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Converting a zero turn to diesel?


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#16 coldone OFFLINE  

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Posted September 06, 2011 - 09:01 PM

I will take the blown engine. :D

#17 Tennblue59 OFFLINE  

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Posted October 17, 2011 - 09:16 PM

Been busy with other stuff so haven't been able to work on this much, but spent some time with it today.

The diesel I have is a Mitsubishi S3L2. 32 hp @ 3400 rpm, 23 hp at 2300 rpm (continuous load). It would be replacing a 25 horse gas motor, so more than enough power...

But it weighs 276 lbs! Thats over 170 lbs MORE than the original engine, so I may have an issue there...

I measured the diesel as well - width would be no problem. 17" engine in a 23" bay. Height would be ok as well - even with the top mounted muffler, it would only be as high as the seat, marginally higher than original engine.

Big problem is length. With fan and radiator that was in the Toro, I have a 31" package, that needs to fit into a 20" space. I can lengthen the frame, but given the weight load, not sure if the added leverage of the weight farther out back is a good idea...Without the fan and radiator, it's 20", so would fit. Engine rotation requires the engine to go in radiator toward the front - if it went to the rear, I could fudge that better. Mower pto could go off the flywheel and would be only a few inches back from present location - longer belt and everything would be ok there...

Am considering relocating the radiator (to the top or one side) and using an electric fan - that would let me keep the short length, and would maybe make it quieter in the driver's seat, since the fan would be in a different vector from the pilot. Anyone used electric fans instead of the belt powered ones? Would the alternator supply enough power for the fan's draw?

How much lighter/shorter would a 2 cyl Kubota engine be? Am thinking about trying to find a shorter engine if it makes enough power... Less heat produced, smaller package, less weight. What are the dimensions for them?

#18 Cvans ONLINE  

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Posted October 18, 2011 - 09:18 AM

I'm not aware that Kubota made a 2 cylinder that large in the recent past. I know that Mitsubishi, Iseki, and Yanmar did make some larger ones.
I have recently seen a photo somewhere that showed a diesel install with the radiator on the other end of the engine. Your hoses would be longer but it must be doable.
Electric fans are nice. I had to use one on mine and it works fine. Just make sure you get one that moves enough air. I'm using one out of a Nissan Sentra and it does a good job and just fit into the shroud. They do draw some current so you will need an alternator instead of a dynamo to keep your battery charged.
Looking forward to some photos.

#19 Tennblue59 OFFLINE  

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Posted October 18, 2011 - 10:23 PM

This engine has a belt driven alternator - I found a spec sheet for the engine that gave alternator output (don't recall the ## at the moment) so can see what the available output would be - worst case, I could size in a bigger alternator, I should have extra horsepower to drive it... Then to get some current draw specs for electric cooling fans....

Also, pretty sure this has a dynamic coolant pump, not just a convection pump, so there will be plenty of flow through the radiator.

I had initially thought about laying the radiator/fan assembly horizontally on top of the engine to keep the footprint small, but the muffler is up there and there would be some heat from it. Leaning more toward putting it vertically on the injector pump side of the engine facing out to the side of the mower - need to mock up and see if that puts it in a vulnerable place. Or put it in behind the motor...

Will post some pictures soon.

Next step is to test run the engine - it's been sitting in the yard (ran good when put away..) under a tarp for a while. Will probably just run it in the Toro (disconnected, but still in frame) to makes sure it's ok before pulling it and starting the cut and weld!

Thanks for the interest, guys!

#20 Tennblue59 OFFLINE  

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Posted December 03, 2011 - 10:52 AM

An update for those following this "story".....
Started freeing up the diesel engine in the Toro the other day. Basically disconnected engine from the hydraulic pumps (Toro is hydraulically driven, both drive and implements) and bypassed the computer/key system of the mower. Leaving the engine in frame for the time being to make sure it runs good.
Engine spins over fine. Need to find my diesel compression tester set (around here somewhere...) to check the compression. Looks like 1 or 2 of the glow plugs are dead, so will start hunting down replacements for those.
The diesel in the pump lines was thick and yucky, so will need to flush the pump and lines good before I can expect it to fire.
So, project still progressing, just at a snails pace for now.....

#21 Cvans ONLINE  

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Posted December 03, 2011 - 11:18 AM

Nice to hear that your making progress. The bad glow plugs may be the biggest reason that you ended up with this engine. If the fuel system was clean I would say just fire it up and see how it runs. I took one of my engines to a diesel shop and they jury rigged some fittings to check compression. The results weren't favorable and someday I plan to give it a running test and see if my gut feelings are right or not. The working hour meter said only 800 hours.

Thanks for the update.




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