Bobcat 730 VH4D to Isuzu Diesel

bobcat 730 · Feb 23, 2011

I am currently repowering a bobcat 730 with an Isuzu Diesel from a thermo king reefer. Everything is going pretty well so far. I've got the old Wisconsin engine removed and starting cleaning all the years and years of gunk from the engine compartment. The biggest road block that I see so far is connecting the new engine to the hydraulic pump. The VH4D has a tapered shaft and the new Isuzu has a "coupling plate" (don't know what to call it) that bolts to the engine and the shaft from the old compressor attached to the "coupling plate" I think I have an idea how to address this problem but I want to see if you guys have any ideas first. I've got some pictures that I'll try to post to clear up the engine connection issues. I'm open to all suggestions, info, tips, and helpful comments so any help will be greatly appreciated.

bobcat 730 · Feb 23, 2011

Here's a picture of the machine the day I brought it home. Hopefully the picture will work. http://i1131.photobucket.com/albums/m546/scholzb/newtoy010.jpg?t=1298495204

bobcat 730 · Feb 23, 2011

bobcat 730 said:
Here's a picture of the machine the day I brought it home. Hopefully the picture will work. http://i1131.photobucket.com/albums/m546/scholzb/newtoy010.jpg?t=1298495204

So my picture didn't work. Any Helpful tips on posting pictures will be much appreciated.

Tazza · Feb 23, 2011

bobcat 730 said:
So my picture didn't work. Any Helpful tips on posting pictures will be much appreciated.

Does it have u-joints on this shaft?
The newer designs had a plate that bolted to the fly wheel with two u-joints to the coupler to the pump. If yours has this, i would have welded a plate to the shaft to bolt to the fly wheel. As long as you then spin it in a lathe and face it so its still running true.
Hopefully that makes some sort of sense.
Piccie is fixed.

bobcat 730 · Feb 23, 2011

Tazza said:
Does it have u-joints on this shaft?
The newer designs had a plate that bolted to the fly wheel with two u-joints to the coupler to the pump. If yours has this, i would have welded a plate to the shaft to bolt to the fly wheel. As long as you then spin it in a lathe and face it so its still running true.
Hopefully that makes some sort of sense.
Piccie is fixed.

It has a double u-joint shaft. That is what I was thinking about welding the shaft to a plate to bolt to the engine. I'll get some better pictures up this weekend to illustrate what I'm thinking.

Got the old girl in the garage

VH4D out of machine

lots and lots of gunk

more gunk
Sorry about the quality of these pictures there from my phone. I'll get some better pictures this weekend with my camera.

Tazza · Feb 24, 2011

bobcat 730 said:
It has a double u-joint shaft. That is what I was thinking about welding the shaft to a plate to bolt to the engine. I'll get some better pictures up this weekend to illustrate what I'm thinking.

Got the old girl in the garage

VH4D out of machine

lots and lots of gunk

more gunk
Sorry about the quality of these pictures there from my phone. I'll get some better pictures this weekend with my camera.

The quality is just fine.
The other issue you may have is the fan for the blower, you need something to run air through the oil cooler and radiator for the new engine if liquid cooled.

bobcat 730 · Feb 24, 2011

Tazza said:
The quality is just fine.
The other issue you may have is the fan for the blower, you need something to run air through the oil cooler and radiator for the new engine if liquid cooled.

The fan/blower for the oil cooler is actually attached to the shaft that connects the engine to the hydraulic pump so I should be able to re-use that. In the picture of the old engine you can see part of the fan and the fan shroud is in the engine compartment so hopefully that can be adapted and re-used. The new motor is liquid cooled so I'm going to need to do something to cool that. I've been looking at radiator/electric fan units on Ebay and I'm thinking that's probably my best bet.
I've been looking for some pictures of the engine compartment of a 732. I believe that it's basically the same machine as the 730 but it has a liquid cooled ford engine. Just wondering the location of the radiator and how air is moved through it on that machine. So if anyone has machine similar to my 730 and is willing to share some pictures of the engine compartment / radiator location I would greatly appreciate it.
Thanks Tazza for fixing that picture for me. I was trying to use google chrome and it won't let me post pictures.

Thanks for the input and ideas please keep them coming.

Tazza · Feb 24, 2011

bobcat 730 said:
The fan/blower for the oil cooler is actually attached to the shaft that connects the engine to the hydraulic pump so I should be able to re-use that. In the picture of the old engine you can see part of the fan and the fan shroud is in the engine compartment so hopefully that can be adapted and re-used. The new motor is liquid cooled so I'm going to need to do something to cool that. I've been looking at radiator/electric fan units on Ebay and I'm thinking that's probably my best bet.
I've been looking for some pictures of the engine compartment of a 732. I believe that it's basically the same machine as the 730 but it has a liquid cooled ford engine. Just wondering the location of the radiator and how air is moved through it on that machine. So if anyone has machine similar to my 730 and is willing to share some pictures of the engine compartment / radiator location I would greatly appreciate it.
Thanks Tazza for fixing that picture for me. I was trying to use google chrome and it won't let me post pictures.

Thanks for the input and ideas please keep them coming.

Ah, my 743 has the fins cast into the flywheel. Your idea would work.
The way the 743s are setup is the oil cooler sits just under the radiator. The air blows through both. The chroud is taller than yours, it goes almost all the way to the top of the engine bay. The oil cooler sits almost at the top then.

Kburroug · Apr 7, 2011

Tazza said:
Ah, my 743 has the fins cast into the flywheel. Your idea would work.
The way the 743s are setup is the oil cooler sits just under the radiator. The air blows through both. The chroud is taller than yours, it goes almost all the way to the top of the engine bay. The oil cooler sits almost at the top then.

I just installed a cummins B3.3T in my 632. It looks just like your machine. I took the original fan drive plate and the new flywheel to a machine shop and had them cut the drive plate and drill new holes to match the new flywheel. When I purchased the 632 someone had swapped in the isuzu thermoking motor. It looked like they just drilled new holes in the plate to match the Isuzu flywheel.

Bobcat 730 VH4D to Isuzu Diesel

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