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Astro van cat conversion

undy

New member
Re: An introduction/hello and my project.

If you're set on using the diff and tracks from a 1200, I'd be curious how closely a 1200 chassis might align with the van, and whether you couldn't simply modify a 1200 (or other) chassis to hold that van body a lot cheaper and easier than starting from scratch?

To get the entire rear drive section, including the diff., axles and sprockets plus tracks, it may be cheaper to buy a complete "parts" cat that includes all of those parts in decent shape rather than to buy them separately.

I'm thinking blown engine, abandoned project cat, etc. Install your drive train. Fab up some sliding body mounts, and finish the details.

Unless it's just to enjoy the creative engineering process (hey, each to their own), there might be no big benefit to reinventing the snowcat wheel. Plus it's always more expensive to buy a vehicle part by part and assemble it. Now, if you just like to build stuff, I say go for it!
 

Snowtrac Nome

member formerly known as dds
GOLD Site Supporter
Re: An introduction/hello and my project.

I can get you a m29 weasel differential to for your van project might work good weasels would do up to 30 mph which would allow your van cat to run circles around the krusty crowd who think they have the fastest cats on the snow.
 

Snowy Rivers

Well-known member
Re: An introduction/hello and my project.

I see the unit for sale or ??? on page 10


I have looked at several used cats (Thiokols) and every one had the usual cracked and broken frames, brackets and other damage.

Considering that most of the machine is going to wind up on the scrap pile after I get done stripping it down to the frame, I am still pretty dialed in on building a new frame that will be designed to work with the Safari body, V6 engine and 4L60 trans.

From my perspective new "Zero hour" materials cut, welded and built to fit will be far better than used heavily flexed and stressed materials.

The 1200 series frame is so simple, plus adapting the V6 will require the engine mounts be altered anyway.

My little shop has a 9x42 Bridgeport mill, Takasawa 16 inch lathe, Millermatic 250 wire feed welder. A plasma cutter, Jet band saw and the usual 3 rollaways full of hand tools.

AND A BIG HAMMER:biggrin:

Building the new frame will take a minimum amount of work and really not all that much $$$$

I can buy just what I need and toss very little.

I scared up the 5.30 x 12 tires and wheels from a distressed freight yard.

Lovely white spoke'd 5 hole wheels.
Looked to have been in a flood maybe... Very dirty and muddy, but on a pallet with shrink wrap still around them.

$100 for the pallet load.
Good application of hot sudsy water will make em look new.

Ended up with 12

The tires are not 10 ply, but for now we can use these and later replace the two fronts with the heavier tires and foam them.

The Flexiride axle units are on my list and will likely turn up in my pile cheap.

When patience is coupled with a knack for scrounging, anything is possible.
 

Snowy Rivers

Well-known member
Re: An introduction/hello and my project.

The Weasel axle can certainly be adapted to work.

The OC12 sprockets can be made to work with adapters if need be.

Hmmmmm.

Interesting.
 
Re: An introduction/hello and my project.

trailer tires will not work----been there done that----did you check with the minn.out doors scrap and see about maybe some axles and tires----I also have some packmaster 2100 recovered sprockets with your mill and some math you can re drill them to fit any rear end----or build adapters
 
Re: An introduction/hello and my project.

track guiles will go through side walls---when your tracks r on uneven ground----your track/ cleats/grosers don't always stay flat on the ground----the only ones that did were the old tuckers with pontoons
 

Snowy Rivers

Well-known member
Re: An introduction/hello and my project.

Gotcha.

I scored the stack of trailer tires/wheels, so will use them as a setup to get the machine up and running and then deal with better rubber as time rolls on.

The low cost for the stuff I got will not cause great worry at this time.

Looooong way to launch date at present.
 

Snowy Rivers

Well-known member
Re: An introduction/hello and my project.

The Tucker had an all together different set up.

Used to drive one of them suckers loooooong ago.

Snowmobile club had one that we groomed with.
I liked the Thiokol Spryte far better to drive.
 

Snowy Rivers

Well-known member
Re: An introduction/hello and my project.

Sitting here watching the snow come down and going over the Safari electrical manual.

Came to the conclusion that retaining the steering column to keep the ignition key switch, the multi function switch (Dimmer, wiper and turn signals) and the shifter for the auto tranny.
The dash is the digital unit, so keeping things intact will facilitate an easy conversion.

Spoke with a fella this morning about re calibrating the Drac module (Drives the speedo) to reflect as close as possible the real time vehicle speed.

He told me he needed the tire size :ermm: ????
I sent him a piccy of the Astro cat and got him on the same page.

