K Series Crankshaft questions

[ClassicTractorProfessor 5,356]

As some of you may remember I threw a rod through the block of my 1277 while mowing this summer. I acquired a block from a fellow member here and was gonna use it to build a new engine, but have decided to hold on to it to use for a custom project I see later on down the road  don't let the suspense of that kill y'all lol. Anyway I scored a heck of a deal on a running K241 the other day, problem is the output shaft is not only a bigger diameter but also shorter than needed for my pto. I know the stroke is different on the 241 from the 301, but is this due to the crank or a difference in rod length? My K301 crank miraculously survived the carnage that day, was curious if it could be swapped into the K241 I picked up the other day, and if so, what combination of parts do I need? Thanks in advance

[953 nut 56,338]

The boar is 3.251 on the 241 and 3.375 on the 301; stroke is 2.875 on the 241 and 3.250 on the 301. If you use the 241 piston with the crank from the 301 and a new rod for a 301 and ring set and gasket set for a 241 it should work. I am not 100 % positive, but pretty certain it will work.

Kohler Single Cylinder Engine Specs _ Torque Values and Sequences for Fasteners _ Identification & Torque Settings of Most Commonly Used Grades of Bolts (1) (1).html

This manual shows all of the numbers on engines.

Kohler_Guide_To_Engine_Rebuilding_19890900.pdf

This is loaded with great information.

 

[ClassicTractorProfessor 5,356]

That's what I though by what I read earlier was that I could use a 241 block and piston/rings with a 301 crank and rod, essentially creating a stroker K241, but wanted to verify what I was reading before I tear into this thing

Edited November 16, 2016 by Professor1990

[953 nut 56,338]

The pan on the 301 could be deeper to accommodate the slightly longer stroke too.

[ClassicTractorProfessor 5,356]

By what I can see by looking at both of them earlier I think the pans are the same depth, however I plan on using the pan that came off my tractor originally so shouldn't pose any problems there. Thanks 

[Shynon 7,474]

35 minutes ago, 953 nut said:

I am not 100 % positive, but pretty certain it will work

I'm with Richard on this one, I have not tried it yet, the only issue I see is if the skirt on the cylinder is lower the crank will hit. I would install the 301 crank in the 241 block put on the bearing plate and turn it and see if it will hit, next would be to install a piston and rod, again see if it will hit. The reason I say this is I tried a 181 crank in a 161 block and it was a no go. Let us know what you find out, I would like to know.

11 minutes ago, 953 nut said:

The pan on the 301 could be deeper to accommodate the slightly longer stroke too.

All wide base oil pans are the same depth

[953 nut 56,338]

I should have thought of this earlier, Brian Miller is the small engine guru, check out his web site to see what he has to say.

http://gardentractorpullingtips.com/index.htm

This is from Brian's site,

The Kohler K-series and Magnum engine model and serial numbers appears on a decal or metal tag that's attached or affixed to the flywheel shroud, on the carburetor side of the engine. If there's no tag or decal that originally came with the engine, or if the engine block was replaced with a replacement short block or if the flywheel shroud has been replaced, there's no way of knowing exactly what year the engine is. All you'll know is the year of the flywheel shroud itself. Decals/tags and flywheel shrouds can be swapped from one engine to another and there are no numbers or identification characteristics on the blocks themselves (except for the 10hp through 14hp engines has 9 head bolts, the 16hp has 10 head bolts and the 18hp is OHV). Therefore, the best way to find the size and model of Kohler engine is to remove the cylinder head and measure the bore and stroke. (Otherwise, they are like the small and big block Chevy V8's, there is no way of knowing for sure simply by looking at it on the outside.) Because a Kohler K241/M10 (10hp) block can be bored and stroked to a model K301/M12 (12hp), using a K301/M12 (12hp) piston, rod and crank, and a K301/M12 (12hp) block can be bored to a model K321/M14 (14hp), using a K321/M14 (14hp) piston, rod and crank. And the models K341/M16 (16hp) blocks are in a class by themselves. There is no way to convert these into a bigger (model) engine by using OEM parts from other Kohler engines.

