312-8 engine swap

[Steve B. 30]

A question for the customization guru's. I have a '78 312-8 and may have an opportunity to aquire an MV20 Kohler twin. I was wondering if I can swap this engine into my Horse. I've tried to find spec diagrams that would help with locating holes and such. Can anyone provide accurate info with regards to shaft diameters and whether or not the output shaft is located anywhere close to the same place when mounted. If not, would a custom mounting plate bring things back into alignment? I realize some electrical work will likely be in order. I can rewire the whole tractor if needs be, I've done a few motorcycles from scratch so the tractor shouldn't be a huge leap. Basically I'm wondering if this would be a fairly simple swap or might I be setting myself up for major reconstructive work?

Any help would be appreciated.

Thanks,

Steve

[TT-(Moderator) 1,145]

:WRS:

I'm guessing you mean an '87 312, and the MV20 is a vertical shaft engine, which - no matter what you do - will not work on a tractor designed for a horizontal shaft engine without extensive modifications.

[Kelly 1,030]

I have been told you can convert a vert shaft Kohler twin to a horiz. shaft but you will need a parts engine to pull the parts off, and will have to open the engine up to change the oil pickup, drill a new dip stick hole, swap intakes ect..... not a fast swap, I have not done it, but as I said was told it can be done, with all the right parts, then if you did swap it over to mount in the horiz. position you will need a mounting plate, I've been told Onan plate will work with a couple new holes drilled in it.

[Jake Kuhn 1,556]

:WRS:

[Steve B. 30]

Bugger, you are right TT. The MV20 is a vertical shaft. I am looking at an M20... (too bloody many notes on my scribble page right now). I have attached a pic of the engine in question (currently powering a home-made band-saw mill).

As to my model, it is a '78 C-121 8-speed. Again reference my messy notes page, the 312-8 is the nearest model that my local Toro dealer recognizes (the girl at the counter hadn't even heard of a Wheel Horse before I wandered in) seems these are fairly scarce in Atlantic Canada.

I did find a spec sheet for the M20, but it is a horrible scan (numbers are largely unreadable). I have attached it as well, any chance someone recognises it and has a better copy?

[TT-(Moderator) 1,145]

Oh yeah..... now you're on to something!

The M20 was actually used on a Horse, as was the M18. You could use a mounting plate for a 418-A or a 418-8 (and probably the 417-A & 8 models too), but you'll need to remove the isolation mount blocks from the frame. If you want to keep the rubber-mounted engine, the C-175 cradle should work.

I'm pretty sure you're in for some hood modifications either way.

[Steve B. 30]

Wuhoo! That is good news. According to the WH interchange charts the C-175 would be an '84ish, does that sound right? With the 418's being '87? Should be able to order the parts from my local dealer. Which would be the better way to go? Rubber mounts or no? Down the road, I'm looking at building a loader (using plans from the internet unless I can aquire one from soemwhere). I'm thinking the 20hp will provide plenty of strong for the hydraulics.

So, on to other questions. Can I expect to recycle my output pulley and PTO? Or will I need to upgrade these? According to Toro's parts site they appear to use the same Bearing Race PN#6658 as well as other components. Can't tell for sure which parts would be centermost piece on the shaft. Also, should I expect the M20's output shaft position to be close to the K301's?

Thanks for your help TT. Oh yeah, please tell me I will not be overstressing my transaxle by almost doubling the hp.

Steve

[can whlvr 993]

you should be able to order parts for you tractor with the correct model number,i use www.partstree.com and go into toro and go from there,you can use toro,s site too,with the numbers all they have to do is order them