Repowering a D

[wheeledhorseman 574]

It's a long shot I know but I've sent an email as it's worth a try. Will let you know.

[tommyg 152]

Decided to take the "plunge" and invest in a replacement Kohler Command Pro for the D180. My engine repair shop guy did some measurements and determined that it would indeed fit with a few modifications. He's had a 25hp Command Pro sitting on the shop floor with maybe 100 hours on it if that. He fired it up for me yesterday and that thing sounds like a dragster at idle. Almost a little scary. I'll need to raise the engine up so it aligns with the hydro pump. We've already connected the aluminum/rubber coupler. Bolts right up. Except I'm going to need to add some spacers so that it fully engages with the splines on the pump. The one sticking point was with the crankshaft. The  K482 was a 1 1/8" pto. This engine is 1 7/16". Pretty beefy! The machine shop is able to hone the inside of the existing clutch plate piece saying there is plenty of material to enlarge it and cut a new keyway. So I'm proceeding in that direction currently. Will post some photos of the project as I go along, but I'm getting pretty excited to be an early adopter of this engine into the d series!

[tommyg 152]

One more update... we decided to NOT hone the inside of the existing clutch housing fearing that should the housing something with the mechanism go south, I'd be hard pressed to find a replacement down the road and even that one would have to be honed to fit as well. Instead, we had a machinist turn the crank to the original 1 1/8". Picking it up tomorrow. Looking forward to diving into this project!

[wheeledhorseman 574]

Sounds good - please try and get some photos to post!

I've been waiting on a reply from the Kohler guy over here on the con-rods as he's away on holiday till next week but that line of enquiry is obsolete now. I'll still have a chat to him though about what the score is re parts for the K twins.

[tommyg 152]

Just set it in for s & g's. Initial observations look promising. It will definitely have to be raised up a good 2.5". The long PTO shaft was necessary (about 4.5") since the overall width of the engine is narrower than my original K482. Big weight difference with the aluminum block vs cast iron. Probably 50 lbs! Might make turning this beast easier. The coupler will need spacers to bring it out far enough to mate with the hydro pump. Suggestions welcome. The hood fits with room to spare, but the engine is not raised up to its final position  yet. Exhaust ports look like they'll be fairly easy to adapt. The clutch control linkage from the lever will definitely need to be modified. Might even need to extend the control arm to raise it up high enough to clear the shrouds. Anyway, I'm pretty excited and I think this is going to work. More as I progress!

[wheeledhorseman 574]

Seems strange looking at a D with a different Kohler engine in it but I have to say it looks great. There's bound to be a few challenges along the way but overcoming them is part of the reward of doing this sort of stuff.

Getting back to the official Kohler nla status of con-rods for the old engine I did hear from the small engine parts specialist over here when he returned from holiday. I didn't get a chance to chat to him over the phone as he emailed me but guess what, he has the following still on the shelf.

1 x A-277130  Con Rod STD   £69-64

4 x A-277130  Con Rod -10    £69-64

Less 10% (possibly because they're old stock)

So my suspicions were correct that for a time at least there will be these obsolete parts on shelves somewhere round the world.

I haven't asked about con-rods for a 20HP yet, but I will, as despite being pricey it might be worth me getting a pair to have in stock.

Andy

[tommyg 152]

Andy, I don't blame you for getting them while you can! I'm still confident I made the right choice going this direction. I'm certain I would have had $1000 into a rebuild. Right now I have that much into this engine with an extra 7 HP to boot. And parts that will be available for a long time to come. I've successfully (after 3 design changes) fabricated a base for the new engine that lines up perfectly with the hydro pump. Just a couple more tweaks. After carefully positioning the engine  based on the PTO location of the old engine, I've determined that the new Command Pro will be 1 1/2" short of reaching the pump. That's with the long 4.5" shaft in place. I considered using spacers to fill the gap along with some longer bolts into the flywheel. But since the coupler holes don't exactly line up with the holes on the flywheel, I would have had had to distort the rubber on the coupler to get the bolts in place. Didn't like that idea. So, I went to a machine shop, and they are fabricating for me out of steel a 1 1/2" spacer with holes drilled to match the holes in the flywheel. Then, they're going to drill and tap holes to accept the 1/4" bolts that would have normally attached the coupler directly to the flywheel on the K482. I'll post some pics next week when I get the part and get it installed.

Eyeballing the rest of the project, the one thing I have not yet figured out is how to attach a throttle cable. The existing used a rod to change the throttle speed. I'm going to need to use a cable. Thought of looking for another choke cable and reversing the position and using a cable to control the new engine. Not sure yet. Ideas appreciated.

