Kubota BX2670 Engine Swap

skrillac

New member

Equipment
Kubota D1105-T
Sep 13, 2022
8
1
3
Dallas, TX
I recently started an engine swap of a BX2670 that had a hole in its block. Stock those tractors come with a D1005. I had a D905 on my garage floor for awhile that had originally come out of a light tower and figured it'd be a suitable replacement. Prior to swapping any parts around I was able to start the D905 fairly easily, so I started this whole process. However, now that the engine is back in the tractor I'm having difficulty starting it.

The major different parts that needed to be swapped between the engines seemed to be the governor assembly, oil pan / pickup, and gear cover. Those have all been swapped over. The D905 has sat around for a while, even before sitting in my garage. So I also swapped over things like injectors and injector lines, after cleaning in an ultrasonic cleaner, as the original parts in the D905 were rusty. The injection pump I've installed is a pump I cleaned and set aside awhile ago. I've also used the block along with said injection pump and injectors to test their spray pattern. So suffice to say, I'm fairly certain its not an issue with injection pump or injectors. Or really the entire fuel delivery system, aside from timing. I have videos of all of these tests if needed to provide further context if necessary.

I've also checked compression cold, since I can't start it. Before doing so I took the head off to inspect valve seats and cylinders before checking injector spray pattern. I can still see cross-hatching in the cylinders and the valves look good. After putting the head back on I got compression readings for each cylinder. Cylinder #1 440psi . Cylinder #2 420psi . Cylinder #3 400psi . Those readings are well above the minimum 327 the wsm mentions. So I'm pretty sure its not a compression problem.

That pretty much just leaves timing, right? I haven't changed the metal shims under the injection pump. I've also verified valve lash by the WSM, set to .006" . I've uploaded a video to youtube of trying to start it.

Anyone have any pointers?
 

skrillac

New member

Equipment
Kubota D1105-T
Sep 13, 2022
8
1
3
Dallas, TX
I've also included pictures of myself checking engine timing (gears). As well as pictures of injector spray pattern and the lobes on the fuel cam.


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North Idaho Wolfman

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L3450DT-GST, Woods FEL, B7100 HSD, FEL, 60" SB, 743 Bobcat with V2203, and more
Jun 9, 2013
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Sandpoint, ID
You should have used all the shims that were under the injection pump on the D905.
The pumps don't change the timing shim count the block does.
Have you gotten it to start at all?
Did you get the glow plugs hooked up properly?
Have you bled the fuel system to the injectors.
 

skrillac

New member

Equipment
Kubota D1105-T
Sep 13, 2022
8
1
3
Dallas, TX
You should have used all the shims that were under the injection pump on the D905.
The pumps don't change the timing shim count the block does.
Have you gotten it to start at all?
Did you get the glow plugs hooked up properly?
Have you bled the fuel system to the injectors.


The original injection pump shims were used.
I got the engine to start originally before swapping things. I have not been able to start it since.
I have tested all of the glow plugs and they all function properly.
I also did bleed the fuel system by turning the engine over with the starter until diesel was coming out all injection pipes, then tightening the lines down to the injectors.

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North Idaho Wolfman

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Staff member
Lifetime Member

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L3450DT-GST, Woods FEL, B7100 HSD, FEL, 60" SB, 743 Bobcat with V2203, and more
Jun 9, 2013
29,556
5,804
113
Sandpoint, ID
Sounds like it's possible that you installed the governor wrong or the injection pump wrong into the governor linkage.
 

skrillac

New member

Equipment
Kubota D1105-T
Sep 13, 2022
8
1
3
Dallas, TX
Sounds like it's possible that you installed the governor wrong or the injection pump wrong into the governor linkage.
I don't think the injection pump is installed wrong. I did swap the two-lever governor assembly for the 3-lever governor assembly. Thinking about swapping that back, but the WSM talks about how the 2-lever type is for the BG series (1800rpm). And I don't really think the governor assembly would affect starting, not unless the start spring was broken. Here's what things look like now. The start spring pulls the fuel rack all the way forward. The fuel shutoff lever moves it all the way closed. I've simulated the governor flyweights actuating the governor assembly, moving that fuel rack back. When that happens while I pull the governor spring (big spring), the fuel rack moves forward a bit. So the governor and throttle work.

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I've attached pictures of both governor assemblies before dismantling

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North Idaho Wolfman

Moderator
Staff member
Lifetime Member

Equipment
L3450DT-GST, Woods FEL, B7100 HSD, FEL, 60" SB, 743 Bobcat with V2203, and more
Jun 9, 2013
29,556
5,804
113
Sandpoint, ID
So you removed the governor from the old fuel cam?
 

skrillac

New member

Equipment
Kubota D1105-T
Sep 13, 2022
8
1
3
Dallas, TX
So you removed the governor from the old fuel cam?
Following the naming convention in the photos above, I took the governor assembly from the junk block and put it into the good block. The good block is a BG type, so it had the 2-fork governor assembly stock. From what I've read about it, those are useful in fixed-rpm applications (1800rpm). Originally the junk block had a 3-fork assembly. So I swapped that into the good block, as I figured I'd need that assembly now considering the good block would no longer be running at a fixed rpm. I never swapped fuel cams, or any cams for that matter. Never even pulled cams, gears, or the governor shaft out of any block. Each block has the ones it came with originally.
 

skrillac

New member

Equipment
Kubota D1105-T
Sep 13, 2022
8
1
3
Dallas, TX
So you removed the governor from the old fuel cam?

After checking the valve clearances and compression again, I noticed compression was alot lower than when I measured it last week. I took the glow plugs out previously to set valve clearances (according to WSM) and poured some oil into each cylinder with a syringe. I noticed compression immediately improved while turning the engine over with the glow plugs out. I then put the glow plugs back in, cycled them for 10-15 seconds, and started the engine. It ran for about 5 seconds then died. This definitely confirms a fuel system issue in my opinion. I'm gonna continue trying to start it tomorrow when the battery charges up again.