1950 D4 7U. Stuck engine options.

Caterpillar has most, if not all, the gaskets, but if any are not available, your options include new old stock from various vendors on machinery trader.com, and Olson's Gaskets. You need the correct parts catalog for your serial #. The catalogs cover a range of serial #s so make sure yours is included. Also get the serviceman's manual

The D320 is more of a sooped up version of the D311 4" bore engine. Later version too......injection pump is on opposite side of the engine It could be done but easier and probably cheaper to fix the D315 4.5" bore engine. Displacement is king!

Thanks, for the info.

I will get a better idea probably this weekend on how bad, how much rust in the cylinder.

Will get a chance to yank out the injectors and use my scope to see how bad it is!

So finally had a chance to work on it.
Lubed it up and got it turning over. Just a small amount of rust in the cylinder.
Problem now is the pony motor, runs but leaks oil into the flywheel housing and loose mains on the crank.
Vertical movement of the flywheel/starter pulley.

Question. What is the cost to rebuild? Or would be better to go electric start at this time?

Doesn't have the starter boss, but was considering the top mount starter from b and c. Good and bad?

Unit needs track chains, and tensioner work best place to get pieces. Has 1/2 shoe bolts so probably semi original tracks.

Some wear in the frame where the front track idler sits, some play in the roller!!

Any info or assistance would be great to find parts and pieces.

I don't know if it would be cheaper to go electric start, even figuring in the price of a new starter motor, two batteries, wiring and switches. To grind the pony crank and fit undersize bearings is probably 300-500 depending on where you go. I've just done two ponies and if I total just that work, that's the estimate for a grind, bearings, seals, and gaskets. (I always do a lot more than the bare minimum but you don't need to). A new starter and nose assembly can be figured from ebay plus a pair of new batteries (those are min. 100 ea) I'd say it might be a wash. Advantage of electric start is that there's little to go wrong - flat batteries is about it, and all you need to do to start is push the button. Advantage of pony is that it'll get your main engine going even if the main is in bad shape and you don't have to have batteries to get stolen. If you already have the electric start hole in the flywheel housing, then it's pretty easy to bolt on the electric start parts. You can have both too - pony and electric start.

A 1950 crawler will need the starter hole drilled. I believe power units had it drilled with a cover

Neil read post 6 more carefully. He said mount it on top. I have heard of a conversion that mounts in place of the pony motor an uses the same gears the pony used. So my guess is this is what Mustangh68 is meaning.


Other than the person that told had no comment about how good it worked or lasted. This person is no longer around to ask,but I think I know where the said D4 and D6 are but not sure.

ah yes thanks for pointing that out Ray. I have no experience with that setup