[refracman 167]

I was wondering, I have 3 engines that need the PTO end of the crank turned down.
Was you machine shop able to turn down the crank while still installed in the engine? 
   If they could be done while still installed it would be worth the drive as I can't find a shop around here to do it.

[tommyg 152]

I was wondering, I have 3 engines that need the PTO end of the crank turned down.
Was you machine shop able to turn down the crank while still installed in the engine? 
   If they could be done while still installed it would be worth the drive as I can't find a shop around here to do it.

Believe it or not, he did! Just removed the plugs. I can message you his contact information and you guys can work out the details. He's in Petersburg, OH, just on the PA border.

[refracman 167]

If you would please!! Thanks!

  

[Don1977 604]

I sure wish you would have got pictures of turning the crank shaft. I would have like to see that. Did you have the flywheel adapter installed to chuck on to?

 

[tommyg 152]

I sure wish you would have got pictures of turning the crank shaft. I would have like to see that. Did you have the flywheel adapter installed to chuck on to?

 

Yeah, I would have like to have seen that as well. The flywheel adapter is being made totally separate. Hope to have that ready by Wed. Kohler makes an aluminum flywheel adapter that I was hoping would work, but it was way to long and the holes just didn't line up. So I had to go this route. I think in the end, it will be better than trying to force something to fit.

[shallowwatersailor 3,213]

I've been reading along with interest. Something you might consider is taking the shrouds off to check how dirty the heads are. I have two 5xi with this engine and Kohler recommends cleaning the heads every 100 hours. Kohler also has an access panel kit to get at the heads without removing the shroud that you might consider installing.

[tommyg 152]

Making progress on the retrofit. I've completed the base for the new engine. Since the new Command is physically shorter than the original K, I had a local machine shop make me a spacer of sorts with four holes drilled to match the location of the holes on the flywheel. This spacer added 1 1/2" to the overall dimension. Then, I had them drill and tap two more holes so I could bolt on the stock rubber coupler that permits connection to the hydropump. My engine base was a little shy of lining up perfectly, but adding a 1/16' spacer washer under it made up the difference. Once I got it bolted in place, I went to work on making the stock mufflers fit. Took a little head scratching, But really, it was just a matter of measuring the distance I needed from the stub-outs, then cutting and re-threading them so that everything lined up. It's a pretty simple design. This weekend, I'm hoping to finish up the wiring to the engine from the ignition switch and get this thing fired up. Getting kid of pumped! I think it looks really good!




















 

 

Edited August 28, 2015 by tommyg

[Don1977 604]

Looking good, I think you'll like how much smoother It will run and there is no shortage of power either.

[pfrederi 17,739]

Great Work!!!

[bmsgaffer 2,043]

I hope you are taking very detailed noted on all this. I am sure there will be quite a few D owners tired of sourcing parts for those old K's that will be after you for info!

[tommyg 152]

Well, it took a little time, but I pretty much have the re-power job complete for those of you interested. Here are some pics of the finished product and notes on what I did to get everything to work. I must say that it's not as hard as it might seem. Just some head scratching and a desire to make it as clean an install as possible. I can't stand cut rate options, so maybe I spent a little more $$ than someone else or time making it just right. But I will say that I'm pretty proud of the result. Cut the grass  yesterday and plowed through 12" high grass with a 60" deck with hardly whimper from the 25 horse command. Let me know what you guys think! I have a couple more "tweaks" to accomplish, like re-configuring the oil drain tube to make oil changes convenient. And for those contemplating the switch, rest assured, it's
possible!


With the base in place, the engine was ready to mount. After 3 prototypes, I wound up with this design. It consists of 1" square stock with 1/4" X 2" stock welded together. Had to add a 1/16" washer under the engine to make sure the coupler lined up perfectly with the hydropump.



I had to carefully measure the distance between where the PTO needed to be and the coupler to determine the final resting place for the engine. The dimension of the part I had machined to attach to the flywheel also depended on this. I placed the old engine in and took the necessary measurements. Had the crankshaft been a different size, I would have had to change the dimension of the spacer at the flywheel end. Looking back, I'm not sure a shorter crank would have worked.



After getting the engine positioned, the next challenge was the pivot point for the clutch arm. Fabbed this "L" from 7/16" round stock and threaded one end to mate with the threaded hole on the engine block. I tried using "all thread" for the prototype because I could not locate any 7/16" stock. But I didn't like the way it ended up. Looked a little harder and found some at Tractor Supply. Welded a washer on the end to act as a stop, and drilled a hole for the cotter pin to make sure the arm stayed put.