He says if we can pace the rig and note the actual speed vs what the speedo reads that he can mod the drac to get real close to actual speed.

Going to retain the factory fuel tank/ sender etc, but mod the pickup tube to allow a low pressure external electric pump that will work with the Carter carburetor.


Looking at some purpose designed brake line quick disconnects to allow the body to be rolled back for service as well as quick connects for the fuel, heater lines etc.

The ideas just keep flowing and I'm getting them jotted down on a build sheet to refer to later as time goes by.

Looking for a pair of original steering cylinders and levers, but may end up building the set up from scratch.

Will just remove the steering wheel and add a flange adapter to keep all the stuff in the column where it belongs.

Obviously the turn signals will not turn off after a turn :yum:

Will be nice to be able to leave almost all the wiring and stuff from the body intact.

Decided that during the overhaul of the 4L60 that I will mod the box to delete the lockup converter.

This feature was designed for light cruise loads anyway and there is no light cruise in a cat... it's all uphill...

A heavier converter can be built that will offer better power/torque with less heat.

Not sure if the overdrive 4th gear will be of any real advantage, butttttttttttt ????

Gonna set up a disc type drive line brake to work off the stock brake pedal in the Safari.
That will make the driveability more user friendly than needing to haul back on both steering levers to make a normal stop.

Looking like we will need to get a custom shifter cable made to work with the set up due to the relocation of the engine and tranny.

Was thinking about the other engine systems and the power steering pump will not be needed, so an idler for the serp belt will be a must have.

Again thinking about engine stuff and gave though to the AC system, hmmmm AC IN A SNOW CAT :yum:

May keep it for summer excursions in the dirt. :brows:

And the snow is falling
 
Re: An introduction/hello and my project.

just so you know you can use in tank fuel pump---go to jegs or summit and buy adj. fuel pressure reg. with return---works great----and it also always supplies cool fuel to carb---I did it on my 3500 hd after taking off junk tbi------your tranny and converter will be fine leaving it stock---leave lock up converter in and put a switch on it---and on my 3500 hd dually it has the 5 speed auto in it including lock up so I added a switch for 4th gear lock up and built a six speed tranny----I would leave the transfer case in it so that you will have low range if the all wheel drives had it-----and for your speedo that really is not imp.---you can adj. it with a good scan tool----or stick your gps to the dash----here is thunder that I did my tbi to carb and six speed tranny-----so I know it works
 

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Snowtrac Nome

member formerly known as dds
GOLD Site Supporter
Re: An introduction/hello and my project.

may not be able to do that with they astro some had all wheel drive with a viscous coupler others had the electronic clutching t-case the electronic case would likely work but the viscous would not work with out the front shaft being hooked up
 

Snowy Rivers

Well-known member
Re: An introduction/hello and my project.

I have used the regulators on rigs in the past.
This sucker is gonna have the tank is a real nasty spot to get it out (get pump out if it fails) that I want a regular external fuel pump mounted where it can be accessed real easy.

Not too much worries about the fuel getting overheated in a snow machine.

The 700R4/4L60 converters are very small inside and removing the lockup clutch makes room for a bigger turbine and pump and stator assembly.

With top notch welded blades it will give a lot more output than stock with far less heat being churned out.

The lockup in this application is pretty much worthless.

I am not even real sure how much good the overdrive will do.
Possibly on level hard/packed snow it will give a better top speed, but I will be extremely happy if the beast can muster 30 mph and keep the tracks on.

The transfer case on the Astro/Safari vans is an all wheel drive single speed unit and must have the front shaft connected or the viscous coupler will fail real quick.

I promised the T case, front axle and rear axle to my kid for his GMC 5 window project.

With the gearing these cat rear drives have and the 3.06:1 1st gear in the 4L60 there shouldn't be an issue with low gears for crawling around.

The 4l60 has 3.06, 1.63, 1.00 and .70 for ratios

This spread should be sweet.

A good "Dash 2" shift kit will make the gear changes quite firm and keep the gear box alive even under some tough romping.

I am not even a fan of the 700R4/4L60 tranny, and have ripped up several in my time.

Butttttttttttt.
With a handful of good after market parts they can live.

The older Sprytes had the little C4 Ford auto in them and they are a very tiny box.

I just want to think through the possible failure points and fix them before they break ya know.
Also want to keep service items in places that can be repaired easily out in the bush and not require a warm shop and a ton of tools.

One item in point is the fuel pump.

Locate it so it can be easily accessed from the dog house or ??? without needing to crawl under the cat.
Even if we need to chop an access port in the floor and put a little cover on it.

I have been stuck out in the bush several time with stuff that was a nightmare to fix.

