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Discussion Starter #1
Hey all,

I just bought a Komatsu SK1026-5 Skidsteer and the motor is blown. The price to rebuild that engine is 10-12k, from the local shops due to the main bearings wearing into the block. After finding that out, it was suggested that I buy a 4bt and put in it. I bought one that use to be in a guys jeep. I am trying to find some help locating what kind of bellhousing and adaptors I'm going to need to make this conversion. Can anyone help or at least point me in the right direction?

Thanks,
Derek
 

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What is the bolt pattern on the front of the existing trans? Then one can go to an SAE #2, 3. to the engine. SAE mounting bolts are #3 are 4.375" center to center; #2 are 4.750" center to center.

Ed in .CO.
 

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Is your skid steer the turbo or non turbo model? They came both ways. May prove interesting to adapt the hydrostatic transmission to the Cummins. Original engine would have been around 84 HP. A 4bt would be at least 105 HP or more. Not sure is that is an issue or not. 4bt's were used in Case skid steers but don't know if they share any common parts with a Komatsu.
 

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Hi. We have a 2004 Gehl 7810. Originally had a 115 electronic Perkins. It gave trouble and we put a worn out 4bt in it. I would first start with determining a bell housing. I think you would be best off getting a good engine from a Case 1845 or Case 90xt as examples. They are setup for a skidsteer and would likely be outfitted as close as possible to work in your machine. You want an injection pump setup for industrial/limiting speed governor, not on-road. (ours is on-road and works, but not right).

On adapting our 4bt into skidsteer, some of the items needed was a flat oil pan/oil pick up tube, exhaust tubing, throttle brackets, motor mounts. Luckily for me, the later Gehl 7810E used a 4bt so I purchased some of those parts for our older 7810, such as motor mounts.
 

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There were 2 types of governors used on the Cummins engines. The one used for a road engine is designed so you maintain speed with the accelerator pedal. The industrial type engines generally had a governor that automatically tries to maintain engine RPM. As Seedcleaner pointed out, a road engine will work but will have different characteristics than a off road engine. Same goes for using an off road on the highway.
 

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Discussion Starter #7
Thanks all for your info and suggestions. Sounds like I may be going at this the wrong way. This is what we have at this time. The black engine is the komatsu, and the white plate is like an adapter from the Hydraulic pump that runs everything on the Skidsteer to the bell housing on the komatsu engine. So, sounds like, from you all, that I should go at this a different route.
 

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The Case 1840 and 1845 Skidsteers are very common. One with hydraulic or engine problems can be picked up for pretty cheap, a few grand sometimes. If you had to make this work with a 4BT I would try to find the Case tractor parts or an entire skidsteer to get what you need.

I love the 4BT's and have used a nice Case 1845 with highflow extensively, but I would be inclined to fix the Komatsu engine instead of re-inventing everything.

I'd like to know how you get into $10k+ to rebuild a 4 cylinder diesel. Machine work is not very expensive. I've been involved in some real wreck engine projects where the crankshaft had to be welded, block needed welded and sleeved, head needed welded and every surface had to be re-machined and/or honed. Even at that the total bill wasn't more than $5000 parts and labor. If it needs an injection pump and injectors and a turbo on top of the main line repaired then I guess I could see it, but it doesn't make sense to me.

What engine is in the Komatsu? Komatsu is typically pretty high quality stuff. Komatsu makes some pretty good engines. Cummins had a long period where they used the 3.3 Komatsu and called it a B series. That 3.3 was a fantastic engine. Much better than the plastic filled garbage 2.8ISF Futon engine Cummins replaced it with.
 

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Discussion Starter #9
Ok. Thank you for your input Snuggletough. The couple of shops I asked about rebuilding the motor said it is "$2k-2.5k per cylinder." The PO said he had it at his "mechanic" and he said it would be 8-10k for a rebuild. The block is broken, so I would have to source a new block for it. The Engine in the Komatsu 4D98E Turbo engine. Maybe I need to look at a different shop to rebuild it. I am getting pressure from my boss to get it up and running quickly and cheapest possibly, of course. LOL.
 

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The Komatsu 4D98E is a 3.3.

That's a great little engine. A brand new one on Ebay is $7500. I'm sure you can find one for way less than that for as common as they are.
 

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Discussion Starter #11
Well, I'll have to look. I'm limited to be able to spend 5k, without having to get Corporate involved and getting Capital money involved. I'll look more, I guess.... Other than I just spend 3k on this 4bt, just to not use it.
 

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May or may not help, earlier thread on here. You may have luck if he wants to offload the housing and flywheel if they are the right size.
Cheers Steve
 

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Discussion Starter #13
Thanks.. looks like the mounting plate that the hydraulic pump mounts to is SAE 4. Found some 4BT to SAE 3 flywheel housing/ adapters, but not to SAE 4. So found another Adapter from SAE 3 to SAE 4. So, now I need to find a 12" flywheel to mount to this, "flexplate" that runs the input of the pump.
 

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Any flywheel that suits the #3 housing and starter should work with a little machining or adaptor ring
Cheers Steve
 
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