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How To Make An Engine Last Longer
n a recent issue of FARM SHOW there was a brief mention about diesel engine cylinder liner corrosion. Engineer Kevin Johansen, Mound, Minn., contacted us with the following comments.
  "I now work with big railroad maintenance equipment of 4,000 hp. and up, but I did a lot of farm mechanical work years ago. At that time, we knew almost every farm engine we tore down would have tapered wear in the cylinder. The widest, belled-out part of the cylinder is at the top. Wear decreases towards the bottom, resulting in the familiar taper to the cylinder. This taper was attributed to mechanical wearing due to the piston side forces. It was one of those folklore items that Ševerybody knows is true'.
  "However, I noticed that the hardest-working engines, which should have had the most wear, seemed to have the least taper. The bores might have more overall wear, but the wear was more uniform with little tapering. Those with the most severe tapering were the chore tractors ű small loader tractors that got started and used every day, in all kinds of weather. Often for only a short time.
  "The second clue to solving the problem is that the side forces of the piston are not at a maximum at the top, where the wear was the greatest, but further down the stroke. I ignored both these signs because of what I ű and most other mechanics ű knew to be true.
  "Several years later, while doing research on diesel engines, I found an SAE research paper on cylinder corrosion during the cold startup of an engine. The essence of the paper was that byproducts of combustion can condense, form acids, and attack lubrication and the cylinder liners underneath. The acids are worse at the top of the cylinder since they are exposed to the wall the longest. There is a critical temperature range of between 100 and 160? F. Above and below that range, less damaging acids are formed.
  "Bingo. Chore tractors are started up 365 times a year to get 300 hours on them. Big field tractors are started up 25 times a year to get the same 300 hrs. on them. So engine wear in the big tractors is more truly wear due to hard use. Wear in the smaller engines is more from corrosion and loss of lubrication.
  "What this taught me is that getting longer engine life involves four simple, easy steps:
  "1. Maintain the cooling system, including fluid and pressure cap.
  "2. Get the engine hot as soon as possible to get through those damaging temperatures. Keep the thermostats working. Cover the radiator with cardboard. Use block heaters or oil pan heaters. I have a stick-on oil pan heater wired together with a block heater on all vehicles. I plug them in at night and have a simple 24 hour timer that comes on an hour before I need the equipment the next day.
  "3. Change oil frequently to get the acids and particulate out of the engine.
  "4. Always question the Šconventional wisdom'. Like someone said, ŠIt's not all the things I know that cause me problems, it's the things I know that ain't so.'"
  Contact: FARM SHOW Followup, Kevin Johansen, 2148 Basswood Lane, Mound, Minn. 55364.

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2000 - Volume #24, Issue #2