700 series repower...anyone done it? What did you use?

[kilohertz]

The time has come to repair/replace the Wisconsin VH4D in my 720. It has been running rough for the last few months and I decided to pull it apart to find the trouble. Turns out there is enough carbon jammed under the intake valves to sink a battle ship, amazing any fuel/air gets in at all. The guides are pretty worn as well. Also #2 cyl is wallowed out at the top, about an inch down the wall, plus same cylinder has a ring mark about halfway down, barely feelable but still there, probably from when it sat for 3 years after it previously died at the old owners place. Compression was down to 60 psi on 3 of the 4 cylinders, #2 was 10-30psi depending on the day. It's been running okay for the last few years but now she needs a big overhaul. The machine itself is in great shape, and everything else works fine. The engine was rebuilt 1500 hours ago, in 1998 and at that time .030" pistons were installed, so I don't think re-boring is possible from what I have read, so it would be sleeve and start at standard bore again, expensive. So I can just hone and re-ring it, gouge out the carbon, do a valve job and run it until it finally dies, or repower it with something else, my thought would be a nice little Kubota or Isuzu Diesel. That in itself would be a project, rad, cooling drive coupling etc....but would really make it more robust and reliable in the long run.

So I would like to hear from anyone who has put in another engine in any of these 700 series, and what did you use? Pictures? Etc? Or do I rebuild the VH4D and hope for the best?

Thanks all!
Cheers

 

[Hotrod1830]

No personal experience in repowering one, but I can offer some wisdom.
You can find used, standard bore jugs for the wisconsin. But, sleeving the ones you have would be cheaper. The cylinders are probably galled because it probably overheated at some point. Possibly an oiling problem or fueling problem as well, but would have to be investigated if you plan to rebuild it and run it again.
As for repowering, I seem to remember at least one case where someone put a briggs 35hp v-twin in an older bobcat. I think they make them up to 38hp now, but again, they are far more $$$ than rebuilding yours alone.

 

[alchemysa]

No personal experience in repowering one, but I can offer some wisdom.
You can find used, standard bore jugs for the wisconsin. But, sleeving the ones you have would be cheaper. The cylinders are probably galled because it probably overheated at some point. Possibly an oiling problem or fueling problem as well, but would have to be investigated if you plan to rebuild it and run it again.
As for repowering, I seem to remember at least one case where someone put a briggs 35hp v-twin in an older bobcat. I think they make them up to 38hp now, but again, they are far more $$$ than rebuilding yours alone.

You can get 40 thou pistons for the VH4D. You can even get 60 thou pistons.
http://www.agkits.com/wisconsin-vh4d-gas-inframe-overhaul-engine-rebuild-kit.aspx#.WO66rKIlGUl
$338 for a basic rebuild kit. Much cheaper than fitting sleeves.
I'm currently reassembling my VH4D. I've been describing some of the process here. The boring cost me about $240 Australian. These engines are pretty simple and the parts are cheap. You dont need ny fancy tools. Spanners, sockets and a torque wrench will do most.
http://www.skidsteerforum.com/DesktopDefault.aspx?tabid=54&frmView=ShowPost&PostID=97329#98589
I dunno about the US, but here in Australia even clapped out Wisconsins seem to command good money.

 

[kilohertz]

You can get 40 thou pistons for the VH4D. You can even get 60 thou pistons.
http://www.agkits.com/wisconsin-vh4d-gas-inframe-overhaul-engine-rebuild-kit.aspx#.WO66rKIlGUl
$338 for a basic rebuild kit. Much cheaper than fitting sleeves.
I'm currently reassembling my VH4D. I've been describing some of the process here. The boring cost me about $240 Australian. These engines are pretty simple and the parts are cheap. You dont need ny fancy tools. Spanners, sockets and a torque wrench will do most.
http://www.skidsteerforum.com/DesktopDefault.aspx?tabid=54&frmView=ShowPost&PostID=97329#98589
I dunno about the US, but here in Australia even clapped out Wisconsins seem to command good money.

Thanks guys,
Hotrod, you just reminded me (I hate getting old) I have a spare engine out in the back 40, it came with the Bobcat but some parts are missing and it has been outside since it was removed from ??? so will probably be a beast to disassemble, drill and tap all the head bolts, etc..but maybe the valves would be usable...if I buy a drum of ATF and a drum of Acetone, I might be able to fill an old bathtub, soak it for a week and get it apart.
Alchemysa, as I am under the Queen's rule as well (Dominion of Canada eh?) I have found 1 good Wisconsin at a friends farm, in a hay bailer currently being used as yard art...his folks won't let me have the engine. $338 is cheap in USD but by the time it is here, shipping duty taxes etc, it's approaching $600. Still cheap but at that point, a nice little VW Diesel or ?? is possible.
I will have to get the other head off and see how it looks..probably the same.
Cheers

 

[alchemysa]

Thanks guys,
Hotrod, you just reminded me (I hate getting old) I have a spare engine out in the back 40, it came with the Bobcat but some parts are missing and it has been outside since it was removed from ??? so will probably be a beast to disassemble, drill and tap all the head bolts, etc..but maybe the valves would be usable...if I buy a drum of ATF and a drum of Acetone, I might be able to fill an old bathtub, soak it for a week and get it apart.
Alchemysa, as I am under the Queen's rule as well (Dominion of Canada eh?) I have found 1 good Wisconsin at a friends farm, in a hay bailer currently being used as yard art...his folks won't let me have the engine. $338 is cheap in USD but by the time it is here, shipping duty taxes etc, it's approaching $600. Still cheap but at that point, a nice little VW Diesel or ?? is possible.
I will have to get the other head off and see how it looks..probably the same.
Cheers

Kilohertz.... those prices include 'ground shipping'. Maybe they will do you a deal on that. Anyway, they weigh next to nothing so its not a heavy or large package. Over here theres no duty on imports under $1000 (for now!) so all I had to cover was postage, and a friend in the US handled that for me.