Kohler engine model differences with ending letters

[OutdoorEnvy 1,420]

Hey folks, this may be a dumb question but what is the engine difference with the lettering in the Kohler engines?  For example K301S and a K301AQS. 

 

I am on the lookout for a replacement engine and noticed a lot of WH Kohler engines have an "S" end lettering and a lot of John Deere's Kohlers have the "AQS" end lettering.  Just want to make sure I'm not missing something with bolt up compatibility for the frame and PTO shaft size, etc. 

 

thanks in advance! 

[gwest_ca-(File Mod) 10,496]

Click on the picture in the link to enlarge it

 

[953 nut 51,665]

10 hours ago, OutdoorEnvy said:

Just want to make sure I'm not missing something with bolt up compatibility for the frame and PTO shaft size, etc.

Need to be sure the engine you are considering will bolt up to your oil pan, don't know of any others that have the threaded holes in the pan for the right side.

[rmaynard 14,894]

AQS is a special oil pan. The Wheel Horse models with a cradle-mounted engine, (i.e. C-121, C-125) used a K301AS. The pan was narrow and deep to fit inside the cradle.

[OutdoorEnvy 1,420]

1 hour ago, rmaynard said:

AQS is a special oil pan. The Wheel Horse models with a cradle-mounted engine, (i.e. C-121, C-125) used a K301AS. The pan was narrow and deep to fit inside the cradle.

 

So would an A oil pan fit a regular wheel horse frame?  The engine that came off my C-100 is a K241s.  And if a A oil pan won't bolt up to the frame would be bolt on a S engine and not cause issues?  Basically needing to know if I need to avoid A engines and stick with only an S model. 

[rmaynard 14,894]

Avoid the A. Stick with the S. An A engine cannot easily be adapted to your C-100. The K241S or K301S have two bolts that go down through the mounting flange and bolt to the frame, and two bolts come up through the frame an into two threaded holes in the bottom of the oil pan.

[OutdoorEnvy 1,420]

43 minutes ago, rmaynard said:

Avoid the A. Stick with the S. An A engine cannot easily be adapted to your C-100. The K241S or K301S have two bolts that go down through the mounting flange and bolt to the frame, and two bolts come up through the frame an into two threaded holes in the bottom of the oil pan.

 

Yeah I found out about the two underneath hidden bolts when I removed the K241s.  Thought at first glance it was only mounted with the two you can see from the top.  That stinks though that the oil pans aren't interchangeable then between the A and S blocks.  Well good to know... I was eyeing a couple JD's with AQS engines 

[953 nut 51,665]

This thread will show the difference between the two.

 

[OutdoorEnvy 1,420]

22 minutes ago, 953 nut said:

This thread will show the difference between the two.

 

 

Superb thread!  Thank you! 

[kpinnc 10,718]

I'm gonna be that guy...

 

If you find a "non AQS" block with the bolt tabs on the sides and the deep oil pan, they are very easy to modify for use on a Wheel Horse. The two threaded holes in the pan on the PTO side can be drilled from the top with a smaller bit first, like 3/32 (the factory holes have the chamfer from the bit in the bottom, so a smaller bit will center nicely), you can then size the holes by drilling up from the bottom to the existing threads with the reccomended bit size for the thread. Then simply tap from the top down, following the original threads all the way through. This will not cause any leaks because the pan casting has bosses all the way through. The style in the pic is on a Gravely, and is what you're looking for.

 

I've done this several times with pans from a Gravely and a Ford LGT.

 

As has already been said, you do have to avoid the JD style engines. Not only are the oil pans different, they also bolt to the block differently. The piston rod endcap is also different, and has a short dipper for use on shallow pans. 

Edited August 28, 2021 by kpinnc

[953 nut 51,665]

Jay @JPWH made his own mount for the small pan engine.