680E Cummins swap

[Kevin Lazer]

I just purchased a very clean Case 680E with a broken connecting rod (punched a hole through the block). It seems these 336BD engines are the trifecta of being unreliable, rare, and expensive. It looks like the newer 680K uses the Cummins 6BT, so I'm wondering the feasibility of an engine swap. Has anyone ever been down this path? I'm suspecting motor mounts and flywheel modifications will be the big projects, but are there any issues that make this project a non-starter?

 

[Tinkerer]

Welcome to HEF, Kevin !
I hope you bought it really cheap. It will take some serious money to do that conversion. The bellhousing for one. Unless someone that has done the conversion and can give you reliable information, I think you should find a 336 or 301 engine and keep it simple.
A 10 second search found a 336 block here.

https://www.ebay.com/itm/Case-336BD...761308&hash=item282044a13a:g:RbAAAOSwjyBcgrah

 

[Swetz]

Tinkerer, That block says it is cracked, but that it has been that way for a while...still not sure I would mess with that one.


I do seriously agree, unless you have a strong appetite for modification and fit and refit, and lots of dollars, the OEM is a better alternative. If there were a swap kit available that worked out all the bugs, that would be different...but that doesnt seem to be the case.

 

[Tinkerer]

Oooops ! Thanks for reading the description that clearly says its cracked. My bad. This is a good example of why parts and part numbers provided to an inquiry needs to be thoroughly by checked by anyone seeking help.
Kevin ; If you are interested in looking for a 336 or 301 do a search for Tractor salvage yards. There are a lot of them that will have those engines.
This picture is one of them.

 

[Kevin Lazer]

Thanks for the input fellas. Tinkerer, I got the 680E for $2,000 with extendahoe and EROP, so hopefully I’m doing alright. I’ve called around to all the nearby tractor yards and every 336 I see has either a broken crank or a spun main bearing, whereas 4BT and 6BT engines are plentiful and under 1/2 the price of a running 336. 336 Re-mans are $7,500, whereas a nice running Cummins can easily be had for under $3000. Also, I’m at 6,000 feet above sealevel so turbos are nice. I read that someone did a 6BT swap into an originally 336-equipped excavator and it was relatively easy, but those don’t have the same spacial constraints of a backhoe. That fella said he had a machine shop modify his flywheel.

Mostly, I don’t want to put another junk engine in this thing and be doing this again next year. I have a an electric forklift that would make fitting as painless as possible.

I’ll stay on the hunt for a decent 336, but if anyone has info about flywheel/bellhousing fitment, I’d love to hear it.

 

[Tinkerer]

That was a decent price for it.
It would be nice if you could find a 680K being parted out. They have the Cummins in it.
Keep in mind that you have a lot of parts on your broken engine that have value or reusable.
Here is lead on 336's.
https://www.vanderhaags.com/Search-...lters[]=REBUILT&filters[]=USED&filters[]=CORE

 

[Kevin Lazer]

It would be nice if you could find a 680K being parted out. They have the Cummins in it

Is there something about the Cummins in the 680K that makes it an easier conversion than any top-turbo 6BT? I’m not having any trouble finding nice 6BTs and SAE#2 bellhousings.

Also, that link you sent is representative what I’ve been finding: lots of hammered non-runners for more money than a clean Cummins. I’m hoping to find one that doesn’t feel like a ticking timebomb.

 

[Tinkerer]

The 680k should be a fairly simple bolt in conversion. Maybe.
The unknown thing for me is if your 680E torque convertor and shuttle will need alteration.
It could get expensive or impossible unless someone that has done it chimes in here with the correct info for you.

 

[Kevin Lazer]

Well I spent a few hours on the phone today calling salvage yards and came up empty handed. A few of the larger yards snickered as soon as I said "336BD." Answers ranged from "goodluck..." to "we've never got one in before without a broken crank or hole in the block." A few places had random parts, but just an empty block and crank are going to run about $2,000.

So far I've found that Cummins uses a #2 bellhousing on 6bt and 4bt motors. If that's not what my 680 has, I can get bellhousings for under $300 from a 580E or 580K backhoe. Then It seems the main project would be mounting my torque converter to the Cummins flexplate, and of course motor mounts which are time consuming but not overly difficult.

 

[Tinkerer]

The Case 301 is the same block as your 336. The liner bores are the difference.

 

[Coy Lancaster]

Have you checked for Case ag tractors the 830 and 930 had the 301 engines in them I do believe.

 

[Shimmy1]

Have you checked for Case ag tractors the 830 and 930 had the 301 engines in them I do believe.

30 series Case tractors do not have direct injection engines. An 830 does have a 301, but a 930 has a 401. An 870 has a 336, a 970 has a 401, a 1070 has a 504.

 

[Tinkerer]

FWIW in your search, Kevin.

 

[Delmer]

30 series Case tractors do not have direct injection engines. An 830 does have a 301, but a 930 has a 401. An 870 has a 336, a 970 has a 401, a 1070 has a 504.

I'd be looking at an ag or Case forum to see what the tractor pullers think would work for a substitute. You could probably find a 970 or 1070 in good running condition with shot tires for $2-3,000.

If you want to go the cummins route, I'd bet the tractor pulling community will be more helpful than we are.

 

[steve wherley]

I just purchased a very clean Case 680E with a broken connecting rod (punched a hole through the block). It seems these 336BD engines are the trifecta of being unreliable, rare, and expensive. It looks like the newer 680K uses the Cummins 6BT, so I'm wondering the feasibility of an engine swap. Has anyone ever been down this path? I'm suspecting motor mounts and flywheel modifications will be the big projects, but are there any issues that make this project a non-starter?

I have a BT6 Cummins 40,000 miles. Removed from motor home and replaced with 220 HP. Has #2 Bell Housing w/Allison flywheel/drive. $3300.

 

[Shimmy1]

I suspect trying to repower a 680E with a 6BT is going to be a challenge. We repowered an 1150C, but that involved going from a 451 (6 cylinder) to the 6BT, which was considerably shorter. That 336 is packed in pretty tight, and the front pump runs off the crank. Not trying to pour water on this, just do some research first.