[AJD] Two Cylinder JD's and Power Driven Equipment

[J.R. Hobbs]

This is opinion and experience, not necessarily knowledge on my part. I think the part about a two-cylinder tractor being harder on the bearings of a belt-driven machine is bunk, simply because the transmitting medium, the belt, would have absorbed the shock of the uneven firing, and the bearings would never notice.
   
  However, I do believe that on loads that required every ounce of power, such as a "fuel racks set wide open"  "720" Diesel with about 70 horsepower on a 4-row 707 stalk cutter in heavy corn stalks, they were definitely harder on U-joints than a multi-cylinder tractor would be. With the "720" powering the 707, getting a year's service out of a set of U-joints was doing well. When the same cutter was powered with a 4010, U-joint life was tripled. Some of this might have been because of slightly different power delivery angles, but I believe that it was mostly because of the smoother power delivery at relatively high horsepower ratings. And, had the PTO's been 1000 rpm instead of 540, I think that would have made for longer U-joint life for the two-cylinder.
   
  However, on machines not requiring full power, such as mowing machines, etc, we never really saw all that much or any significant difference in U-joint or bearing life. So, I think your conclusions are correct, and that in most cases, it is indeed a myth, perpetrated largely by the kind of people I like to call Binderoids.

Duane Ledford <dledford at classicnet.net> wrote:
  
Thought I would ask you folks what your opinion and knowledge is about this. Have 
ran across several individuals who claim that if you use any type of PTO driven or 
belt driven equipment on a two cylinder JD, that the bearings of the equipment will 
be ruined. Their reasoning is that the uneven firing of the two cylinder engine 
pounds on the bearings, universal joints, etc. I might be able to see this if you 
were lugging the tractor for an extended time. But if this is true, wouldnt every 
bearing in the tractor be subject to this pounding, therefore need frequent 
replacing? Bearings wear out, but I really haven't seen any more frequency in JD's 
bearings needing replaced over any other brand. Has anyone done or heard of a 
study of this "rural myth?" Would be interesting to see measured results of the 
differences in stress on equipment between the pulsing two cylinder engines over 
the smoother running four and six cylinder ones. What has been your experience? 
What do you think? 



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