Kubota or Yanmar, that is the question
 

So I've been doing research and can't really decide which is a better engine.
kubota or yanmar? Any suggestions?

no comparison
 

3tna72 yanmar, hands down. Can be found in jd f900 series and in i believe 755 jd utility tractors. Only downfal that motor you have to get internals from deere only. Spun'em over 6000 rpm with aftermarket injection pump and turbo.

Do you know the size of that one? I found a little yanmar out of a 332 John Deere.
I forget the size of the engine.

how big you say?
 

I believe the 3tna72 is about 880cc and 22hp, the 332 should be a 3tn66 and 710cc and only 16hp. Dont quote me but I am pretty sure of those numbers.

Actually I checked on it after I asked and you're right.
it's hard to find one of these motors. I did find one but its across the country!
Now would the 3tna72 be better than the 3tn66 just cause of the size?

does size REEEAAALLLYY matter?
 

In the world of pulling there is no replacement for displacement. I'm not sure what the major differences in build are between the two motors, But I know what we put ours through.

Well some clubs like to limit you on displacement, but how are they to know what it has? I've been looking for aftermarket pumps and have had no luck... is that a special order? Same goes for the turbo... I was thinking of getting a Turbo from a Dodge spinter van. They aren't to big of a Turbo I think. Now for a clutch, what did you guys use? I've seen the clutches You can get for kohlers. They support like up the 60hp, but I'm assuming the little yanmar will make more than that?

A Dodge Sprinter is very large...the turbo'd Kubotas I've seen use the turbo from a Smart car.

It all depends on how much fuel is being pushed through it if it'll spin that sprinter Turbo. Not to mention some internal work. Do you know the specs of a smart car Turbo?? I'm guessing its smalled than a grown mans fist!

I don't know the specs. You don't want to over-boost the engine. I don't know much about these, and I'm guessing a lot of people on this forum don't either. You might want to look for a garden tractor pulling forum.

I'm not necessarily worried about overboosting the engine at this point...it would be more testing. Are Diesels kinda new to the lawnmower pulling world? I hardly ever see a diesel puller compared to an alcohol or gas motor...

If my memory is working with me we used turbos off geo's from the early to mid 90's. As far as aftermarket pumps go, its all custom fabricated adaptations of larger pumps onto smaller motors. Honestly I think we had about the only LARGE pump around.

Oh yeah "overboosting" if you call yanmar or kubota tech they will tell you any boost is too much boost. Rebuilt the motor in a dixie chopper once think it was a yanmar 3 cylinder 3t84 or 82 something like that it was a turbo charged motor from factory even though its a bigger motor that turbo would probably work, on account of your going to wank to see 4000 rpm or more.

The pump on the yanmars are already pretty big! Couldnt I just have the pump sent out to be tuned? As for boosting the motor, how about yeti g the pistons shaved down the support more compression from the Turbo? Or will it support the extra boost it'll get? Sorry for all the questions but that's what a forum is about right?

The pump housing on the 72 yanmar is part of the timing cover, and that is the biggest set of guts available for that housing. The fisical size of the pump is not the determining factor the fuel delivery is. On the newer yanmars and the bigger ones, the pump is removable as a whole unit (housing unbolts from timing cover.

oh yeah
 

BTW in the circuit we ran in I think my tractor was the only tractor with an upgrade that extensive. Almost forgot ford mustang two clutch was behind diesel and alchohol motors. Cub lowboy clutch behind stock motors.

So how did you get the pump out yours to put that bigger one in there? The 66 yanmar the pump is the same way as the 72? Maybe I can just turn the pump up? Oh boy this Tractor is gonna be heavy with this diesel and a heavy clutch.

My old man machined the pump housing off the timing cover and welded a flat mounting plate in its place. Then we had a new gear made for a larger 3 cylinder pump. I believe the 66 is built the same. I can check into that. You can turn the factory pump up (like any other) you are just limited to the size of the barrels in it. you may also want to shave a little weight off of the governor wieghts, but be precise. Same amount off each one.

wow
 

Wow that's cool... well I'm sure they are the same. So what kind of HP would be made by just turning it up? Like 20-25 at the most? So if I take weight off the governor that would just give me a little more rpm?

Taking weight off will make it more "flighty" ,that and a heavier spring pulling against it will allow you to runer up there in rpm. Keep in mind untill we put the engine on a dyno we had no clue how many rpm we were turning. In the stock class we were alowed 4000 or 4500 and that was checked with a photo tach. After that they made diesels in our association a 3 cylinder open class and allowed turbos, at that point no one wanted to stand next to the motor to tach it. P.S. if you are going to run past that 4500 mark I would recomend 1/4 aluminum side plates (covering the length of the block) bolted to the frame and side shields on the tractor.

So how much HP did your engine make? Well there's all those rules on covering the engine and the clutch. Using billet steel and the clutch. Plus I need a valve to shut down boost if something were to happen. The hardest part is that since there's not much out the for performance parts I have to have most everything made.

sorry no numbers
 

The dyno we barrowed didn't register below 200hp so I can't tell you horse numbers. We just needed to be able to load the motor back to back times to make adjustments and monitor temps. Boost shutdown is easy use an exhaust flapper opperated by a morse or choke cable to cover air inlet to turbo. A local machine shop can turn out a steel flywheel for you.

Well that's to bad u couldn't find out what it had at the time. Yeah I was just thinking about that, wondering where id get a flywheel. Another thing, did you use an automotive drivetrain to get all the power to the ground? A lot of people I've notice are using a dart rearend. I was just going to use a cub transmission but I know ill tear it up pretty quick.

Your not seeing the trick. You use a dodge carrier with a cadet ring gear bolted to it, inside a cadet transmission. The common thing to do is eliminate rev. and add another forward gear. Also you can get a front reduction gear set to further change your ratios. Check out midwest supercub that will give an idea of whats available for gears. My diesel had a 10% overspeed in the front reduction and a 27 tooth high gear (one tooth of overdrive, 26 is 1:1)
I ran a 26 x 12 x 12 bar tire.

P.S. If you think you can control it and the rules dont say "no limited slip rearends", you can fit a dodge cone type limited slip into the rearend however its tight.

Ah yes I got it now. And it is a tight fit. A little grinding is necessary, but after that, all is good. I've looked into the get sets they have so I know what my options are. So basically once the carrier is installed just have the Dodge axle shafts shortened and all is good!