# main bearing for D7 pony



## mce5802 (Nov 14, 2014)

Just thought I'd post a couple pics of the main bearing I recently turned for my caterpillars pony motor. The blank was cast out of aluminum pistons, I read that they were a suitable alloy for this application. Guess I'll see how it works, new bearings were over $100 apiece from cat so I thought it'd be worth a try. I turned down the crank and polished it with three grades of emery then made the bearing .005 over that as this little motor doesn't have pressure lubrication .


----------



## dirty tools (Nov 14, 2014)

alum should be fine for the starter motor
pictures will help:nervous:


----------



## mce5802 (Nov 15, 2014)

Here we go....my quota was too low for pics I guess


----------



## mce5802 (Nov 15, 2014)

The k&t worked perfect for locating and drilling the oil hole which has a tube through it that keeps the bearing from turning. Cut a groove both ways from the hole with a chisel I ground from an old punch..quicker than setting it up in the shaper as the grooves don't go all the way across the bearing


----------



## davidh (Nov 16, 2014)

i don't know why it shouldn't work.  there are lots of small engines without inserts.  i did the same thing on a 5 hp compressor pump, i had to have the crank turned down and there were no undersized bearings to be had anywhere.  this was a rod bearing. . .
good job.


----------



## mce5802 (Nov 16, 2014)

Thanks. And yeah..I think even some later model car engines use aluminum rods without inserts. Guess we'll see.


----------



## bosephus (Nov 16, 2014)

nice job , quite a few of the cat pony engines had aluminum crank bearings from the factory .


----------



## mce5802 (Nov 16, 2014)

They did? Thats good to know. Should hold up good then as long as the alloys somewhat close to what they used. Thanks


----------

