1965 Thiokol 601 Budget Restoration/Resurrection

PradoTDI

Member
Hello everyone! New snowcat owner here. I've been looking for one for several years, narrowly missed buying a Tucker 442 for $1500 last year.

A couple of weeks ago I was browsing through the local Craigslist and came across a listing showing a Thiokol for $500. I sent a text and the next day made the 2hr trip to go take a look. The cat had been sitting under a tree deep in the NW Montana woods for at least 15 years, and was home to some mice and a few thousand ants. I sealed the deal and was back the next morning with a truck and trailer.
 

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PradoTDI

Member
One interesting thing I noticed is that there are two different data tags; the one on the engine cover doesn't match the one riveted to the body. I can only assume that at some point the original engine cover was either destroyed or lost, and a different one was sourced.
 

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Cidertom

Chionophile
GOLD Site Supporter
Welcome to the insanity.



As you start cleanup, I urge you to be very careful about the mouse problem. Hantavirus can be very serious. vacuum and mask, not sweep, and have the vac discharge away from you.



Looks to be a good project.


have fun
 

m1west

Well-known member
GOLD Site Supporter
I had a 603 that had sat for some time, I will be surprised if the grousers that have been on the ground are any good. I had to repair/ replace quite a few. It performed very well and is not a snow only machine, it will handle off road terrain. The only down side was it was difficult to steer and even in the winter it was very hot inside. fuel economy was about 4mpg, out of all the snow cats it goes pretty fast 28 mph but felt floaty and sketchy at a high speed to me. You got it for a good price, Have fun with your project
 

sno-drifter

Bronze Member
GOLD Site Supporter
Welcome to the insanity.



As you start cleanup, I urge you to be very careful about the mouse problem. Hantavirus can be very serious. vacuum and mask, not sweep, and have the vac discharge away from you.



Looks to be a good project.


have fun
What Tom said is for real. Hantavirus could very well be your entry to Coronavirus.
Check the ser. no. on the engine to see if it matches the military brass plate to see if that's the real ID. Looks like one is a 601 and one 602. ser. nos. different too.
 

PradoTDI

Member
Welcome to the insanity.



As you start cleanup, I urge you to be very careful about the mouse problem. Hantavirus can be very serious. vacuum and mask, not sweep, and have the vac discharge away from you.



Looks to be a good project.


have fun

Absolutely! With a 38% death rate I take hantavirus very seriously. The rear seat bottoms have already found their way to the landfill, and the back half of the cat has been washed out with a hose and scrub brush. Still have the front half to do, and am planning on media blasting the whole interior.
 

PradoTDI

Member
We had to take the tracks off to fit it on our trailer, I will have to either find a new trailer or make some ramps someday.

Once we got home we broke out the pressure washer and started cleaning up 15 years worth of grime and dirt. Quite a bit of the paint came off as well, which is a plus for me since it was a pretty wretched rattle can job that had faded considerably. The plan at this point is to take the body to bare aluminum and leave it that way, at least until I can spare money for luxuries like paint!
 

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PradoTDI

Member
I had a 603 that had sat for some time, I will be surprised if the grousers that have been on the ground are any good. I had to repair/ replace quite a few. It performed very well and is not a snow only machine, it will handle off road terrain. The only down side was it was difficult to steer and even in the winter it was very hot inside. fuel economy was about 4mpg, out of all the snow cats it goes pretty fast 28 mph but felt floaty and sketchy at a high speed to me. You got it for a good price, Have fun with your project

As you predicted, most of the grousers are in very poor shape; many are worn through on the tops or rusted through on the bottoms or sides. A few show cracks where the bends are. I am planning on replacing all of them, I have already been working on designing a new die for my tubing bender to make the tight radius bends in 1 1/4" square tube. I've calculated that it will take about 28 20' sticks of square tube, as well as 10+ each of the flat bar and half oval. Thinking about running a couple of beads of hard surfacing across the top of each grouser for longevity, but will cross that bridge when I come to it. Most of the rubber belting looks pretty poor as well, so that will probably all get replaced.
 

m1west

Well-known member
GOLD Site Supporter
As you predicted, most of the grousers are in very poor shape; many are worn through on the tops or rusted through on the bottoms or sides. A few show cracks where the bends are. I am planning on replacing all of them, I have already been working on designing a new die for my tubing bender to make the tight radius bends in 1 1/4" square tube. I've calculated that it will take about 28 20' sticks of square tube, as well as 10+ each of the flat bar and half oval. Thinking about running a couple of beads of hard surfacing across the top of each grouser for longevity, but will cross that bridge when I come to it. Most of the rubber belting looks pretty poor as well, so that will probably all get replaced.

Some folks make the entire drop section of the grouser where the tire rides from solid stock by having them water jetted or plasma then just weld on your pre drilled tubes on the end and your done and they won't ware out or rust out again.
If I remember correctly Minnesota outdoors that advertises and posts here had some for sale.
 

