Case 850b 4bt conversion

[zswar]

I have a Case 850b that spun a bearing and ended up blowing a decent sized hole in the side of the block. I have a 4bt cummins sitting here and was wondering the cost/ work required to drop it in. I know the newer C's and Ds came with a 4bt so the sizing will be fine. I asssume the bell housing might be different and minor fabrication may be required but the swap seems like it would be worth it rather than tracking down a new block and buying a rebuild kit. Any input helps. TIA

 

[Tinkerer]

The challenge you would have to deal with would be getting the 4bt flywheel to bolt up to the flex plates.
You may need a machine shop to modify the flywheel to get the bolt holes to line up.
Then you may have problem with an out balance assembly after it is bolted together.
That isn't something I would ever do.
Even after doing that the torque convertor to the transmission have to be the same distance like it was with the 336.
I think replacing the 336 with another one is the best option. You could use a 301 to replace it.

 

[ozarkag]

I've done a number of repowers, and while I prefer not too, anytime your swapping to a 4bt it's a good move.
The physical size is the main consideration, and sounds like should work for you. A good machinist can usually solve the flywheel coupling issues. Hayes also will custom build couplings. Might even be able to purchase bell housing or whatever from a C or D.
Seems it's often one of the " little " things, such as intake, exhaust, coolant hoses, throttle that ends up taking a lot of time and ingenuity to get to work.

 

[alrman]

Distance from fan to radiator will also need to be considered.
The 850D used the 6-590 engine. In saying that, the 850B chassis will be different to the D.

 

[MG84]

Yeah a 3.9 Cummins seems too small for an 850 dozer or loader. Weren't all the later 850s the 5.9 six cylinder Cummins?

 

[Tinkerer]

The 850C was last model that had the 4 cylinder 336 in it.
The 850D was the first with the 6T-590.

 

[MG84]

Looked at some specs, in some of the highest power levels case offered the 4T-390 was about the same power as the naturally aspirated 336. However it made that power at a higher rpm. Probably not an ideal swap but it may work.

 

[zswar]

Well for anyone that was curious the swap was a success and the dozer is back up and running, some serious custom work had to be done, not a bad way to wrap up a senior project

 

[materthegreater]

No pictures?

 

[zswar]

Heres a video of it, i have more pictures if anyone is interested in certain aspects of the swap

 

[materthegreater]

What model is that winch?

 

[zswar]

What model is that winch?

Case Gearmatic Model 19

 

[materthegreater]

Cool, same as what's on my 450C. Mine is missing the fairlead though.

 

[Rosteven]

Zswar, I want to do the same any pics or list of parts to make a 4BT fit would be a great help please.
my 301 has had its last life balencer fell off operator did not stop quick and a rod has come through the side, forth time in 50 years so would be nice to have the 4BT