MF 860 Repowered By Cat 3208 Diesel

When the crankshaft broke in the 540 Perkins diesel that powered his Massey Ferguson 860 combine, custom harvester Pat Minahan found out that repairing or replacing the Perkins would be expensive. And he would still have the Perkins, which he had never liked that much.

Pat Minahan was about as familiar with the Perkins as you could be since he had worked 17 years as a mechanic in a Massey dealership and later started a custom harvesting business.

He decided to "upgrade" to a Caterpillar 3208 diesel rather than fix the Perkins. "I was surprised at how well it worked out. It took very little machine work and no changes to the sheet metal on the combine. I was able to use the original fan belts and pump belt. Best of all I ended up with an engine that's got a lot more power and uses less fuel," says Minahan.

The 3208 came out of a New Holland TR70 combine. One of the first jobs was figuring out motor mounts. He set the Perkins on the shop floor next to the Cat and started measuring. He made new mounts out of heavy strap iron. Then he had to machine an adapter plate to go between the Massey's bell housing and a flat plate on the end of the driveshaft coming out the back of the engine. He also had to machine a drive plate to go on the flywheel. He used the original Perkins starter but installed a Cat electric fuel pump. The only major change to the engine itself was making a new oil pan. He cut off the bottom of the existing pan, which was too deep on one end, and welded a new pan to the bottom of the old flange. The new pan runs 7 in. deep for the entire length of the engine, giving him significantly more oil capacity than before. "I like having more oil in the engine," Minahan notes.

He also installed dual exhaust, using manifolds off a White 4-WD tractor and oversized 3-in. dia. exhaust pipes that run to mufflers off 720 Deere tractors.

The extra power of this engine makes a big difference. It's 100 cubic inches bigger than the Perkins. One thing we had to deal with is that the engine runs about 200 rpm's faster, which speeds up all the cleaning components on the entire combine. I wanted the combine to run a bit faster but not that fast, so we had to machine down the main drive pulley on the separator. I worked with a friend who is a machinist to calculate how to do it. We took 1/8-in. off the circumference of the pulley, which slowed it down about 100 rpm, so it's still running about 100 rpm's faster than it did originally.

"That extra speed -- plus the added power -- really makes this combine perform. I run faster and do a better job and the machine doesn't bog down and throw crop over like it did before. I've used it for two harvest seasons now, running from Oklahoma to Minnesota with no problems," says Minahan, who notes that he would consider making the conversion for other farmers, or he could put together a do-it-yourself kit.