AUTOPSY of a Caterpillar Pony Motor. | What Went Wrong? 

I have a feeling those mysterious gear teeth are from a previous catastrophic failure that wasn't cleared out before being replaced, or were left to make a speedy recovery in the field then forgotten about, before being parked.

Hey Matt - I worked for a large Caterpillar company in Denver, CO in the early 70’s. (I am 81, now). I worked on a lot of D8 Cats. We changed out the pony motor as an assembly and never got the chance to tear one apart. Very interesting.

Those teeth (my guess) are from a starter Bendix gear that was smashed from all that slop in the main bearings. Very interesting watching to dismantle something I'll probably never even see. Thank you Matt

Regarding the grey/silver sludge, I didn't see that anyone suggested it is actually LEAD from leaded gasoline. We used to call it grey paint. I was an apprentice car mechanic in the 60s when leaded gas was the norm. The grey paint would get so thick in the oil pan it would plug up the oil pickup. When removing an oil pan with that in it, it felt as heavy as if half a crankshaft was there. With the age of that pony engine, it likely ran most of its life with leaded gas.

I believe the teeth were from a failed starter bendix that never was retrieved when they had the initial starter problem Matt. The size and number is similar to the teeth count on the bendix.

BEFORE Diesel Creek I had NO idea what a pony moter was, and never even operated any piece of the sorts of equipment Matt is doing.(I'm a computer guy) NOW I own a tractor, bought a farm, and are fixing all sorts of duhdah's for whatever i need to get by, inspired by Matt and others like him. GREAT content !!

I will never, ever need to know any of what Matt tried to teach me today, but strange as that is I could not stop watching this. The flywheel slop was epic. These episodes are why you have 3/4 of a million subscribers.

After rebuilding starters and alternators for the last 40 years that appears to be the remnants of an opinion that came apart from a previously installed starter

a small gear like that, my guess is that it came from a broken starter that since have been replaced.

In all my years of rebuilding engines of all sizes, I've never came across one with that much wear that still ran. AMAZING! Thats why those old Cats just keep on going.

Fascinating teardown! The crankshaft bearings on these ponies are commonly ruined by a leaky carburetor valve: if the fuel shutoff isn't used and a tank of gas drains into the oil, the oil becomes useless. Just a short runtime with ruined oil will trash the crankshaft bearings.

From an expert ‘ole cat skinner’ who has gone to the dozer home in the sky: after you start the Diesel engine, disengage the pony, but don’t kill it. Turn off the gas and let it run dry. That warms up the pony, drains the carb, and your pony cast iron warms evenly to fight dampness. I pulled down my D7-3t pony and found a shop that could weld up and grind the crankshaft back to spec. We had to bore the cylinders off center to get them round again. My 3T was dry clutch so the previous owner managed to beat on the bendix with the canvas-and-sheet metal links that break in the dry clutch. I found bendix parts from a 2U in a junk yard. Be thankful for your oil clutch and be assured it could be worse.

Matt, at around the 10 minute mark you explain why you save old junk like this, but there's a neat side-effect of what you and those of use who care about old stuff do: there's a "gap" generation around old equipment where the old codgers who worked with it every day start to retire and pass on and the new kids in the field have new, high-tech fancy stuff and don't need things like pony motors &c., so off they go to collectors or the scrapper. With luck it's to a collector, and with greater luck still it's to a collector that will use it and instruct others in its use--like you're doing right now in this video. When these things pass out of every day use and into the "antique" world, there's a risk that they themselves as well as the understanding of their use is going to disappear forever. Think about steam engines, and how a whole generation of teachers were mostly lost before the nerds picked it back up again. All it takes is a generation of folks going "I don't know WTF that does" to lose that real-world, practical knowledge of the thing. Great example is live steam, which in the UK is SO MUCH more robust than here in North America. Why? The Brits took forever to switch from coal, we didn't. And that switch just so happened to coincide with folks starting to wake up and realize that it's worth saving the old stuff, even if it's not "useful" in a conventional sense anymore. Like a CAT pony motor. :) Thanks for giving a hoot about the old iron, Matt--preservation and conservation is a gift to future generations. There's always "a million of them" out there... until there isn't. Good, old machines deserve to be saved and ought to be put to work. They might be the only things that actually last in our age of emissions equipment and computer-controlled common-rail injection. Cheers, and I hope you and your pod have a happy Easter weekend. 🐇🐇🐇

Nice to see the work bench. Matt you outdid yourself again.

