D2 and D4 Pony end solution

We all know that the bearing's from the pony engine are a weak spot.
The 10 pony's i did rebuild had all the same problem, endplay or completely worn out bearings and crank coused by losing the bearing dowel.

Before the forum changed, i found a post from Uncle Rich, he added 2 bronze trust washer's to take out the end play to stabelise the crank. 
A few weeks ago i went searching for his post's put i could not find them any more, the links's were not working anymore.
But after searching with google i found the right link to the article's 
https://www.acmoc.org/bb/discussion-d72/14147-d-2-starting-motor-crankshaft-endplay?start=0
https://www.acmoc.org/bb/discussion-d72/10550-d2-pony-crankshaft-thrust-bearings

From both articles i could take the info needed and i did order the trust washers here: https://www.motion.com/products/sku/03084315

After measuring the end play, we could make a plan how to do it. The play should be 0.020 to 0.025, we measured 0.050 so that was a bit to much! 

The washers are 1/8 inch thick so we started calculating what to do. 
Last given thing is that the play is made by the dowel that comes lose, and the rear bearing that eats away. 
So the decision was made to take the thickness of the washer off from the font bearing, and adjust the play with taking more or less from the back bearing. 

1/8 inch is 0.125,                       = 3.17 mm (milimeter)  washer thickness 
0.050 inch                                 = 1.27 mm end play
0.020 inch                                 = 0.5 mm wanted end play 
0.050 - 0.020 = 0.030 inch       =  0.77 mm Actual end play minus the wanted end play.

So we took 0.125 inch (3.17 mm) from the front bearing.And 0.125 - 0.03 = 0.095 inch (2.41 mm) from the back bearing. 

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As Uncle rich explained is the ID size a bit to narrow, But thats not a problem we turned them a bit wider, and added a 45 face so the washer is faling over the ridge on the crank. 

This is the result:     


We measured the end play and it gave us 0.020 inch of play so that was what we wanted! Today i reassembled the pony and we did a little test run, she is running smoothly and there is no problem any more with the flywheel riding in and out!

More pictures in the reply, 

Thanks Niels   
 

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Very nice work there Nielske, thankyou for taking the time to share that repair, and finding the original thread from Uncle Rich, you did well to dig that out of the ethernet from so long ago! Finding new main and conrod bearings for those pilot motors will be the challenge we all face going forward, particularly in undersize dimensions, I've rebuilt 2 pony motors with the expert help of Eddie Bedwell, and if it wasn't for Florin Tractor Parts back then, I would have been unsuccessful finding crankshaft bearings, because Cat don't supply too many options, and now Florin is closed.

Maybe someone here will start machining some up, I was told by a Metallurgist years ago, who worked for Toyota, and had tested those Cat pony motor crank bearings, that the alloy used was almost identical to the alloy used by Toyota to make their pistons, he suggested getting some old Toyota pistons from a car wrecker and melting them down, to create new bearing shells, apparently the alloy has a high % of tin, for hardness.

Good deal Nielske, I made the same update to my 3J pony about 8 years ago and to the 5U's pony about 4 years ago and in both cases, I've been very happy with the result. My end-float turned out to be 015. It's a pretty easy update to make if you are, or have access to a machinist. As always, it's a matter of measuring accurately : )

Great work!!

yes tame machinists come in very handy. especially if they work for beer money. though beer aint that cheap anymore.

While we are here, how much does a D2/D4 pony motor weigh?
Calculating shipping logistics.
(Asked by the guy who hauled a flathead Ford V8 engine from Idaho to California in the back of his diesel rabbit circa 1987)

about 60kg or so there not exactly light.