Turning up fuel on Kubota D950


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Turning up fuel on Kubota D950

Jeremy My buddy just acquired a Kubota D950 Diesel Engine. Were gunna work on putting it in a frame for a garden tractor puller...we wanna know how can we turn up/Adj the injector pump for more power? I know alot about diesels but im not familiar with modifying that type of pump.
Jason Depending on your elevation you can shim the inj pump,. or put a turbo kit in from swaginc.com



peter need to find where hydralic filter located
Jeremy How would we go about shimming the pump and will this make more fuel pressure?

Jason It will either advance or retard your inj pump timing. There are steel shims under the inj pump that can be added.

I don't have too much experience turning up the pumps because there really isn't much of a way on the little engines.

The first thing that came to mind was the shims, because some of the generators we get are for lower altitude and we have to remove shims because they over fuel.

Tom Bower Hi jeremy,
I installed a turbo on a D722 in my B7300 a few years
ago.
First order of buisines was to get a basline naturally
aspirated.
Hooked up to the dyno and went from 15.5 h.p. at the
factory setting to 16.5 before the smoke started
to get thick. Lots of black smoke from a diesel
does "NOT" mean more power. Just means an improperly
set pump among other things. The little engine responded like most other
diesels as when the smoke "just starts is usually"
the best setting.
Then installed the turbo. I brought up the fuel slowly and got 21.1 h.p. at 7 p.s.i. boost before
the smoke came and the subsequent drop in power.
That was at 50 hrs. on a new tractor in 1998.
Now at 1500 hrs. of very hard work the little critter
runs perfect still. And the extra power was very well
worth it for my application.

To turn the pump up on the D950 which I think is
nearly identical to the 722 cc version of the "D"
engine I have, is to pull the cap off the stem
on the front of the pump, and there should be a
threaded stud with a lock nut on it. If you loosen
the lock nut and turn the stud out that will increase the travel limit of the rack inside the
pump. You only need to turn it a very small amount at a time. With your naturally aspirated
engine you may only get 1/4 turn before the smoke
comes and power starts to drop. When you get to that
point thats all there is. Aint no more till you
turbo it.
I think that little turbo I put on my little 722 cc had a turbine A.R. ratio around .44
I would like to find a turbine housing at about
.42 A.R. to bring the boost up to about 14 p.s.i.
which it should handle just fine. If not-I'll just gate
it.
Your 950 cc should really respond to an A.R. of .44 turbine and an A.R. of about .48 on the
compressor side. Those #'s are from memory. If
you need I can probably find my old notes on this.
Sounds like a kick in the butt project. I've done
the tractor pull stuff a bunch years ago and it was
a blast.
Good luck with it, tom


Jeremy Thanks alot guys, we do plan on turboing it and one more question is do we add or subtract shims to advance the timing? And what shim thickness equal 1 degree advance?

Jason Thanks for the explanation Tom
Jason I honestly can't remember,.. I will have to check one of my books tomorrow,.. but if someone else can pipe in,.. more power to them..
Tom Bower Jeremy,
Here's what I remember about the shim thing when I
put the "prune tune" on the 722.
The shims come in 3 thicknesses, 0.20mm 0.25mm 0.30
0.05mm advances or retards timming by 1/2 deg.
I can't remember which way it goes though.
A good question for Jason.

Check out the turbo on ebay. Item #180147153811
It has a compressor A.R. of .33 and a turbine A.R. of .43 It's also gated.
Thats about in the middle of a good starting point
on ur 950 cc. Theoretically you can use math to
get smack on with the specs of a turbo, but you
need to tear the engine down and put it on a flow
bench to find ur volumetric efficiency numbers
and all that stuff.
Sometimes it works out better just to spool one up and
look at those #'s and go from there. Generally a
smaller A.R. turbine is higher boost but that can
depend on wheel trim, blade rake, altitude, compressor A.R. and a lot
of other gooffy variables
Just pullin #'s out of my *&#$ hat and from past
experience doing turbos you should get around 28 h.p. from
that 950 at 12 p.s.i. or so. (or more depending on how far
you want to put the pressure on)
Let us know how it works out. tom

Tom Bower I think more shims retard and less shims advance.
jim strelow I am looking for a crankshaft for a kioti td950 3cyl diesel engine. Does anyone know if a kubota d950 crankshaft the same the look the same but the part numbers are different. I try to locate a used crak for a kioti but can not find one but can find crank for a kubota.
Phil Kicksee Does anybody know where I can find a head for a kubota d950 bg1?
Fred Micheals It looks there are a lot of Kubota heads and cranks on GrainFarmer.com
Bobby Parham Thanks for all your help. I plan on doing this swap very soon.
Vern thompson Is there different springs for governor on pump for a line shaft


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