Always carry a spare HEI cap with coil, rotor and a module.
Spare fuel pump and filter.

A little small carter 4 bbl carb is nearly bomb proof, so little worries.

A spare serp drive belt never hurts and a gallon of green juice.

There is always something that can grab ya by the butt, but ya can't carry a new rig with ya.

Other items that will get replaced will be the starter and the ignition switch.
At 25 years old and 125k on the clock the starter has seen many duty cycles as has the ignition switch, both of which are not handy to swap out under nasty weather conditions.

All in good time.

The engine is basically low miles with only 125k so not too much worries.
Will steam clean the engine and replace the soft plugs, add a block heater.

The top valve covers will get new gaskets or silicone, whichever they take.
Maybe a rear main seal if need be while the tranny is on the bench getting a complete rebuild.

Been a few years since I pawed through a 700R/4l60 but I have the special tools needed to install the clutch seals and the drivers to R&R the bushings.

Will see if the planets are good and reuse, but doubtful I will upgrade unless they show issues.

The V6 is not that tough on trannies, so will just play it as it comes along.

My goal is dependability, and easy access to fix little issues that are usually stuff that's buried in a real beotch of a place to get at.

This thing will be mostly a toy, but when I need it, I expect it to work 110% without issue.

I have helped fix broken stuff in the snow before, and I don't like it.
 

Snowy Rivers

Well-known member
Re: An introduction/hello and my project.

may not be able to do that with they astro some had all wheel drive with a viscous coupler others had the electronic clutching t-case the electronic case would likely work but the viscous would not work with out the front shaft being hooked up



Yesssss.
Plus that case just adds weight I don't need or want.

While the 4L60 is on the bench I will stuff in a 2wd tail shaft and tail housing.

I have to tear it clear down anyway, so no biggy to swap the shafts.
 

Snowy Rivers

Well-known member
Re: An introduction/hello and my project.

Question time. ?????

What is the bore diameter of the master steering cylinders used with the C4 and OC12 DIFFIES

I need to start designing the steering level/master cylinder brackets, levers and such to fit in the cockpit of the Franken cat.

Getting a standard master cylinder of a single piston design should be a snap and using a standard off the shelf part will make it even better.

The controls need to be offset to the left enough to allow easy access to the existing brake pedal by the operator.

Looks at present like the right side lever will need a distinct curvature to facilitate comfort for the operators right leg while using the service brake pedal.

Piston or bore size would be sweet.

Thanks.
 
Re: An introduction/hello and my project.

just so you know-----if you need to stop you pull both turning brakes back at the same time----so scrap the break pedal------------and iam sure you have already noticed but if you go to cats for sale section----ad that says three cats for sale----there is rolled up tracks in the back round
 

Snowy Rivers

Well-known member
Re: An introduction/hello and my project.

Yessss
Fully understand the operation of the Thiokol
Ran one for several seasons

I want the auxiliary brake in the original place to avert a novice driver (Spouse) from panicking and crashing.

An easy addition to add a drive line disc brake and operate it off the original brake pedal.

The auto tranny has the parking lock and that will be fine for most situations except maybe a really steep grade.

May go with a drum type brake and use the cable... ???? Not sure as yet

I want this machine to be as intuitive as possible to drive.
The gear selector, ignition key switch, brake pedal, wiper control, service lighting, turn signals etc will all be in the original locations and function as normal.

Also the brake pedal has its factory light switch that works fine installed.

All this stuff cost $$$$$ to replace and redesign/relocate and it all functions well.

The only real difference from driving the Van will be the use of the steering joy sticks instead of the steering wheel.

Simple and cost effective plan me thinks.

If it works don't fix it:smile:

Also all repair parts for anything that is connected with the Safari is available at any NAPA, Auto zone or ???? parts house.

The plan is to use as much standard off the shelf parts as possible when and where they are added, changed or otherwise
 

Snowy Rivers

Well-known member
Re: An introduction/hello and my project.

just so you know you can use in tank fuel pump---go to jegs or summit and buy adj. fuel pressure reg. with return---works great----and it also always supplies cool fuel to carb---I did it on my 3500 hd after taking off junk tbi------your tranny and converter will be fine leaving it stock---leave lock up converter in and put a switch on it---and on my 3500 hd dually it has the 5 speed auto in it including lock up so I added a switch for 4th gear lock up and built a six speed tranny----I would leave the transfer case in it so that you will have low range if the all wheel drives had it-----and for your speedo that really is not imp.---you can adj. it with a good scan tool----or stick your gps to the dash----here is thunder that I did my tbi to carb and six speed tranny-----so I know it works

Welder

I am curious, what trans do you have in the 3500 truck ???
 

