D2 pony motor carnage

Just picked up a new to me D2 5J10217. Auction caption was "pony motor wont turn over completely". So the kids and I won the auction, loaded up the tools to see if we could.....free up the pinion....maybe a lil rust ring in the cylinder that needed some love.....stuck valve....any of the myriad of things that may prevent it free turning 360°. Along comes an auction worker that says, "Dont bother wrenchin' on her! I had her screaming the other day and she locked up good!". Didnt bother mentioning that in our hour discussion on viewing day......

On the upside, the deceased former owners daughter had a fistful of books and manuals to go with it. Including receipts as far back as 1969. Looks like the pony was rebuilt in '71 and the main engine in '86 ( when the crank was ground .030 under) and again in '02. Unfortunately, there was also a quote for rebuild parts again in 2010, but no receipt that they were actually purchased. The hour meter isnt even in the housing so no guess on the hours, but as an added bonus, the track chains measure just barely shy of 3" so they are next to brand new! (According to what Ive read, you gentlemen would know better than I) And so the yellow fever begins, as you can see the D7 17A in the background. The bottom of the block is cracked pretty good, but is it beyond repair? The rest of the block is in really good shape, and the crank appears to have weathered the storm pretty well. A gentleman from Colton, OR left his number on a tag on the machine, didnt catch his screen name on here when we talked on the phone, but he says he has a yard full of parts machines so I should be on my way to pushin dirt fairly soon.

Ha! "had her screamin" dont they all? I'd take that rod and piston and wack him on the head with it! Some idiots can destroy an anvil with a rubber mallet!

Lots of mental pygmies out there. If only the oil was checked might be pushing dirt sooner.

Fortunately, there are a lot of parts available from Caterpillar and others for pony motors.

Squatch253 on YouTube is about to start a pony rebuild series and while not as detailed as his
videos usually are, I did a series of videos on my pony rebuild last year on my YT LineshaftRestorations channel.

I wonder what the bent rod was from. High RPMs and fuel in the oil?
Ugly for sure, I’m guessing as long as nothing else broken, I.e. crankshaft, it wouldn’t be too bad dollar wise. I would not be happy, not knowing they grenaded it after they listed it for sale.
Thankful that our own “local” auction company encourages the skilled hands of some well seasoned farmers to do their start ups and demonstrations. They’re the ones that have forgotten more than I’ll ever learn!
Good luck on your new toy. Show us pics and videos too! JM

Now that I've got it all torn down and cleaned up, I'm guessing that the cotter pin of the rod nut fell out. Which in turn let the nut back off, then the loose bearing got chewed up, which led to the blue heat marks on the rod. Looks like the rod bolt must've popped out and a few revolutions later the cap finally broke and KER-PLOW!!! I had 2 pristine small cotter pins on the bottom, as well as an unmarred rod nut. How has anyone's experience been with repaired (welded) blocks? I can melt steel just fine, but this calls for a professional. Surprisingly, most of the other surfaces measured out fairly well. The cam is just barely out of spec. About .001 under limits. Not sure how picky to be when parts can be scarce. Any advice on that, gentlemen? And even the chowdered rod journal looks like it can be cleaned up by going .030 under. Everything is already .020 under.

Lineshaft Restoration, yourself and Squatch253 make awesome tractor porn!!! I could watch both of you all day! None of your videos will go unwatched by me.