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West Central Minnesota | I am admittedly no expert on MM power units, but have had the opportunity to visit with people with vast amounts of hands on experience. MM was one of the very first tractor related companies to use propane and natural gas as a fuel. I believe Cat preceded them. It seems that either of these fuels works quite well with the long stroke engines. What surprises me is that an engine that was designed possibly over 60 years ago can still be considered a viable power unit today.
Although not an irrigation application, I toured an ice cream plant in suthern Minnesota a few years back that used MM 800 cid engines for the manufacturing process. They had a total of nine engines...a max of eight in use at one time. Number nine engine was a back unit that came into play when one of the others was down for maintenance. When a fresh batch of ice cream was produced, all eight were needed to freeze the product. Maybe only two were needed to maintain temps after it reach the final temp. The engines ran on natural gas. They were all plumbed into a common cooling system and each engine had water cooled oil pans so that if one or more engines had to be place into service they could be put under full load in a couple of minutes because they were completely warmed up before they were started. This common cooling system had a heat exchanger that was used to preheat the ice cream recipe when a new batch was started. All engines were plumbed into a common exhaust system that used another heat exchanger used to heat domestic water used throughout the large building. The maintenance supervisor stated that they expected around 50,000 hrs between overhauls. Crankshafts and camshafts were seldom a problem because of the size of journals, so they would bore the blocks .020" each time until they reach the max of .060" and then they pushed in a dry sleeve and started all over again. Naturally, heads and valves were done periodically.
The annual reports prove that the power units were MM's most profitable segment of their business. With the financial problems the company had, maybe they should have pushed that part of their operation a little harder!!
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Minneapolis moline question.
