D6 pony motor

[chickensoup]

Anyone out there have any hands on expierience with cat pony motors? I'm assembling one for a D6, I've bought new main bearings and when I install them with the oil holes and dowel pin holes lined up I have excessive crankshaft end play.
 

[gemdozer]

If you bought standar bearing maybe you need .020 or .o30 you need to check your main crankshaft size.
 

[chickensoup]

End play, not journal to bearing clearance.
 

[WayneB]

Interested in a complete D-6 Pony? I converted to electric. Pulled mine, with good compression, new rebuilt carb and magneto and new gas tank & lines. On a pallet in my shop.

Wayne in Virginia
 

[gemdozer]

You di't forget to reinstaled the big washer (4b2293) on rear or the washer was he to worn tickness
 

[chickensoup]

I definately would be if I had'nt bought the parts! Does the electric start conversion work good?
 

[chickensoup]

I hav'nt got to that washer yet. As I said when I line up the oil holes and dowel hole the clearence is excessive. I can drive the bearing in further and take up the clearence, but then my holes are not aligned. I only have a parts manual, according to that all bearing numbers for several serial numbers are the same.
 

[dieseldr]

Is this one you had and tore down, or one that someone brought you, or one you never heard run before? What I'm getting at is if someone ground the thrust faces on the crank to an excessive amount to cause excessive end play.... hard telling what others have done before you got there. Most pony engines I was ever around seemed to have end play measured in inches instead of thousandths. Just my experience.
 

[Old Magnet]

The washer butts up against the bearing to control the thrust on one direction. The crankshaft butts up against the other bearing to control the thrust in the other direction

If the crankshaft thrust face is in good condition the bearing can be moved and the dowel pin and lube holes can be redrilled using the housing as a guide. Drill 15/64 and ream to 0,249-0.250 for the dowel.

Thrust should be 0.010 to 0.016
Max allowable is 0.025.

Another option is to make an all new bearing out of T6 aluminum that fits the conditions.
Crankshafts can also be built up to restore original clearances and fit original bearing specs.
 

[chickensoup]

Thank you oldmagnet, my thought was to drill the bearing, just thought I would ask a couple questions before doing that. Seems remotely crude, but if thats cat procedure then I will. Thanks again.
 

[chickensoup]

Long story, the engine came to me in a box in pieces. Yes, it had obviously been tampered with. I inspected the crank very closely, did'nt appear to have any prior work done. The bearing did though. Thats why I bought new bearings from cat, just trying to get as close to original spec as possible. The engine on the machine has very little end ply, but a cracked block.
 

[WayneB]

Electric start works great. The speed that my starter turns the engine is surprisingly fast. For where I live in South Central Virgina I will have little problems with the extreme cold temperatures that concern some when thinking of conversion from Pup to electric. For me it was a good choice.
Wayne
 

[NCWayne]

What motor is the pony going on? Next week I'll be working out of town for a customer that had a factory service manual for the D333 thats in his old D6. I used it last year when I rebuilt the main engine for him and I believe it also has all of the pony motor stuff in it too. If you need something out of it just let me know, and I'll see if he'll let me bum it off of him for a day or so while I'm town.
 

[Old Magnet]

The drill and ream procedure is the Cat method for original fitting parts. The moving and redrilling is a make do.
 

[chickensoup]

I see, as long as it works I'll do what I have to. Seems I had to move the bearing in quite alot though, I did'nt actually measure it, but I bet it was close to a quarter inch. Why so far off with original cat parts? I have no known history of this engine so I suppose it could be a mix and match from years past.