I had a cat12 grader with a 2 cyl boxer pony. Pony threw a rod, broke some pieces out of the bottom of one of the cylinders, so I left the bottom oil ring off on reassembly. CAT dealer didn't want to mess with it which they told me by offering a ridiculous amount of $$$ to even look at it. Also got into a contention between CAT and auto shop as to who broke the end housing getting it off the crank, but CAT made it good with another from their boneyard. New pistons, rings, rods and bearings and it ran like new. Thank goodness for their boneyard, I also needed a steering knuckle for that machine. Apparently it's common for the spindle to fatigue crack, because mine cracked through, and the first one they got me was also cracked in the same place. The first spindle failed a bright early new year's morning, then broke the spindle on my case 580B trying to get the CAT12 off the runway, all before noon. Which goes to show you don't do ANYTHING before eating your black-eyed peas New Year's morning!

That gearbox case looks like an ideal candidate for you to practice cold stitching on. Check out the guys from Tinkering with Tanks and see them repair a cast iron block. You never know when you might come across a really rare engine that you can't just swap out casings on. Love the content Matt

The gear teeth look like they may have come from an old starter Bendix that might have dynamited at some time. Most likely from the flywheel being as it is. Amazing that this engine still cranked over. Love the old iron, they are almost indestructible. No engineered obsolescence.

What I love about this channel is how you always steam clean or pressure wash an item before you start to video. That removes the blackened grease/oil sludge from the working surface and allows much better video content.

My take away from watching this is pure amazement with the engineers who designed and manufactured that whole assembly pre computers. I can't imagine the cost to make all the tooling to cast all those different pieces in an economical way. Mind blowing to me.

It's the wizbanger gear connected to knuten slide shaft. Really look at side of the gears.

Wouldn't be hard to braze up that gear case. Worth saving. Doesn't have to be difficult. Prep the weld seem. It doesn't have to be huge. A 3/16 v is enough. Drill holes at each end of the crack. Build a nice big wood fire and get it all hot in some coals. Keep it in the coals while you heat up the joint and braze it up. Finnish by building up the fire a bit to bring it all up to an even heat. Cover it all with the coals and ashes when it dies down so it cools slow. Leave it till the next day. It sounds like a lot, but really isn't. Most of the effort is building a bonfire and watching it burn.

I own a tree service company and am from the city so naturally without much mechanical knowledge I would just send my trucks and machines to my mechanic, after watching your videos for the past year I always try taking a crack at it myself now, saved myself so much money and have learned so so much from your channel, thanks for the awesome content Matt, love and respect from southern Ontario, Canada!

Love how you can drop a pony on your ‘new’ bench with a forklift and it doesn’t even flinch 👍

You had me at autopsy of a pony motor. I have always wondered what the inside of one looks like. Very interesting. I agree, definitely keep any parts usable though.

I'm so glad you posted a video today, because the 10th. of this month I was on my death bed, but I barely pulled through and it seems that each day now is a Blessing, but I'm still very weak and very limited mobility from this awful Flu I caught from my Grandson that he got at the Daycare. I hope I get to see more of your videos .

