Couple new engine to bobcat

[lmoffitt@bellsouth.net]

Hello, by introduction. I am seventy five years retired family doctor who needed something to do in my retirement so like a fool, happened to see a bobcat seven fourty three cheap. I just thought it would be a neat project to rebuild it since someone had stolen the engine. Picked up a neat two k hour three cylinder deutz air cooled fifty horse engine for it. Yup, its been sitting for a year because I cant decide how I am going to hook the engine directly to the pump. When stolen, at the pump is left with a spline. The spline is inch and threequarters with twenty teeth. I was thinking I could go to the junk yard, find a matching end of a drive shaft where the universal joins the splined differential. However I dont know how to find out which junked car came with an inch and three quarter spline twenty tooth so I can saw off about four inches of the driveshaft . Now taking the sawed off end , make a stub shaft and weld the stub shaft to a round piece I can bolt to the flywheel of the deutz. If anyone has done this or replaced a standard bobcat engine with another engine and needed a coupling to go from flywheel to hydraulic pump spline, I would love to hear from them.
I have the following equipment in shop, tig,plasma, twelve inch swing lathe.
I could be barking up the wrong tree, anyone help , new Ideas would be appreciated. lloyd moffitt md lmoffitt@bellsouth.net

 

[Muhammad]

Hi Lloyd,

Welcome to TBN, and thanks for the introduction. I have moved your thread to the parts/repairs section. You should find a lot of good info here. :thumbsup:

 

[RPW]

From what I've gathered about Skid Steers they're not very complicated. The plumbing looks like a night mare but when broken down it's not to bad. I'm new in the SS area also but from what I've discovered so far is that the part you need would be best purchased from a reputable dealer. An experienced mechanic might be able to find a junk yard find and make it work but in your case you might be better off going to the dealer. BTW make sure you take the model of the SS, the serial number and the model of the new engine so they can match up the correct part. My local dealer has been very helpful in my project. I picked up a 742 (I believe) from an auction for under $2k. No wiring, leaked fuel, looked like it sat in a pit of grease and dirt and missing or rednecked alot of things. To date I've invested about $250.00 and now it's much cleaner, runs great and I have a basic wiring harness installed.

Good luck with your project.

 

[banjodunn]

G'day if it is 1 3/4" 20 spline then you should be able to get a pto coupling to go straight on as this is the size used on the newer high hp units this should make it easy to couple to the duetz. If your local tractor parts shop can't help then check out the pto coupling section on the bare co site and you should find it . Good luck with it and keep us informed of your progress and remember we like photos :thumbsup::thumbsup:
PS And welcome to TBN


Jon

 

[AlanB]

Man, if you want a project just to have a project I imagine you could sort through that, but 743's are pretty popular and the engines are pretty readilly available rebuilt at a fairly reasonable price.

Just my opinion, but would not be worth the effort, and when you are done it will still be an odd duck.

Now if you feel like pulling the hydro cooler out of a 743 and putting one in, I just happen to know where one is sitting right behind my shop that needs it done

Good luck, the only good advice I have if you go the way you are talking is find a good shop that fools with driveshafts a bunch (transmission shops in your area should know who to point you too) and they will be able to get you the stuff you need new. I would not fool with trying to find the stuff used myself, it just is not that expensive to be worth the hassle.

 

[Farmerford]

lmoffitt:

Baum Hydraulics (on the net) has a full range of pto yokes, couplings, etc., and I recall seeing some 1 3/4 x 20 spline stuff there a few months ago when I was looking for some rare splined couplings for an old mower. Their catalog is a pain to use, but I have always found it worth the effort.

Sounds like an interesting project, if you have the time and if your hearing is already gone; if not that Deutz will wipe out what little you have left in short order. Several years ago I rented a Ditch Witch trencher with one of those and I haven't heard a word since!

 

[lmalcomb]

I have a friend who has a Gehl skid steer with a deutz engine in it. As i understand it, it came from the factory with that engine.

 

[brokenot]

Finding a coupler that will work should be fairly easy. Most of the equipment manufacturers use hydrostatic pumps from common manufacturers, so there isn't any "Bobcat-specific" pump. A coupling with the correct spline count and diameter should be easy to find or fabricate. (The couplings on 743s are a simple u-joint between the engine and pump.)

What may be a bit harder to sort out, is that on the 743 Bobcat, the original engine flywheel has large fins cast onto it to provide the airflow over the oil cooler. Coupling up an engine should be pretty straightforward, but you'll have to fab up some type of blower to provide adequate airflow.

It's been years since I had a 743 engine pulled out, but if I remember correctly, those fins were about 2 to 2 1/2 inches tall. You can imagine the amount of airflow they provide.....