Next, the arm itself was too short. The original K series with its horizontally opposed cylinders had a lower profile above the cylinders compared to the V Twin design of the Command. That meant adding a little extension on to the end of the arm. I was a little concerned that the extra length would compromise the amount of pressure the clutch would provide when engaged, but it proved to be a non issue.



The connecting rod from the PTO control from the driver's seat had to be lengthened and reshaped. The original straight rod would not clear the valve covers of the V-Twin design. I put the first bend nearest the control lever, then picked up some 1/2' round stock and threaded one end to fit into the adjustment "nut". Made another bend or two to that piece to end up with what you see here. It's still not the way I'd like it because it hits the air filter housing when engaged, but I spent so much time on getting it to this point, I'll save that project for another day. Spent an inordinate amount of time bending, re-bending and adjusting that dang thing to make sure there was enough pressure on the clutch pressure plate, but not so much that it didn't disengage.



Cable connections ended up being pretty straight forward. I picked up a couple "Arnold" universal mower throttle cables, discarded the cheap plastic lever that came with it and modified the length to fit. Both the choke and throttle don't have the same "throw" as the original. Full on with the choke and full throttle and idle require much less distance. Just have to live with that. Found a happy medium and need to learn the new touch.



The last piece of the puzzle to figure out was how to attach that little PTO brake. Using that same 7/16" all thread, I welded a piece of scrap bar stock to the original L shaped bracket that held the brake. Used a nut as an adjustment so that I could position the brake exactly where needed. Then, used the original adjustment means for exact positioning against the pulley. Had to make sure this piece ended up under the pulley so as not to interfere with the belt for the blower this winter.



Here's what I ended up with! Would I do anything different? I don't know. The electric clutch option is still out there. But I really had no clue how it would attach to the PTO and finding a dual pulley arrangement was difficult. It also would have added at least a couple hundred bucks to the total. Out the door, I've got about $1200 invested. Yes, I know, that's what I paid for the tractor. Who cares. Those are the things you try not to think of. Engine was $800. Used, but low hours. Maybe 100. Machining the extension to the flywheel and labor was another $160. Turning the crankshaft from 1 7/16" to 1 1/8" was $200. Then just some miscellaneous supplies. The one thing I have to get used to is the lack of "jowls" the tractor seems to have compared to the old horizontal cylinders of the K. I kind of miss that look.

Hope this helps someone else facing the same decision!





 

 

Edited September 7, 2015 by tommyg
removed picture

[DennisThornton 4,769]

Thank you so much for sharing this with pictures!  A "D" is on my "Bucket List"!  I have struggled many times when I tried to reinvent the wheel.  It's made me skittish!  Seems there is always some "I never thought of that!" and sometimes several of them for me!  Make me nervous sometimes to be "outside of the box".  You made that leap and congrats!  Seems you landed well!  I read your comments, but I will still ask for the sake of the rest of us, some of us skittish.  More second thoughts?  What would the overhaul/rebuild cost?  Or did I miss something and that was not an option?  Either way, an exciting journey and thanks for the ride!  You should be proud of what you did but I'm just curious what you think in your quieter moments...

[tommyg 152]

Dennis, I made the decision after doing some digging for parts. They're just not to be found. I needed undersized rods and oversized pistons. The tractor is not for show. I use it constantly. So I didn't have to luxury of time to wait and hope that the parts would show up. If and when they did, I would not have expected a rebuild to cost any less than $1000.

I suppose my biggest disappointment is that the tractor isn't original any more. I tried hard to replace parts with parts that were designed for it. But after 40 years, you just have to make some decisions. I was at the local county fair this weekend and they had a couple Wheelhorse tractors on display. I thought, mine could have easily been a candidate and would have really shined in that display. But with a non original engine, I'm not sure it is any more. I suppose a lot of us need to make decisions on replacing parts like knees and hips at some point. Still doesn't change who we are though, I guess.

So that's your answer. I think the decision would be based on whether the tractor is for your collection and for show, or regular use as intended. Mine was the latter and I'd do it again. Learned a lot and hope that others can take something away.

[chrisog 2]

Nice project and great documentation of your effort, ...thanks for sharing!  

[cleat 5,957]

Well, I go to car shows all the time and engines get changed out a lot. It's common for an old Ford to have a Chev engine.

Therefor I would not worry about your engine change and go ahead and show it off.

Cleat

[DennisThornton 4,769]

tommyg I understand and agree.  Tough choice, but I think you did fine!  Thanks for taking the time to document and share!

[elcamino/wheelhorse 9,297]

All I can say is WOW. You did great work.

[pacer 3,169]

What a great thread!! plenty of pictures, lot of description/details and. oh yeah --- lots of pictures

Thanks for taking the time to document it so well...

Now we just need some one to document a Predator into a "Big D"