Pony motor (donkey start) disassembly 1939 Caterpillar D4 'Lil Lefty' 4G9986 Episode #54

Let's open up the pony motor and see how it looks! Our hopes are high with this one! Overall, progress continues on the 1939 Cat D4 agricultural crawler. 4G9986 "Lil Lefty" has never been so much fun and fulfilling. I hope you enjoy the shop talk, banter and commentary.

Thanks for watching!

Regards,
Aaron & Greg "The cleaner"

LAOL
P.O. Box 395
Keenesburg, CO 80643

Episode #54

#caterpillar #tractors #colorado #family #corel #mechanic #diesel #history #repair #rebuild #agraculture #gopro #dozer #colorado #engine

Used gopro and corel editing software in the creation of this video.

[michaelhalfman]

Famous last words, "we're this far and there are only a few more bolts."

[dwjr]

I know you guys know this but for those who might not, Squatch253 has an in-depth series on pony motors. He’s like the professor of pony motors!

[bigredc]

Good catch.
Definitely the right move to go over the hole motor.

[Thomas-bvmn]

Nice to see all the insides of what I have not taken apart. I have my Dads old D4 7U he bought new in 1953.

[stevenross]

My situation with a D6 Pony was a Hydraulic-lock due to all the openings for the coolant being plugged. My reaction was the same, looked like mud. The small drain valve was not able to release any liquids.

[TomTeater]

You guys are a hoot to watch, thank You!

[markeardley]

I just finished rebiulding my D2 pilot motor, except vales everything is still available. There was a huge wait on new rod nuts so i had to reuse mine.
New os pistons and rings are available here in Australia.
And use the marks on the gears when re installing the mag. I had issues with the way the book described it.
Keep up the good work mates.

[johnkaijankoski]

I’ve heated used copper head gaskets with a torch to anneal them so they’re soft again and have reused them without a problem. Copper gets hard with heat and vibration. Cat has all the gaskets and seals needed to rebuild the pony engines. Plus bearings and rings.

[waynep]

Speedometer cable core cut to different lengths in a variable speed drill really cleans out tight passages

[timcope]

Use copper coat on those head gaskets and the intake and you can reuse both. Not silicone.

[joelhart]

I think you should give it a quick hone and put new rings it is standard

[PacificNorthwestHillbilly]

Doesn't harbor freight carry those pony motors???

[SuperMAZ]

Catching that valve pack like a pro. What I would do is take critical measurements of the surfaces that need rework and then decide how much to hone or polish. So far I don't see anything that would indicate catastrophic failures or misuse over the years. Not uncommon that all the dirt and debris gets stuck usually at the last two liners or the starting engine. That also causes overheat issues later, cause you might have no idea that the ports or liner is plugged full of rust and debris.

[carbie]

Nice Job, it sure is nice to learn about this stuff without having to read and decipher what I read. I am reading about my 1960 or 1961 Case Loader Backhoe I just got. Actually, I believe it to be a 540 as it is gas. I have a Service manual an Operators manual and a Parts manual. What a pain it is trying to find something out and having to switch back and forth because whatever I am looking for is not in the book I think it should be in. Parts books are nice to have also. On my D4 I do not have the operator's manual, so I need to still get that one. I was looking at the hydraulic pump in the Parts book and then I looked at the pump in the shop manual and finally realized I was not looking at the pump I wanted to look at. I was looking for the hydraulic pump for the loader and backhoe, not the pump for the pto, which I do not think is in this as it is a Backhoe. Plus, there isn't a serial number on the tractor but there is one on the Loader and Backhoe and they are models 31. I have really been working on understanding these books and this Backhoe. The wiring in it is all messed up along with a lot of other things. I did not think at all about it being a positive ground until I saw the wiring diagram. Now I need to make sure someone did not convert it or try to convert it or put the battery in as negative ground and ruin something. But it is still fun figuring it out, to bad I need it now. lol Oh well what is time but to just enjoy what you are doing and the heck with everything else.

[SocalMarineUSA]

fantastic vid! my pony just locked up today - i thought it could be a stuck valve but wouldnt u know it the geniuses have the valves inline with the piston which eliminates that. Not quite sure but judging from yours be good to pop my heads off too - i think some copper spray would be ok and leave the shim head gasket on there- the head doesnt really do much than seal combustion pressures, flow coolant and holt the spark plug. Glad u have such good detailed videos up so I dont have to lol

[keithwarkentin]

Well I really hate being that guy but I couldn’t help but notice that you and the Cleaner were not wearing your hard hats in a hard hat area!!
And furthermore a Johndeere hat while working on a Cat I don’t know!!
But seriously that valve train system is almost identical to an 8N Ford! I thought that looks awful familiar good thing you decided to open her up because that water jacket needs to be perfectly clean so it doesn’t get hot because I bet that 2 cylinder works pretty hard when it’s employed and I can’t wait to see what the rod journals will look like 😀🇨🇦

[colin]

Looks like you ended up with a real nice 666 devil block! Squatch would like to have that one I bet

[duginvirginia]

Excellent work as always. Totally unrealted, where did you find the red plastic / rubber parts tray with the metal tray insert that's on your workbench?

[ruben_balea]

The only good thing about taking things apart without looking at the book is that if you break something you still have a really cheap excuse, you can even say you've learned something for next time, but if you break it while following the instructions you can end up pretty upset with yourself 🤦‍♂

[andrewklahold]

Whole new tractor !!!! I guess that would work in your riding mower