Bobcat 310 repower

Help Support SkidSteer Forum:

Hotrod1830

Well-known member
Joined
Sep 14, 2010
Messages
513
Been Working on this for a couple weeks. I recently got a Bocat 310. Although the Original Kohler K341 16hp ran decent, it just wasnt as smooth as I would like, and seemed a bit under powered. Add to this it has 1200 hours on it, and the decision was easy When I came across a 25hp kohler V-twin. But, it was in and running before I got the camera out. Yes, it will fit, but it is tight. It IS NOT a bolt in. Several big points are the Closure plate(where the clutch coil bolts to) Needs to be milled flat. The new Kohlers have a "multi fit" pattern that has one set of mounting holes stepped up. Otherwise, the clutch will sit out about 1/4" too far if left unmachined. No big deal, about 15 minutes in the mill and it was done. Just mill all 4 pads to the same height and your ready. Not sure if all the new kohlers are like this, but the ones I have seen are. You will need to install a flexible fuel filler hose and relocate it to clear the larger blower housing. You will need to drill for new mounting holes. I reused the original engine mounts, so the holes where 1 1/4". Easy work for a plasma cutter. location will need to be determined with a "Dry" install. You will need to lengthen the engine "strut" rod a 2-3 inches. A new ignition switch will be needed, as this engine uses a magneto ignition and needs to be grounded to kill it. I used a magneto specific switc havailable at most parts stores. You will need longer belts. easily measured for once the engine is in. I had to "clearance" the hydraulic lines in the rear of the compartment by gently prying them apart to clear the rear valve cover. Last but not least, you will have to trim 1-2 inched off the battery box to clear the oil filter. ( I had to fabricate a rear cover because mine was damaged, and I made it deep enough to clear) You can get a smaller size battery to fit with plenty of CCA's I found an engine with a 1 1/8" x 3.75" shaft, so the factory drive sheaves fit perfect. http://i213.photobucket.com/albums/cc102/bigblocknotch/bobcat31025_zps9edb4899.jpg
bobcat31025_zps9edb4899.jpg
 
OP
OP
H

Hotrod1830

Well-known member
Joined
Sep 14, 2010
Messages
513
Couldnt figure out the pictures. Copy and paste to your browser till I figure it out. Brad
 
OP
OP
H

Hotrod1830

Well-known member
Joined
Sep 14, 2010
Messages
513
Nicely done!! Thanks for sharing!
Just an update on this. After putting some hours on this, I had to put a heat shield on the muffler to protect the back of the cab and wiring/hydro lines. It got the back of the cab hot enough to burn the back of my arm while sitting in the seat.
Also, this thing has plenty of power. You almost cant stop it. A pleasant outcome after constantly stalling the old 16hp kohler.
 

Tazza

Moderator
Staff member
Joined
Dec 7, 2004
Messages
16,829
Just an update on this. After putting some hours on this, I had to put a heat shield on the muffler to protect the back of the cab and wiring/hydro lines. It got the back of the cab hot enough to burn the back of my arm while sitting in the seat.
Also, this thing has plenty of power. You almost cant stop it. A pleasant outcome after constantly stalling the old 16hp kohler.
Gotta love it when a plan goes so well. Excellent engine choice.
I never would have put that much thought to the heat from the muffler, how does the engine go with the heat too? does it have some sort of fan to help move the hot air away?
 
OP
OP
H

Hotrod1830

Well-known member
Joined
Sep 14, 2010
Messages
513
Gotta love it when a plan goes so well. Excellent engine choice.
I never would have put that much thought to the heat from the muffler, how does the engine go with the heat too? does it have some sort of fan to help move the hot air away?
It just has the blower on the flywheel. The shrouds do a good job of keeping the air moving around the heads and Oil cooler. With All the air holes in the sheet metal, I dont think engine compartment heat will be an issue. My only concern is the exhaust points at the back door, and heats it up, along with the battery. It was like that originally, so I guess Ill let it ride and see what happens
 

Rogerat1

New member
Joined
Sep 10, 2015
Messages
3
It just has the blower on the flywheel. The shrouds do a good job of keeping the air moving around the heads and Oil cooler. With All the air holes in the sheet metal, I dont think engine compartment heat will be an issue. My only concern is the exhaust points at the back door, and heats it up, along with the battery. It was like that originally, so I guess Ill let it ride and see what happens
Hi I am looking at doing a similar setup I have a 18hp V twin briggs that I am going to fit to my 310, could you give me the diameter of the drive pulleys on the engine as there was no engine when I got it.
 
OP
OP
H

Hotrod1830

Well-known member
Joined
Sep 14, 2010
Messages
513
Thanks for that, I take it the low speed drives the hydraulic pump.
The hydraulic pump is driven by the high speed pulley belt, with a Small belt that rides under the large belt as a back-up if the main belt breaks. In the case of the 310, both belts are always turning, as they both connect to the gear case pulley.. It depends on whether you have selected the High speed drive, or the low speed drive as to which one supplies power to the Gear case pulley. If you dont intend to install 2 electric clutches on your machine, Select a single drive pulley and line it up with the pump. Pick a pulley size in between high and low for overall speed and power. BTW, My hydros are kinda slow in low speed, but really get with it in high.
 

Rogerat1

New member
Joined
Sep 10, 2015
Messages
3
The hydraulic pump is driven by the high speed pulley belt, with a Small belt that rides under the large belt as a back-up if the main belt breaks. In the case of the 310, both belts are always turning, as they both connect to the gear case pulley.. It depends on whether you have selected the High speed drive, or the low speed drive as to which one supplies power to the Gear case pulley. If you dont intend to install 2 electric clutches on your machine, Select a single drive pulley and line it up with the pump. Pick a pulley size in between high and low for overall speed and power. BTW, My hydros are kinda slow in low speed, but really get with it in high.
Appreciate your help will let you know how it goes when I get it all together.
 
Top