PradoTDI

Member
That's a great idea about the solid drop centers for the grousers, I'll have to check with MN Outdoors and get some pricing. If I can fit them into the budget great, otherwise I'll have to do a lot more work! Here is the grouser bar and bending die I drew in cad, looks like they have 2" centerline radius bends from what I could measure.
 

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m1west

Well-known member
GOLD Site Supporter
That's a great idea about the solid drop centers for the grousers, I'll have to check with MN Outdoors and get some pricing. If I can fit them into the budget great, otherwise I'll have to do a lot more work! Here is the grouser bar and bending die I drew in cad, looks like they have 2" centerline radius bends from what I could measure.

Thats the way it works, time is money. If you decide to bend them, if they kink you can fill them with sand, it helps with collapsing in the middle. Looks like its cleaning up nicely. If it was running when parked the tracks are likely to be your biggest challenge. Have you taken the cover off of the differential or checked the oil yet? If no water got in there you're in pretty good shape. The only other issue had with mine is it vapor locked when I got it, likely due to all the heat in the engine bay and the crappy gas they sell now days. I was able to work through it. Play your cards right and you could be on the snow this winter.
 

Snowy Rivers

Well-known member
Definitely check the oil in the diffy.

Drain it all and refill....

If you find water then you need to get inside that sucker and check things out.

My differential had a lot of water in it.....and there is a lot of work yet to clean that mess up.

A tiny drizzle in the very bottom by the drain plug may be a no worry issue..

But if this was my cat I would yard the diffy apart and check all the bearings.....

A slightly etched bearing will just continue to degrade and eventually tear things up....

As much as it is no fun to rip these gear boxes apart....doing it now and making sure the box is in top shape may save you a failure way out in the snow.....


As bearings fail they grind themselves to pieces and all the metal that is chewed up continues to add to the carnage....

From the pix it looks like a non drop boxed OC12
The manual is available here on the forum.....

The box is heavy but pretty much easy to work on.....

If you take it apart you can check the bands and if they need to be relined now is a great time...
Also check the drums too..

If the bands are close to being worm out...further use will eventually start tearing up the drums $$$$$$$$$$$$$$$$$$$$$$

If you venture inside....Take loads of pix.....witness mark everything so it can go back where it came from.

Keep all shim packs marked and together so they go back where they came from.

Keeping all parts in location will allow you to just replace things like bearings without any other changes...




Rig is looking good

Enjoy the project....
 

Snowtrac Nome

member formerly known as dds
GOLD Site Supporter
Thats the way it works, time is money. If you decide to bend them, if they kink you can fill them with sand, it helps with collapsing in the middle. Looks like its cleaning up nicely. If it was running when parked the tracks are likely to be your biggest challenge. Have you taken the cover off of the differential or checked the oil yet? If no water got in there you're in pretty good shape. The only other issue had with mine is it vapor locked when I got it, likely due to all the heat in the engine bay and the crappy gas they sell now days. I was able to work through it. Play your cards right and you could be on the snow this winter.
I see I'm not the only one who watched flight of the phenox when I was young and learned something useful.
 

Snowtrac Nome

member formerly known as dds
GOLD Site Supporter
Definitely check the oil in the diffy.

Drain it all and refill....

If you find water then you need to get inside that sucker and check things out.

My differential had a lot of water in it.....and there is a lot of work yet to clean that mess up.

A tiny drizzle in the very bottom by the drain plug may be a no worry issue..

But if this was my cat I would yard the diffy apart and check all the bearings.....

A slightly etched bearing will just continue to degrade and eventually tear things up....

As much as it is no fun to rip these gear boxes apart....doing it now and making sure the box is in top shape may save you a failure way out in the snow.....


As bearings fail they grind themselves to pieces and all the metal that is chewed up continues to add to the carnage....

From the pix it looks like a non drop boxed OC12
The manual is available here on the forum.....

The box is heavy but pretty much easy to work on.....

If you take it apart you can check the bands and if they need to be relined now is a great time...
Also check the drums too..

If the bands are close to being worm out...further use will eventually start tearing up the drums $$$$$$$$$$$$$$$$$$$$$$

If you venture inside....Take loads of pix.....witness mark everything so it can go back where it came from.

Keep all shim packs marked and together so they go back where they came from.

Keeping all parts in location will allow you to just replace things like bearings without any other changes...




Rig is looking good

Enjoy the project....
601's use the coveted oc- 15
 

Snowy Rivers

Well-known member
Ahhhh
Copy that
But the layout and innards are pretty much the same I would think????
Gonna have 2 pinion bearings, 2 carrier bearings
 

m1west

Well-known member
GOLD Site Supporter
Ahhhh
Copy that
But the layout and innards are pretty much the same I would think????
Gonna have 2 pinion bearings, 2 carrier bearings

OC15 is much stronger than the OC12, not that there anything is wrong with the OC12
 

Snowy Rivers

Well-known member
I could only guess by the one pic that your cat has a 12 in it.