I agree with the mystery teeth coming from a previous starter catastrophic failure. I have never been in a position where my (and possibly my family's) next meal depended on me getting a piece of equipment operating so I could finish a job and get paid. The pressures of life and the mindset of someone who doesn't perform recommended oil changes and would also leave gear teeth inside a gear case is something I cannot relate to in any way. Matt has clearly established that neither the motor or the gear case received recommended maintenance and that the carnage occurred because of the wear on the engine main bearings which was due to oil that was filled with abrasive particles. Maintenance is not done for various reasons. I know/have known people that can always find money for beer and smokes but can never find money for oil changes. If every machine owner put maintenance high on the list of important things Matt wouldn't have a channel. Without so many mistreated machines we wouldn't have such entertaining videos illustrating the effects of that mistreatment.

Have a beautiful Easter everyone!.

Try to take the crank to machine shop what they say. Try to turn it. The bearings you can pour yourself -> functional engine. The transmission - you can try to bronze weld it. It was quite often used technique in 50 and 60 when engine block cracked. Such a block was used for very long time afterwards. If you never made it this transmission is perfect thing for a try and learn.

That gear case is repairable actually, if it is made of cast steel it will be easier to weld than if it is made of cast iron, but even cast iron is weldable if it is heavily pre heated to a couple of hundred degree's first and then covered and allowed to cool very slowly after welding. Years and years ago when I first started in the trade it was an accepted part of the job and we refurbished many a block / gearbox casing/ and rear axle this way, that block is also repairable in the same manner, weld up the webs on the crank and have them turned back to spec by a crank grinder and do the same for any out of spec rotating surfaces and the rebuilt engine will be as good as new........important since as you said they are getting rarer than hens teeth now........there will come a day there wont be anymore left at all and you will be glad you didnt bin it. once they are gone there isnt any way back.

20:16 Look at the flywheel teeth. That's where the "gravel" comes from. Thanks for sharing !

That pony motor was rebuilt 5 months before I was born. My parternal Grandfather ran those Cats back then, but in the other side of the country. He was about my age then too.😊

Matt that was amazing. I’ve known of pony motors but to watch you disassemble it to diagnose the issue opened my eyes to them. I’m more familiar with pony motors on two cylinder diesel John Deere’s.

loosely assemble it back in the case for storage, protects and takes up less space than all the bits spread out.

I went to Ferris State College (university now) for heavy equipment service. Myself and two other guys got to do a complete rebuild on one of those Cat pony motors at the college. Those little brutes were quite a marvel. Heavy as can be and even 44 years ago parts were expensive and hard to get. But, we got er done and she ran great. The school also had a top notch automotive machine shop program so machining a crank was easy to get done.

"new" forklift??? Did I miss that video? 🤔🤔🤔

Compare the shrapnel gear to a starter Bendix gear. At some point in its life it may have had an Old exploded starter from the crank bouncing around, The starter being replaced and you running it long enough to free the parts up from the sludge.

Drill both ends of crack with oh 5/16 drill bit. Then preheat case to 450 then weld with nickel rod then but case right back in oven still on 450 then over hours slowly bring temp down slow slow if to fast it will crack

I am an IT guy from Germany. So I could not be further removed from this topic, but yet still I love watching these videos. Keep up the good work of reviving old steel that others have left to die. Also very nice to see your channel frow over the years, almost at the 1 million mark now, great :D

You need to have that workshop crane installed. Look forward for the video 🙂

Love the baby T-Rex shadow on the work bench around 10min mark

Semi SuperVillans knock it out of the park with their music !! LOVE the opening music!!

Now it's nice and clean it seems a shame not to rebuild it. Use those gear teeth to cast a new cog and a bit of gaffer tape around the crack on that housing, and grease up those bearings. It'll be good as new.

Nice morning, Coffee and Diesel Creek with Matt.

23.56 that looks like a hand cast babbit barring not a insert. i had to learn how to cast babbit baring in old mining equipment. It can be fun. sometimes in remote areas old repairman could not get barring inserts and would pour their own babbit barrings as replacements.

