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Thiokol 4t10 engine

mradecky

New member
1961 Thiokol 4t10 trackmaster

I am restoring a 1961 Thiokol 4t10 and am interested in any information I can find including an operators manual, info on the drive mechanism and parts. I need the most help understanding the drive unit.
Thanks,
Marc
 

Melensdad

Jerk in a Hawaiian Shirt & SNOWCAT Moderator
Staff member
GOLD Site Supporter
Re: 1961 Thiokol 4t10 trackmaster

Good moring Marc, is the trackmaster you are referring to one of the University of Utah variants that seated roughly 10 people? I've seen a couple different track types on those, so can you describe, or better yet post some photos of the tracks, the unit, etc?
 

mradecky

New member
Re: 1961 Thiokol 4t10 trackmaster

It is a 10 passenger cat with a ford 390 inline 6 cylinder with a 3 speed transmission. I will try to post some pics later today. The area that I am in need of the most help is with the steering mechanism.
Marc
 

Melensdad

Jerk in a Hawaiian Shirt & SNOWCAT Moderator
Staff member
GOLD Site Supporter
Re: 1961 Thiokol 4t10 trackmaster

You probably have an OC 4 or similar transmission that controls the power to the tracks, we have a couple members here who are familiar with those. I know what they are, but not really how they work. I'm sure one of them will chip in some help. The snowcat forums are a little slow this time of year so you may have to repost to this thread in a week or so to bring it back up as a current topic if you don't get any responses.
 

mtntopper

Back On Track
SUPER Site Supporter
Re: 1961 Thiokol 4t10 trackmaster

mradeckyIt is a 10 passenger cat with a ford 390 inline 6 cylinder with a 3 speed transmission. I will try to post some pics later today. The area that I am in need of the most help is with the steering mechanism.
Marc

Marc,
The engine is probably a 200, 223, 240 or 300 cubic inch 6 cylinder Ford as the 390 was a V8. The engine is most likely a 200 if it is the original engine.

This previously posted info below may apply to your machine: I do not know as much as these two members about the Trackmaster 601. You may want to contact them about how the steering operates. These 601 machines are very unique and parts may be hard to get today. Keep us informed of your progress.

Bill

mkntraks http://www.forumsforums.com/3_9/showthread.php?t=4477&highlight=Sale--1961+Thiokol+Trackmaster
Re: For Sale--1961 Thiokol Trackmaster this machine does not use a steering differantial like the oc 4 it has a clutch system tht supplys power to two right angle drives some had dana 60s and earlyer ones used a dana 30 series but is no longer avaible

mtncrawler http://www.forumsforums.com/3_9/showthread.php?t=3284
Thiokol 601 I am not an expert on the machines by any means. I am posting what I think to be true however I hope anyone will correct me where I am mistaken so I can learn more about these machines. Sometime in the early '50s the University of Utah built several prototypes of low ground pressure machines for Morton Thiokol for use in missile testing programs taking place on the salt flats. The most sucessful of these was the 4VL. It had a drive system where the the engine power went into a gear box where it was split into two output shafts each running through its own clutch and brake. Then two separate driveshafts took the power to two truck style differentials welded together with the outboard axles turning sprockets to drive the tracks. Pulling back on the steering lever first disengaged the clutch, then applied the brake when pulled further, turning the machine. This drive system was most likely very difficult to keep properly adjusted and at any rate not very strong. The last body style used had the reverse sloped windshield and would become the 601 series. The 601 drivetrain went with a Ford inline six cylinder engine, 4-speed standard transmission, and a OC-15 steering differential. The military spec machines used the Ford 240 cu.in. and the civilian version could be ordered with the Ford 300 cu.in. engines. Oliver Tractor Corp. made crawlers using Clark steering differentials, notably the OC-4 and OC-12 which were used in the Thiokol Spryte, or 1200 series, machines. The OC-4 was also used in the Thiokol Imp. They did not build an OC-15 crawler so I believe this differential was made for military contract. The military 601 was mostly used for airfield recovery. I am somewhat puzzled by the example I own since it has the 300 engine, no roof hatch over the passenger seat, yet was originally painted blue (Air Force). I have heard these vehicles refered to as "Trackmasters" and have a maintenance book cover that says that too. They are very heavy duty especially by snowcat standards.
__________________
 

mradecky

New member
You are correct the engine is a 290/300. I will attach some pics.
Marc
 

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byoung

New member
Hello Marc,
Bill asked me to have a look at this thread as I have two Thiokol units myself. However both utilize the later Clark OC-12 rear end. I have looked under one of those things and wondered probably many of the things you are wondering now. Sorry I can't be of more help.
Brad
 

mkntrakes

Active member
well here's my two cents the motor in that machine from factory had a 223 ford parts are real hard to find. the transmission turns a clutch system as far a i new the trans was a 4spd.the splitter has four clutches two for low gear two for high with a neutral the way this operates is you put the trans in a gear then push levers forward then you can stop one track by putting in neutral pos this takes power away from the track or pull lever to rear for low gear which keeps power to track but at a slower speed which makes it turn to the slower side. there was two models of this unit one was a 4vl series and a 4t series the difference was in differentials size also i think the 4vl had wood cleats and the 4t had a steel cleat
 

mradecky

New member
mkntrakes,
Your description is very accurate. Do you know who manufactured the clutch system or if anyone has parts for this system. My machine is a 4T and has the steel cleats.
Marc
 

mkntrakes

Active member
i bought some disks from a john deere dealer the splins were the same but the out side diamerter was smaller all i bought was the fiber disks then i sanded steel disks to remove rust not sure if it will work built ths unit about two years ago for my 4vl then got on to other project and haven,t had time to get it put it back in the machine hold on to your wallet as i remember there were about 1200.00
 

mtncrawler

Bronze Member
GOLD Site Supporter
Unless you can rebuild or fabricate the pieces you need it may be worth looking into a drivetrain change. Sorta depends on how bad you want that body style and what you want to do with it.
 

Catless

New member
Marc:

You may want to contact Art Seely at Safety One for info on the clutch discs that you need.

I looked into buying one of these units about 4 years ago in Grand County, Colorado. I called Art and he more or less talked me out of it........It seems that the discs are difficult and expensive to procure........Art indicated that they can be found from "antique tractor dealers" for a price.......problem seems to be that these units need a "bunch" of the discs........

As my name implies, I am indeed CATLESS so I am no expert.

Art Seely
WWW.Safetyoneinc.com
(303) 734-0772
(800) 485-7669

Good luck with your restoration!
grd
 
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