But...no matter what it has....Rust starts in gear boxes that are sitting and have not had oil sloshing over all the parts.

The mess I found in my 12 was enough to make ya cry.

My feelings were....Another year and my 12 would have possibly been beyond easy repair.

Once rust starts on a bearing race it's only a mater of time before the bearing begins to "Shell out" and the surface starts breaking down.. Once that happens the process accelerates fast.

The failing parts shed more and more metal particles which add more hard debris to the mix and then the failure increases even faster.

I am curious about the OC15 ??? Very little mention is made about these boxes.

What rigs used them and why were they not used more ???? Was it the $$$$$$$ factor ???

Even though the 0C12 is a pretty decent box, there are areas that could be a tad stouter
 

Snowy Rivers

Well-known member
Here is a picture of one of the bearing races out of my diffy

Not a pretty sight.

This sort of crap will leave lots of junk on the magnetic drain plug too.

When a bearing reaches this point the big bang is possibly not too far away....

Sadly, many times these types of messes can be lurking and not present themselves right in your face without looking....

The gear boxes on these cats are not silent....not even....
 

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Snowtrac Nome

member formerly known as dds
GOLD Site Supporter
the oc-15 is much larger than the 12 they were used in 601 thiokols and fn 60 nodwells the most common applications
 

Snowy Rivers

Well-known member
Sounds like the OC12 was a more economical gear box across the many cats that used them.

The 2100 Packmaster is definitely no slouch....being a heavy duty machine, and the OC12 seems to hold up pretty decent....


The only contact I had with the Packmaster up until buying the one I have was running one at the ski lodge back in the mid/late 70's

I did not get involved with any of the mechanics at that time, so I really had zero to do with the machines innards.....


I would love to see the OC15 up close and personal.........


Other than the high cost of maintenance I think the Hydrostatic Cats like the 3700/4700 Thiokol/LMC machines and the much later stuff....Bully's and Prinoth....are the deal......
 

GMoose

Well-known member
GOLD Site Supporter
Here is one possible solution to your trailer issue. If you want more photos of this platform let me know.

IMG_20190125_172257406.jpg

IMG_20190125_172341658.jpg
 

PradoTDI

Member
Thanks for all the great information everyone! I haven't done much to the 601 since getting it home, mostly researching parts and planning my attack on the project. Just so I don't get anyone's hopes up, this will be a pretty slow moving project; I'm thinking it will take me a couple of years to get it up and going again since I plan to be in school finishing my degree for a significant portion of that time.

I haven't delved into the driveline at all yet, but I'm pretty confident that I can repair or replace anything it needs given parts availability. At this point I don't know if the engine even turns over; there was a compression tester in the passenger footwell which doesn't bode well. If the engine is shot my first plan was to source a Mercedes OM617 turbo diesel to swap in. There is a company that makes an adapter plate to mate one to a Ford straight 6 bell housing. I had the OM617 in a 1988 G-Wagen and loved it. However, it turns out that a friend has an old baler on his farm that is powered by a good running Ford 240. The baler needs more parts than it's worth, and my friend said I can have the engine for free. So, at this point I think I'll get that engine and if the current one puts up a fuss I'll just swap it out.
 

PradoTDI

Member
I picked up the 240 engine that my friend had in an old New Holland baler. It was the easiest engine pull I've ever done. There is a belt drive off the back of the engine, so all that had to be done was disconnect the throttle cables and electrical, and unbolt the engine carriage. Then it lifted straight off with the help of a tractor.

Due to space constraints the 601 can't overwinter at my brother's house where it has been sitting, so in preparation for moving it to winter storage I put some air in the tires. To my surprise, all the tires held 20-25psi, and the snowcat sat about 3" higher once all 8 were aired up. The trip to tow the snowcat to its winter residence was cut short by a lift pump failure on the truck, so it is currently sitting on the trailer waiting for the truck to be fixed.

I was able to get started on making a 2.125" CLR bending die for 1.25" square tube to fit my JD2 bender, the main body of the die is cut and bored for the 1" pin and the top and bottom plates are cut out of 1/4" plate.
 

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PradoTDI

Member
I've been working on designing dies that will be able to form the top and bottom bars on the grousers in a single press action. Figuring out the springback on the large-radius bends isn't easy, and is really just guesswork. Still not sure how much press force will be required, especially for the half-oval stock for the inside of the drop center, but I'm thinking about designing the dies so they can be bolted in to a hydraulic wood splitter.
 

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PradoTDI

Member
The snowcat has arrived in winter storage. I probably won't get the time to do much to the cat itself this year, so it will likely stay in this shed until next spring. I am hoping to come up with a grouser production process over Christmas break, maybe see how many parts I can manufacture during that time so I can start rebuilding the tracks.
 

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redsqwrl

Bronze Member
GOLD Site Supporter
great project. unbelievable what a couple tires taking air do for the attitude.

are your old grousers just fatigued to failure?
 
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