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Making The Mf10/12 Varidrive Put The Power Down


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#1 MF10 DIESEL OFFLINE  

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Posted April 29, 2013 - 09:25 PM

My tractor really isn't for competitive pulling, but has belt slippage issues when I pull heavy loads around the yard. Like wagons full of rock or my 8500# 2.6 Dodge diesel sled puller when it dislocates parts on the track.

 

Anyhow the lister petter's crankshaft is slightly ahead and up from the original gas engine location so it seems the rear belt just isn't tight enough to hold the low rpm torque of the diesel in higher gears (3rd up) towing heavy loads. It will climb an approximate 40 degree grade in 4th low unloaded. I have messed around with the varidrive several times, but it seems I can only just make it work good enough. I have thought about adjusting the width of the rear pulley. I have never got the front end to lift under load, in lower gears it will spin the 23x10.50x12 carlisle ag tires at idle if it can't get enough bite.

 

I had read about modifying the rear belt tensioner for pulling, I am curious what my options are?


Edited by MF10 DIESEL, April 29, 2013 - 09:26 PM.


#2 DH1 ONLINE  

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Posted April 29, 2013 - 09:38 PM

I find on heavy pulling loads in 3rd or 4th gear, the clutch pedal will go down on it's own, slowing the tractor down, lifting up on the pedal when this happens puts more load on the engine and the tractor speeds up.

There is 1 big spring that is part of the Vari-Drive system and I believe that if you double up that spring, increase the tension it will not go down on it's own as much or easily.

First thing IMO you should do is make sure everything is adjusted and set properly.



#3 Dieselcubmike OFFLINE  

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Posted April 30, 2013 - 12:03 AM

MF I wish I could help but unfortunately I know nothing about the masseys and the belt tensioner :( Though I would try what DH said and go from there. 



#4 1978murray OFFLINE  

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Posted April 30, 2013 - 07:34 AM

make sure there is no play in ur pedel when pulling.



#5 EricFromPa ONLINE  

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Posted April 30, 2013 - 07:36 AM

Toss in a heavier spring on the rear tensioner.

 

I've thought about eliminating the varidrive set up on my JD and just run 1 longer belt,like the older Sears GTs but I would have to either move the engine pulley or the engine it's self to line the engine pulley up to the tranny pulley.After that I could no longer use any PTO driven attachments though.It Would be a good mod for a Puller though.   



#6 Alc OFFLINE  

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Posted April 30, 2013 - 07:51 AM

I guess with any type of varidrive ( like whats on my DB walkbehind ) you can only make the belt so tight ? 



#7 MF10 DIESEL OFFLINE  

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Posted April 30, 2013 - 11:36 PM

Toss in a heavier spring on the rear tensioner.

 

I've thought about eliminating the varidrive set up on my JD and just run 1 longer belt,like the older Sears GTs but I would have to either move the engine pulley or the engine it's self to line the engine pulley up to the tranny pulley.After that I could no longer use any PTO driven attachments though.It Would be a good mod for a Puller though.   

 

I don't know how much advantage there would be to staying with a belt drive and eliminating the varidrive. It's still a belt. I know I'm sticking with the varidrive, the idea of a manual transmission with what is essentially a torque amplifier is worth the hassle to me. I wish somebody would chime in with a known spring recommendation for the rear tensioner, hardware stores are getting really sparse for selection anymore.

 

All I know is that I've seen a MF10/12 variable speed wheel stand out of the hole with a sled online somewhere, so the varidrives can be set up to hold alot more power than mine is now. It won't ever be a shaft drive machine, but if it will pull a wheel under load it'll work for me. 


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#8 ducky ONLINE  

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Posted April 30, 2013 - 11:57 PM

"All I know is that I've seen a MF10/12 variable speed wheel stand out of the hole with a sled online somewhere, so the varidrives can be set up to hold alot more power than mine is now. It won't ever be a shaft drive machine, but if it will pull a wheel under load it'll work for me. "

 

Thanks MF 10 we were able to do that years ago and smoke 26x12 tires on blacktop.  Just to let people know it is possible.



#9 HowardsMF155 OFFLINE  

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Posted May 01, 2013 - 01:59 AM

"All I know is that I've seen a MF10/12 variable speed wheel stand out of the hole with a sled online somewhere, so the varidrives can be set up to hold alot more power than mine is now. It won't ever be a shaft drive machine, but if it will pull a wheel under load it'll work for me. "

 

Thanks MF 10 we were able to do that years ago and smoke 26x12 tires on blacktop.  Just to let people know it is possible.

So, Ducky, the $64,000 question is "How did you do that?"



#10 broken2 OFFLINE  

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Posted May 01, 2013 - 10:47 PM

I have multiple mf10's/12's and only had problems with belt slip once. The problem was the front belt(crankshaft to varidrive) was worn to thin and was bottoming in the crankshaft pulley, the belts are supposed to grip on the sides. I installed a slightly wider used belt and the tractor would spin, wheel stand or stall before it slipped. If the base of your crankshaft pulley is clean and shiny than your belt may be bottomed out. If that's not it you could try removing some/all of the shims form your rear pulley, it should make the belt ride higher in the pulley, depressing the tensioner spring further. When I modified one of my mf12's so I could mount 26x12x12 superlugs on it I also modified the rear tensioner spring while I had the tractor apart. The rear spring pushes for tension instead of pulling and has to be the correct size inside and out so it's kind of hard to find a suitable stronger replacement. I stole a another spring from a parts tractor, cut it in half and added it to the original spring. I don't know if it was really necessary but I can tell you belt slippage is the not a problem on that tractor. I twisted/broke an axle while plowing in forth gear and another time I actually broke the tranny case, no belt slip unfortunately.


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#11 Alc OFFLINE  

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Posted May 02, 2013 - 05:55 AM

Thanks broken2 , didn't dawn on me that if the spring in those pulleys got weak it would cause problems ,



#12 ducky ONLINE  

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Posted May 02, 2013 - 09:32 AM



"All I know is that I've seen a MF10/12 variable speed wheel stand out of the hole with a sled online somewhere, so the varidrives can be set up to hold alot more power than mine is now. It won't ever be a shaft drive machine, but if it will pull a wheel under load it'll work for me. "
 
Thanks MF 10 we were able to do that years ago and smoke 26x12 tires on blacktop.  Just to let people know it is possible.


So, Ducky, the $64,000 question is "How did you do that?"


Yes we did it the same way we at it spring tension to the rear idler

Sent by Ducky from my Motorola Droid M
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#13 MF10 DIESEL OFFLINE  

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Posted May 04, 2013 - 09:12 PM

Has any body ever tried shimming up the rear tensioner spring with washers? I realize there is a limit to the amount that could be added,  but I have a lathe and can make some custom hardware. I will also look at the varidrive pulleys but honestly don't think I will find anything wrong, I inspected all of them when I first did the diesel conversion.

 

I think my issue is different than most, my engine crankshaft is ahead and up from the original. The engine belt is pulled forward of where it should be so all the adjustments of the varidrive are off a little bit.



#14 MH81 ONLINE  

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Posted May 05, 2013 - 07:16 AM

Is there any way to make a new tensioner that would have variable adjustment? Then you could "dial it in" without tearing it apart 53 times...




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