D850 repower

[Jonas Smith]

So on the advce of a forum member I bought a D850 locally to replace the fd up D750 in my B7100HST. It is a complete power unit that came out of a mobile light trailer from the SeaTac airport. Basicly it bolts right up, but the cooling will be a issue. The tractor uses a bigger radiator than the power unit, but a smaller fan. Also, I have to be a bit creative about plumbing the water pump on the 850 to the tractor radiator.

The problem is, the 850 water pump uses 1" radiator hose, and the tractor radiator uses 1.5" hose. The problem is solved by putting short section of 1" rubber rad hose over the inlet and outlet ports of the water pump (thereby increasing the OD of the ports), then sliding 1.5" radiator over that and clamping it all down to make the connections to the radiator. I had to make a slight modification to the lower rigid pipe the comes off the water pump but I'll get pictures to explain all that later.

I also had to swap the smaller 4 bladed fan from the tractor over to the 850 waterpump. The larger 5 bladed fan will not fit in the shroud, and the fan shroud will not swap over to the tractor radiator.

Other than that (and swapping over the oil pan and pickup tube.), it's a very straightforward changeout (so far).
I guess I'll have a few horsepower with the 850, but more importantly, I like the idea of having a waterpump, and a stand alone dyanamo.

 

[Kytim]

Yep!, great. Need PIC's.

 

[kubota kid]

Iam pretty sure all you gota do is swap the water pumps, and all other things that are different,.Same basic engine, just a different bore

kubotakid USA

 

[Rob]

yep, i did a similar project recently and its working great.
What base spec D850 are you using now? and does it use the top mounted over the inlet manifold alternator/dynamo or side mounted dynamo above the oil filter, i ask this as there are a few issue to deal with if you are swapping between the too versions, they are in my thread from a few weeks ago.

BTW, the 4 fan blade from you 7100 will work fine cooling wise on the 850, make sure that threre is a thremostat in the housing as it does make a big difference.

good luck with it, as allready said, pics are good...

rob

 

[Kytim]

Rob, I'm sure you have mentioned this somewhere but, what tractors came with the 850 powerplant? I want to try to track down the on top alt/dyno brackets.

 

[Rob]

hi, yes i am just backtracking now through my notes as i have those part number here somewhere.
It is standard fitment on mid/late production B7100's inc the hst version in the uk, but, not sure about elsewhere.
as soon as i can find the numbers you need i'll post them up.
I dont think you'll find them on that many machines as it does appear to be specific to a small group to facilitate the fitment of the top mounted alt/dynamo.

i'll update you shortly.

rob

 

[Apogee]

Good job Jonas!

Soon you will have a new toy that will be awesome!

Also looking forward to pics of the project.

Best,

Steve

 

[Jonas Smith]

Couple of pictures. Got it together and running, funny thing though, the bottom radiator hose is staying cool, while the upper hose is warm after about 1/2 hour of idling. I'm wondering it the thermostat is not opening up.

I need to figure out how to plumb in a water temp gauge, and a oil pressure gauge.

Fun little tractor to wheel around the yard!

 

[Apogee]

Excellent!

Nice trick on the hoses, I wouldn't have thought of that...

I'd just replace the thermostat and not take any chances. Certainly cheaper than a new cylinder head. Might also be worth checking the water pump impeller just to make sure it's in good shape. Radiator needs to be clean and not full of dust, weeds, etc. (Yeah I know common sense, but you'd be surprised at what I've seen...)

Another thought, did you run a hose through the radiator with the lower hose disconnected to make sure it isn't plugged? Might be worth doing so you know for sure that it flows correctly. The radiator in my Rover was plugged with calcium deposits and must have weighed 60 lbs. Pretty weird, but it also taught me a lesson because it melted a piston from overheating on the previous owner and the radiator being plugged was the root cause.

One more thing, make sure the bolts that hold the front frame of the tractor to the engine block are good and tight. If you search, you will find folks have had problems with the bolts stripping the threads from the block when using a front loader because the bolts were loose. From what I've read, when the loaders are worked hard it puts considerable stress on those bolts so they need to be tight.

Finally, do yourself a favor and change the oil in the steering box now to make sure there is no water in it. The bushing up under the steering wheel wears and it allows water to run down the steering shaft and it works its way into the box and causes problems. Better to just tackle it now so you know its status.

Out of curiosity, what is the chain driving off the front pulley or is that just a tool for turning the crank?

You will find these Kubota's, while cute, are able to do far more real work than you would think just by looking at them.

Congrats!

Steve

PS - Toss up some pics of the tractor. We enjoy seeing them no matter what they look like!

 

[Rob]

yep, thats a novel method of doing the hoses.
The water temp/oil pressure are easy, replace the oil pressure light with a pressure sender and add a t-piece to fit the pressure light back in if needbe,job done.
water, there is allready a plug, or should be, in the neck of the thermostat housing, just remove it and fit the appropiate sender (12v) method , alot of 850's have the sender allready fitted, if not you'll need to get a reducer to drop the thread size down as its a larger than standard of the shelf sender and most common sender are smaller.


good one.

rob

 

[Rob]

Rob, I'm sure you have mentioned this somewhere but, what tractors came with the 850 powerplant? I want to try to track down the on top alt/dyno brackets.

I have checked through and have the part numbers, but, as your machine is missing all the parts, and there are quite a few needed to do the mod, the cost is not cheap and it may not be a viable option for you.

if you still want to go down this route drop me an email and i'll forward on the part numbers as there are a lot involved.

thanks
rob

 

[Jonas Smith]

Out of curiosity, what is the chain driving off the front pulley or is that just a tool for turning the crank?

It connects a shaft that drives the Vickers hydraulic pump for the front end loader.

 

[Jonas Smith]

And possibly a power steering unit...

 

[Rob]

just out of interest, have you refitted the engine side cover on the exhaust side yet, my engine had the same dynamo setup as yours , on the left above the oil filter.
I did think about using the engine as it was but the dynamo stuck out and the side cover would'nt fit back on properly without really bending it out of shape.
Decided to use the improved alternator/dynamo fitted on top above the injector pump instead.

rob

 

[Jonas Smith]

Nope, I have not installed them. I'll probably just leave them off if there's a clearance issue. Although, an alternator would be nice since I have a rear mounted Warn T2500 electric winch for it. I dont know if the dynamo has the minerals to keep up with anything other than light winch use.

 

[Kytim]

Well, If you decide you don't want the bracket, etc. give me a shout will ya? I'd like to assemble the necessary parts to do mine sometime.

 

[Apogee]

Rob,

I'd love a list of the parts involved for the alternator relocation.

I think it would be great to have it in its own thread and available to everyone who is interested.

Thanks,

Steve

 

[Rob]

thanks steve, just posted a new thread with details etc, its not a great thread but i think it is about right and i am open to updates etc on it .

thanks
rob

 

[Jonas Smith]

Engine installed pictures...

Here is a picture of the clearance of the dynamo. I had to shave just a little bit off the side of the hood. I'm not using the side panels:

And just some pictures of the thing...

 

[Apogee]

Nice tractor!

I'm jealous of the wheel weights....

Cool!

Steve