Snowy Rivers

Well-known member
Re: An introduction/hello and my project.

Yesterday evening the snow started falling and by this morning we have picked up nearly a foot overnight.

We are 25 miles south of Portland and this morning the PDX METRO area is a mess.

Anyway...
Yesterday I scared up a pair of the Ford E100 brake master cylinders that seem to have been quite popular on the Thiokol cats.

These have the pivot on the end.

As soon as they arrive I can start working out the details on the lever pivots and machine a set as well as fabricate the floor bracket and the levers themselves.

Decided to make the levers themselves separate from the pivot clevis so the levers can be removed to allow any under dash service to be done without a serious fight.

Getting the steering wheel out of the way and the tilt column fully up and out of the way will allow a "sit in" and some seat of the pants "touchy feely" design work to build the levers so they are comfortable to use.

Gonna get some of these little snively items done and ready to go.

Even though its a long way until we will need them.

As time and materials become available things can move in many directions.
 
Re: An introduction/hello and my project.

4l80e-----------and remember the shift sol. work on ground-----so pulling a load I can go 1/2/3 lockup----than 1/2/3/4 lockup---the 1/2/3 lock up gives me that in between gear works great----and with the switches I can go down r blvd. in lock up with just an idle none of the up shift down shift crap------and no---- it doesn't stall at lights if you leave switches on
 
Re: An introduction/hello and my project.

the other thing u need to check out is how your tranny shifts----if you take tbi off and use a different dist. it might not shift----none of my trucks use at small of a tranny----I think if you have a kick down cable it will shift----if not it will run in limp mode----some computers will not let it shift at all----my 3500 hd would shift to 3rd----no 4 th or lock up---------no will never get past 3rd in your cat-----trust me
 

Snowy Rivers

Well-known member
Re: An introduction/hello and my project.

My tranny is the non electronic 4l60 with just the Throttle pressure cable
Its the 700r4 with a different name.

Been into bunches of these boxes.

All governor shifted.
 

Snowy Rivers

Well-known member
Re: An introduction/hello and my project.

You can install a manual shift control setup on the electronic units to allow control 1 2 3 4 by the selector

I will fool with the governor springs to get the shifts where I want them.

Will start off with the stock ones and see what it does.

With the low gears in the OC 12 box it may hike right up.

I am thinking that the thing will be manually selected a lot to keep the tranny from being extremely busy.


Today I scored a pile of goodies.

Edelbrock intake for the V6 as well as an Edelbrock 4bbl carb and a billet HEI distributor.

Very right price too

Local fella called me on my Craigs list ad.

Working on the design for the steering cyl/lever bracket
Gonna need to mock it up to get it comfy.

Lotsa cardboard cutouts and measuring.

Measure lots, cut and machine stuff once. :biggrin::biggrin:

I am a stickler for mocking stuff up and seeing how it looks and in this case if its ergonomic for the operator.

Having your tranny so you can control the shifts is nice.

If you run the 4L80E in 3rd and load the converter clutch it needs to have the multiplate conv clutch to really live a long time.

Most converter clutches are designed for light cruise use at low torque for top mileage.

I love the look of your Thunder :biggrin:
 

Snowy Rivers

Well-known member
Re: An introduction/hello and my project.

Yesterday afternoon I physically got my hands on an Edelbrock intake, a standard carb intake, 2 Edelbrock 1406 carbs and 2 HEI distributors.

Been dealing with the fella on the text mssg for a few days, and yesterday we got together.

Looks good for $300
Will likely high grade the stuff and sell what I don't want.

Seems that factory cast iron 4bbl manifolds for the v6 are a desired item.

Will see where we go.

Gotta check it all out.
 
Re: An introduction/hello and my project.

ROLLING THUNDER is bad asssssss---wheel adapters with 22.5---with 40 inch tires----6 inch lift-----gm crate motor---electric header cut outs ---molded in trans am shaker hood scoop ---old school gauges out on hood--bush wacker cut out wheel flares------all imron paint----stainless bumper----thunder is getting a big brother-------iam building a 7500 topkick----------there is a story why we call it rolling thunder
 

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Snowtrac Nome

member formerly known as dds
GOLD Site Supporter
Re: An introduction/hello and my project.

does the topkick get a gas guzzling big block too or are you going to put a real motor in it like a c series cummins or a 3306 cat
 
Re: An introduction/hello and my project.

cannon------keeps my neighbors on there toes---lol----restoration job for vfw-- cannon got 3 tone winter paint ---looks cool but was a lot of work(taping)---topkick is a 427 gas on propane---topkick is just another toy---gas mileage not important ---but I do have to look good going through town
 

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