I hope you have at least some experience of "hand cranking" engines ! The use of the starting handle is probably the first introduction to the workings of the motor car, that those of us born in the fifties had ! I got my practice in, on my father's Rover 14, in the " here, you have a go !" basis. Later I found that 4 cylinder motor motors were easier. In my twenties I was still at it with decrepit small lorries on building sites,and dump trucks etc. If you are not used to hand starting motors you have missed out on learning how to wheeze and cough properly, such fun...

Somehow I saw the auction video before the new forklift appearance. Love it all. Label the parts bin before it’s confused with other parts: pony parts. 😅

The gearbox assembly is toast, but what about doing a full rebuild on the motor unit? What about a colab with the other awesome RU-vid JimsAutomotiveMachineShop? Would be amazing to see that motor brought back to fresh!

Matt , the time and investment in your super heavy duty work bench sure has paid off! It handles the weight of that Pony motor like it was nothing at all.

Matt like the video man .

I have a difficult time imagining how the heck the design engineers come up with the designs to make these things work together.

It's pretty awesome when you find metal that's the consistency and texture of CLAY under a gasket.. WOW 16:10

I had to re -shoe a caterpillar pony once , so many legs by the time i finished I had to start again 😅🍻

I would've pressure washed the whole thing before starting. Great content! I liked the variety vs the other videos (which already have good variety.)

Thank you for putting the diesel creek sound track back on

I’m thinking those teeth are remains of an old starter or gear that failed at some point and was replaced. Just shrapnel that was left behind. 🤷‍♂️ I sure do enjoy watching these videos and appreciate you bringing us along. Thanks Matt.

Good times. Lunchtime in the UK with Diesel Creek. Epic.

Electric start donkey (pony) engine,? oh the luxury ! I would miss the workout of the starting handle and the danger of having your teeth knocked out when it kicks back. Love these videos so much. thanks

Nice way to showcase all your new toys! I have been watching for years. Happy for your success. Thanks for the in depth view of the pony motor starter system.

Really glad you took the time to post this video. I'm in the process of trying to save an old Cat D7 cable dozer with a pony motor from the scrap yard. It's a long shot since it's been sitting 20+ years. Getting the pony running is going to be a challenge.

Love the New Intro Matt 0:02 Freaking Awesome @Diesel Creek

Thanks for sharing. In a have-to situation the case is repairable. It can be drilled and pinned, etc. But, I couldn't do it. Ron PTL USA

When you hear the intro music you know you're in a good place!!

19:56 Auh, did this engine run? WoW!

That babbitt bearing was probably a poured lead job which would explain why the metal in the bottom of the pan is so fine.

30 seconds in and i approve of this intro over the honking rigs... this is far better!

Great video as always love the sound track ❤👍🏻great watch on a Easter Sunday afternoon here in the uk 🇬🇧 keep them coming, Happy Easter Matt and everyone else 🙂👍🏻🇬🇧

That snap on hi vis is the proper color

Hell yeah Matt, keep this stuff going , keep all that's salvageable , these analogue pieces are important, all this digital controlled crap is expensive and complicated to fix. Analogue can be fixed by anyone with tools , brains and experience

I can't help with the mystery gear teeth. But the new forklift...? There is a video there, I think!

It’s a amazing how cluttered the new massive shop is now! Soon it’ll be filled like his garage at the house! Time to build another shop Matt and get that one filled up. LOL LOL

This is my go-to channel alongside Marty-T from New Zealand, Ants Pants from Estonia and Kris Harbor Natural Building from GB. Aways makes my day when these guys are dropping new content.

Old things are great, repair as long as possible and when no longer possible to repair, strip off every reusable part to keep other old things working.

Mystery teeth could be off an old starter that's since been replaced. Just never got cleaned up...

I miss the Saturday videos, became a ritual for a while. BUT, YOU do what works for YOU! You're a busy man. I'm going to watch the videos no matter WHEN you post them!!!

