy

You'll definitely have a lot less trouble with it sealing up that way.

We used copper all the time on the race engines but the cylinders are oringed with a wire oring and the blocks have receiver groves in them. There are signs on this one of a leak.
Jimmy

Picked up a donor engine last night to hopefully get everything to build a good engine. It was a complete engine from a 1200 less the carb. Oil looked good and it turned over smoothly. Hope to have it apart and checked out by the weekend.
Jimmy