Kubota and Kioti injectors interchangeable?

[dbotos]

Injector 2 hard line cleaned up:



Closeup of hard line end:

 

[dbotos]

Tested injectors 2 and 3 tonight. 2 had good pop pressure (~2000 psi), but the spray was a little more "streamy" than injector 1, which was nice and misty. 3 was the worst of the bunch, initially popping at 2800 psi a few times and then popping a good bit lower than 2000 psi. The spray was very streamy and erratic with regard to shape and direction. I'm going to re-clean/re-build 2 and 3 and test again. I did come up with a good way to store the injectors upright - pinched the mouths of some steel cans and let the return barbs rest on the rim like little arms. Figured this would help keep air out of the injector and subsequently out of the fuel system when I reinstall.

 

[dbotos]

Something else I discovered yesterday:

1-1/16 = 1.0625"
27 mm ≈ 1.030"

The 1-1/16" deep well socket that I have fits just fine on the 27 mm hex of the injectors.

 

[Tx Jim]

Figured this would help keep air out of the injector and subsequently out of the fuel system when I reinstall.

I fail to see the concern of air entering injector as this same injector contained air when it was brand new as will the injector lines.

 

[dbotos]

I fail to see the concern of air entering injector as this same injector contained air when it was brand new as will the injector lines.

If you have air in a mechanical fuel injection branch, the pressure from the injection pump is wasted compressing that air instead of opening the injector. Similar to having air in a hydraulic brake or clutch system. Having the injector full of diesel is essentially pre-bleeding that portion of the branch.

 

[Tx Jim]

If you have air in a mechanical fuel injection branch, the pressure from the injection pump is wasted compressing that air instead of opening the injector. Similar to having air in a hydraulic brake or clutch system. Having the injector full of diesel is essentially pre-bleeding that portion of the branch.

My thoughts are after injector is installed in cyl head and inj line attached to injector then when inj pump forces fuel through line to injector then line is tightened then loosened the trapped air in inj will be displaced by diesel then upon tightening line nut again there will be air free fuel in injector. Back when I was a JD dealer service manager when injectors were removed from cylinder head for engine overhaul or pop(pressure/spray) testing the injectors were not held upright to keep fuel in them. Nor do I ever remember reading in a tech manual that stated that this procedure was required or necessary.

Are you implying you think new injectors designated for parts are shipped from factory with fuel in them??
Thanks,Jim

 

[dbotos]

My thoughts are after injector is installed in cyl head and inj line attached to injector then when inj pump forces fuel through line to injector then line is tightened then loosened the trapped air in inj will be displaced by diesel then upon tightening line nut again there will be air free fuel in injector. Back when I was a JD dealer service manager when injectors were removed from cylinder head for engine overhaul or pop(pressure/spray) testing the injectors were not held upright to keep fuel in them. Nor do I ever remember reading in a tech manual that stated that this procedure was required or necessary.

Are you implying you think new injectors designated for parts are shipped from factory with fuel in them??
Thanks,Jim

Jim,

Yes - loosening the hard line tube nuts on the tops of the injectors and then cranking the engine (my manual says full throttle with decomp) seems to be a common air bleeding procedure. I'm saying that if you've just tested an injector that you're going to reinstall, you might as well leave the fuel in it so there's less air to bleed out of the system later. I don't think anyone is shipping injectors with fuel in them - probably against some shipping laws. I would imagine OEMs and rebuilders drain or purge them somehow after testing.

David

 

[dadster4]

Jim,

Yes - loosening the hard line tube nuts on the tops of the injectors and then cranking the engine (my manual says full throttle with decomp) seems to be a common air bleeding procedure. I'm saying that if you've just tested an injector that you're going to reinstall, you might as well leave the fuel in it so there's less air to bleed out of the system later. I don't think anyone is shipping injectors with fuel in them - probably against some shipping laws. I would imagine OEMs and rebuilders drain or purge them somehow after testing.

David

Any new injectors (24 of them) we install from Fairbanks-Morse for our diesel generator at work, and when testing the injectors ourselves, diesel fuel is not used to test the spray pattern and pop pressure. A non-flammable oil with similar properties is used so shipping with this fluid is not an issue.

 

[dbotos]

Got injector 3 re-cleaned and rebuilt. Spray is much better now. Pop pressure was around 2100 psi, which is on the higher end of the specified range. I made sure everything was well-aligned, especially where the butt end of the nozzle needle fits into the spring plate. Here's the assembly process I used (after cleaning the parts in the ultrasonic, rinsing with clean water, and spraying healthily with WD-40 while holding in clean nitrile gloves):

1. Stack shims on top of spring.
2. Insert shim/spring stack into upper housing (orange), held right-side-up.
3. Flip over; place spring plate (green) on bottom end of spring.
4. Place spacer (gray) over that.
5. Place needle (purple) and nozzle body (darker blue) assembly on top, with butt end of needle in recess of spring plate.
6. Hold all of the above in alignment with one hand while installing lower housing (brown) over top with other hand.

 

[dbotos]

Any new injectors (24 of them) we install from Fairbanks-Morse for our diesel generator at work, and when testing the injectors ourselves, diesel fuel is not used to test the spray pattern and pop pressure. A non-flammable oil with similar properties is used so shipping with this fluid is not an issue.

Got any info on the test oil? Is it mainly the viscosity that has to match?