Look at you, in your big new shop, boing big shop things. ATTA-BOY

RIP Pony. Congratulations on 3/4 million subs Matt.

You know the old engineer saying: "Everything was fine until it exploded." 😁😁🤘🤘

While we missed the "new forklift" vid, we can agree this teardown was well worth the wait! Great work, Matt.

Hi Matt, the gear pieces were probably shattered starter motor pinion gear/s 😊

DC: sees silver paste "oh, its probably ok" Every Mechanic on the Planet: nope, nope she's pretty well screwed.

One thing I came across on an old firetruck I had to repair was the bendix housing was to thick. Because it was no the bendix teeth to fully engage the flywheel.

Wild guess s those teeth were from a part that was replaced? Something stripped the teeth off, maybe the starter? They replaced the starter but didn't pull the whole thing open to gett he bad parts out

Hello Matt, I was going with the end of an old starter as well. Enjoy the videos over here in France. Keep doing what you're doing. Thanks.

morning all you DC boyz got your coffee?

I'm confident I could repair that gear case if you really want to retain it for originality, I'd be happy to do it.

SHEPPARTON AUSTRALIA LOVES DC

Really like these engine disassembly...

Diesel Creek and breakfast, a perfect combination😁 Happy Easter Matt.

Cheers for the content and ur merch is top notch ordered the t shirts 8 days ago from Scotland where i stay and they arrived today april 2 2024 great delivery time for a overseas delivery thank you again

An old feller told me once that those ole starting engines were basically half of a Cat Ten or Fifteen engine can’t remember which one, but if there is any truth to it you might find internal engine parts there too.

Back from the mid '60's when I became an apprentice mechanic, through to the end of the '70's, I worked on everything from lawnmowers to Cat D9 Bulldozers. The main dozer in the fleet at the time was the D8E. These were the four cylinder models with petrol engine start. We called then Donkey motors. The one I loved more than the others was one tractor that had a right angle drive for a hand crank start of the Donkey engine. At one time the operator boasted that he could hand start his D8E, in the snow, Sure enough, he knew his business & hand cranked his Donkey motor to life & let it run while he slowly rolled a smoke & lit it. He then pulled it into low gear & engaged the flywheel, then went to make a cup of tea. Next, change into high gear & let the engine turn over while enjoying a 'cuppa'. & a smoke. After a time he mounted his steed, & started it up in the usual way, fulfilling his boast. None of the others in the fleet had this hand crank feature, but those D8's worked & worked & never ever really let us down. [Except the one that slid sideways off the trailer & bent the blade.] That was about fifty years ago. Greetings from Australia.

the flywheel is likely heavy so that you have some amount of rotating mass and stored energy so the pony motor doesn't just stall but instead has some store energy.

Definitely Saving as many parts as possible Rich Good Video

Matt Squatch253 is the place to learn about these. Glad to see you saving these parts.

Those gear tooth are from another starter they put on the pone motor diesel

Man I love that intro music by the The Semi Supervillains ✌️

1:23 Is that a new forklift?

Great vid...but i hope you didnt ditch the ol allis forklift! Love the old iron still working

“The initials PC….that’s Pretty Cool” 😂

Hey Matt . . . isn't it the case that Quaker State was known to characteristically leave a bunch of grey-ish sludge behind due to its higher paraffin content. Yes, I well aware that QS is a very different product NOW when compared to their oils 30 years ago, but my personal experience came from using it (for a while) in my wonderful old '67 VW back in college, and grey sludge was always present when using QS until I switched to Valvoline which never left any kind of similar residue on the oil plate. I believe the paraffin combined with moisture that might accumulate in the crankcase when the car was run for shorter distances and not run long enough for the engine to completely warm up - "short" runs like this were the norm when running from my dorm to any class anywhere on campus. Anyway - love your thoughtful and entertaining content. I always learn something. Thanks for doing what you do the way you do it. Best to you, Matt