Kubota and Kioti injectors interchangeable?

[dbotos]

Looking at injectors for a '91 Kioti LB1914 with a 3-cyl 0.9-L TD950 diesel engine. Came across injectors for Kubota that look incredibly similar. Here's what I know about the Kioti injectors:

hex sizes from top to bottom: 19, 24, and 27 mm
marked with number: 2170
bottom thread size: M24x2
opening pressure: 1990.8 to 2133.0 psi
shim ratio: 0.1 mm (0.004") more shim = 142.2 psi more pressure

Here are my injectors after cleaning up the outsides:



Here's one of the eBay listings for a Kubota injector:

15221 53 New Fuel Injector Made to Fit Kubota Tractor Models L175 L225 | eBay

 

[dbotos]

Forgot another measurement...

topmost thread (for high pressure line fitting): M12x1.5

I took the frontmost injector apart to clean/check the inside and discovered that the top portion of the lowermost housing is ovaled (inside measures about 0.900" one way, 0.850" the other way). I had unscrewed things all the way, but the halves didn't seem to want to come apart. I believe that mating thread is M22 (0.866"), which explains why it would be digging into the sides that are 0.850" apart. I'm going to see if I can squeeze it back round in the vise or arbor press. Of course, it may have questionable reliability afterwards (best case: just the top portion is messed up and can be fixed without affecting the internal threads down lower). Probably more confidence-inspiring would be if I could replace that lower housing portion (anyone know who might sell rebuild parts for an injector like this?) or just get a whole new injector (would be nice to get one of those Kubota ones for ~$50 if they're interchangeable).

 

[dbotos]

Squeezed on the hex with a big Wilton vise lined with aluminum soft jaws and it now measures ~0.875" inside in both directions. It looks like they didn't get the hex on the centerline of the part when this one was machined, so a portion of the wall is thinner and could have distorted when wrenched.

 

[dbotos]

Took the nozzle out of the lower housing (used pieces of wood to protect things in the arbor press). It has DN12SD12 marked on it, which appears to be a fairly common nozzle. Hand-pump tester should be arriving in time to mess with this weekend.

 

[dbotos]

Here's a page linking the DN12SD12 nozzle to Kubota injectors. Again, the rest of the injector body looks pretty much like the ones I pulled out of my Kioti.

How to – Rebuild Kubota D85 injectors | FotiFixes.com – A Journal of my fixes

 

[dbotos]

Injector tester that I bought arrived with a bad pressure gauge. Fortunately, I was able to get a refund. Now I need to get a replacement.

 

[Threepoint]

Interesting. I'll look forward to your conclusions. With so much reverse engineering these days, as well as outsourcing by major equipment brands to some of the same Asian vendors, I wouldn't be surprised to see close similarities. But is your investigation more than a curiosity? :scratchchin: For something as critical as an injector, wouldn't we always specify OEM to minimize risk?

 

[dbotos]

Kioti and Kubota had a partnership at one point, which makes the notion of some common parts believable even after parting ways:

The 登ther Orange Tractor. Kioti. | OrangeTractorTalks

I'm thinking that both companies probably just buy the injectors from some other specialty company that makes them. My hope was to confirm that the injectors are the same and thus have a cheaper source than buying the Kioti part number from a dealer.

 

[art]

They did have a partnership in the seventies and kioti has followed them with Kubota's designs ever since. It is amazing how many parts are exact fits although often just a small change depending on the parts but even engines can be changed as the copy is that close.

 

[dbotos]

Got a working injector tester and mounted it to a piece of thick pallet slat with 5/16-18 tee nuts and bolts. I bent the adapter line 90 degrees with a tubing bender so the injector would sit vertical. Wasn't sure what the return barbs on the injector would do so I stuck some aquarium tubing over them. Injector 1 sprayed right around 2000 psi. Spray looked good and no dribbling. I'm plastic bead blasting the hard lines that go from the injection pump to the injectors. They look much better without all the gloppy paint on them. Plus, less chance of chipping/flaking paint getting in the connections. Speaking of which, does anyone know what standard those connections are? I found a few vague pages online about the machines that form the ends on the 6 mm OD x 2 mm ID tubing, but couldn't find a definitive answer as to what style they are.