[ClassicTractorProfessor 5,356]

1 hour ago, 953 nut said:

I should have thought of this earlier, Brian Miller is the small engine guru, check out his web site to see what he has to say.

http://gardentractorpullingtips.com/index.htm

This is from Brian's site,

The Kohler K-series and Magnum engine model and serial numbers appears on a decal or metal tag that's attached or affixed to the flywheel shroud, on the carburetor side of the engine. If there's no tag or decal that originally came with the engine, or if the engine block was replaced with a replacement short block or if the flywheel shroud has been replaced, there's no way of knowing exactly what year the engine is. All you'll know is the year of the flywheel shroud itself. Decals/tags and flywheel shrouds can be swapped from one engine to another and there are no numbers or identification characteristics on the blocks themselves (except for the 10hp through 14hp engines has 9 head bolts, the 16hp has 10 head bolts and the 18hp is OHV). Therefore, the best way to find the size and model of Kohler engine is to remove the cylinder head and measure the bore and stroke. (Otherwise, they are like the small and big block Chevy V8's, there is no way of knowing for sure simply by looking at it on the outside.) Because a Kohler K241/M10 (10hp) block can be bored and stroked to a model K301/M12 (12hp), using a K301/M12 (12hp) piston, rod and crank, and a K301/M12 (12hp) block can be bored to a model K321/M14 (14hp), using a K321/M14 (14hp) piston, rod and crank. And the models K341/M16 (16hp) blocks are in a class by themselves. There is no way to convert these into a bigger (model) engine by using OEM parts from other Kohler engines.

Yes I found his site while doing some more research. That is what I was reading and also read this farther down in his page as well 

To create a 27 CID hybrid Kohler engine model K271 (Stroker 10hp), the parts to use are:

• K241/M10 (10hp) block.
• K241/M10 (10hp) piston/rings assembly.
• K301/M12 (12hp), K321/M14 (14hp), K341/M16 (16hp) stock connecting rod, or a 5.7" billet rod with a 1.500" plain aluminum journal hole.
• K301/M12 (12hp), K321/M14 (14hp), K341/M16 (16hp) or K361 (18hp OHV) crankshaft.

I hope to be starting this build in the near future, and will be starting a rebuild thread here with plenty of  for everyone to enjoy and follow along on the build. Thank you everyone for your responses

[ClassicTractorProfessor 5,356]

Ok everyone I stand corrected...this combination will not work...a k301 rod will NOT mate up to a k241 piston, the wrist pins are different. This was brought to my attention last night, I checked my Kohler manual this morning and they are in fact different, guess I will either bore this block to a K301 as well or try and find a K241 crank

[953 nut 56,338]

51 minutes ago, Professor1990 said:

k301 rod will NOT mate up to a k241 piston, the wrist pins are different. This was brought to my attention last night, I checked my Kohler manual this morning and they are in fact different,

I see what you are talking about; missed that last night. Presuming the block measures up OK you could just have the 241 piston wrist pin hole bored out to fit the 301 wrist pin and get a new pin with the rod.     Save a few bucks that way.

[ClassicTractorProfessor 5,356]

Very true Richard, hadn't thought of doing that and in fact I read a little farther down on Brian's page and found this:

 

• The wrist pin hole in the piston will need to be enlarged to exactly .8755" for use with the 12, 14, 16hp flathead or 18hp OHV ALCOA rod's wrist pin, or the wrist pin hole in the rod can be reduced with a bronze bushing i.d. of .8594" (55/64") for use with the 10hp piston's wrist pin.

[ClassicTractorProfessor 5,356]

pulled the head off the 241 I have here just now...looked pretty clean inside...hopefully won't have to do too much machine work to get this old girl up and running again

[953 nut 56,338]

     A down and dirty method of checking the cylinder is to remove your compression ring and insert it at the top of the cylinder. Measure the end gap and see if any light is visible at the sides to indicate out of round; push the ring down the cylinder an inch using the piston to keep it square; recheck then go down another inch and so on.If the end gap is consistent and no gaps are evident around the ring the cylinder is good to go.

[ClassicTractorProfessor 5,356]

24 minutes ago, 953 nut said:

     A down and dirty method of checking the cylinder is to remove your compression ring and insert it at the top of the cylinder. Measure the end gap and see if any light is visible at the sides to indicate out of round; push the ring down the cylinder an inch using the piston to keep it square; recheck then go down another inch and so on.If the end gap is consistent and no gaps are evident around the ring the cylinder is good to go.

Thanks for the tip...I plan on disassembling this engine soon as I can come up with a place to do it...wife shot down my idea of building an engine in the back bedroom that we use for storage so have to find somewhere else to do it  sometimes I think they just don't understand