ST-4 Recipes

Picked up an ST-4 last year and I'm finally getting around to working on it. It is mostly complete except the cooling funnel and non working guages.

Right now it has a 1600 dual port engine in it and needs a lot of wear items replaced (drive sprockets, one of the drive chains and inner sprockets, brakes, etc.)

Knowing what you do now, what advice would those of you who have resurrected these machines already pass on to save time and frustration, if you could go back in time and talk to yourself when you started?

What engine would you recommend, since mine is pretty tired. (1600, long stroke torque motor, higher revving 1600 etc.

Which clutch would you run?

If you rebuilt the variators, what parts should you have ordered before you tore them apart?

For brakes, would you have rebuilt the stock ones, or adapted disc brakes on to begin with?

For tires, are aircraft tubes thicker than the cheapo junk I can find on ebay?

Would you change anything in the suspension to make it ride smoother? Would you have added anything to deflect the snow build up on the tracks and bogey wheels?

Would you have insulated the cab or floor?

Do you prefer alternators, or generators? I plan to run LED lighting, so the amp draw will be less.

I'm moving the fuel tanks out to the fenders. Do you like the boat tanks, or should I pay up for some aftermarket pre-fab tanks like race cars use?

Where are you located?

I have not thouraghly rebuilt mine yet but have used it for 4 winters now.
I would not insulate the floor. Just no need as they warm up just fine inside without any insulation.
I would use a stock 1600 sp, a good rebuild should last a long time in one of these.
I find you don't need the brakes much but they should work. I would just rebuild your current system. I have disc brakes on mine and really don't see the need. Good working drum brakes should work fine.
To soften the ride, stay on powder.
Seriously though I don't think you are going to change the ride much unless you go all air in the tires. Mine are all foamed and I would recommend foaming yours. The ride is not rough, maybe a little noisy but not rough.
I would use the stock clutch.
Mine has an alternator but I wouldn't mind a generator either. I think either will do the job just fine. I run all generators in my vw busses and put tons of miles on those with no issues.
Mine also has the boat tank mounted on the right front fender. I have not had any problems with mine. I like that it is outside and easily removable for filling or replacement or just getting it out of the way while you're working on it. I also like to keep the fenders along side the cab open for boards and skis.
I can't add much about the variators because I haven't messed with mine much.
Good luck with it and post up some pictures!

willd said:

Picked up an ST-4 last year and I'm finally getting around to working on it. It is mostly complete except the cooling funnel and non working guages.

Right now it has a 1600 dual port engine in it and needs a lot of wear items replaced (drive sprockets, one of the drive chains and inner sprockets, brakes, etc.)

Knowing what you do now, what advice would those of you who have resurrected these machines already pass on to save time and frustration, if you could go back in time and talk to yourself when you started?

What engine would you recommend, since mine is pretty tired. (1600, long stroke torque motor, higher revving 1600 etc.

Which clutch would you run?

If you rebuilt the variators, what parts should you have ordered before you tore them apart?

For brakes, would you have rebuilt the stock ones, or adapted disc brakes on to begin with?

For tires, are aircraft tubes thicker than the cheapo junk I can find on ebay?

Would you change anything in the suspension to make it ride smoother? Would you have added anything to deflect the snow build up on the tracks and bogey wheels?

Would you have insulated the cab or floor?

Do you prefer alternators, or generators? I plan to run LED lighting, so the amp draw will be less.

I'm moving the fuel tanks out to the fenders. Do you like the boat tanks, or should I pay up for some aftermarket pre-fab tanks like race cars use?

Click to expand...

I hate typing this early in the morning give me a call we can talk about it I have made mods for my area and I know the aircooled engines like the back of my hand see what I mean for got my number 907 434 0692

That is all good advice. I would also check the condition of the driveshaft to brake drum splines and the brake cylinders as they are prone to rust. If you need new chains and are having trouble sourcing the drive chain you could have the teeth on the large and small drive sprockets reprofiled to work with ANSI chain rather than the harder to find metric. Track snow deflectors of either design would be a good idea too.

Sorry I haven't gotten back to any of your PM's. This week has been pretty busy.

I'm right outside of Reno so I will be using this thing up in the Sierra's or wherever we decide to drag it.

It has seen a lot of use over the years so I'm sure there is a lot of work to be done. Mileage is unknown, speedo appears to have been broken for a long time.

Don, I keep trying to get time to call you but I have 3 kids and a full time job so fitting in private time for dad to make a phone call is pretty sparse.

This is my first go around with VW anything but I do all my own stuff on my vehicles and I grew up on a Farm / Ranch so I'm fairly familiar with mechanical things and equipment.

I have a lot to learn about owning a cat but I'm on a mission to make it work even if I have to spend all my free time on here and reading manuals.

My primary concern is reliability since I will probably be doing everything on my own unless I make friends with someone close that has a cat.

Not too concerned with speed but if it costs the same to do a 2200 cc motor as to rebuild my 1600 then it will probably get a displacement increase.

As for insulation, I did not insulate but I did overspray both the underside and the inside with a 2-part epoxy that is similar to Rhinoliner. It was a rubberized slightly expanding epoxy and it helped dull/soften some of the noise. This is not simple paint or a roll on product. It was a thick (about 1/8") spray. I had to mix the epoxy and add shredded rubber then sprayed it on the whole underside and the lower part of the inside of the cabin.

Not sure if it provided much insulation from cold, but it did provide a little insulation from noise. If I had to do it over again I'd probably spray the entire inside of the cabin AND also spray the outside under the running boards and the lower area of the outside of the cabin next to the tracks instead of just the bottom of the cabin.

It can be tinted. So it starts out a very light grey, but if you want to match it to the orange it can be tinted to match.

As for engines, I have been looking for options on mine. Single carb is the rule of the day. Not enough room for dual carbs.. This limits what you can run for a camshaft, as well as the total displacement of the engine.

From what I have learned, 1770 cc's is about the biggest you can run with a single carb, and that is with a stock camshaft.. Other wise the carb will not handle enough air to feed the larger displacement..

One thing I will do for sure is replace the crankshaft with a fully counterweighted crankshaft. VW engines don't have counterweights on a stock crank. With counter weights, they run smoother at all speeds, and last longer, as the engine case isn't being hammered by vibrations..

There are bushings in the pivot points in the suspension. These are made of phenolic, a resin and linen based material. When they wear, your bogie wheels don't track straight, and your tracks usually run to the outside, wheels against the steel track guides. This causes vibration and noise in the cabin. I made bronze replacement bushings for mine, and there is less noise and vibration now.. The machine also coasts to a stop when you engage the clutch. Before is just stopped..

Ask questions here as you go about getting you machine ready. Lots of owners who have walked the path, as you are about to....

Regards, Kirk

the one improvement I could suggest is the strut that supports the center spring is prone to fatigue get 7 feet 0f 2inch od 1/4 walled tube remove all through bolts and drive it all they way through and re drill holes you will never break there again.

Thanks all.

If you use fender mounted tanks make sure that you have a shut-down valve to prevent fuel from auto-siphoning when engine is turned off. This will end up filling your oil with fuel if not careful.

SNOWTRACK with GM Ecotec 2.4 engine

Engine is a perfect choice for Snowtrack!

No modifications to the engine: exhaust manifold on the correct side

Cabine water heater is so much fun, cabine a lot less noisy, 175 HP

[ame="http://www.youtube.com/watch?v=5nuNucXn32g"]http://www.youtube.com/watch?v=5nuNucXn32g[/ame]

what did you have to charge or modify to install a different engine? im looking to put a Toyota 22re or a Nissan se6 in.