All Small Six Snowcat with a Six - Getting a 1968 Thiokol Spryte up to Speed!

[aussie7mains]

Your alternator might already be a high output, the 2 sheave drive pulley would suggest that. Just a thought here, LPG is good at low temps, and is pretty well impervious to angles, so that might be an option for you? Only drawback might be refilling? The 200ci might be an industrial engine, I see its an auto trans, C4? I would just make sure everything is working correctly, then enjoy it. What does it do for track drive, ive never seen anything like this in Australia, we dont have enough cold weather or snow for this sort of rig.

 

[CHCzecora]

@TrickSix:

• I’m all in on the simple “bolt on” theme, exactly what I need (and my wife thanks you keeping me in check budget-wise!).
• I’ll likely have to remove the radiator to get to the front of things, so I’ll get the flush done then. Very likely I’ve got to stick with the current size with the frame/existing build out.
• I’m eager to get that fan on… it should have an existing place to bolt on, right?
• It does have manual choke, but I only have to use it sparingly.
• While I’m the front with the alternator and fan business, I’ll put in a water/coolant heater. Summer starts are easy and I’m more convinced this will be a game changer in the Winter
• For next year’s and future mods, I really don’t think I’ll get that engine out for machining… it is just so deep in there! Maybe I’ll learn more as I head into the front through the radiator. Ignorant question: can I take off the head while the block remains in the doghouse?
  • Tabling, but saving your advice about the two barrel carb. Thanks.
• As for other engines… I really need to not go down that rabbit hole or I’ll get lost forever.

Looks like @Frank has another 1-wire alternator advocate in @hodaka100 … interesting. I’ll likely get bolder with the electrical work as I move forward. Thank for the advise.

@pmuller9 - good eyes on the rubber vacuum caps, I’ll dig in there.

 

[TrickSix]

The fan mounts on the front of the water pump pully, usually with a spacer of variable lengths depending on the application. I'll measure my fan diameter tomorrow (unless someone knows it right now) and you can cut out a cardboard circle the same size. Hold it up in front of the engine centered on the water pump pulley an inch or two out to see if you've got the room to mount it before you go to any more trouble. Bear in mind the fan will be thicker than a piece of cardboard.

P.S. - If you notice any signs of the water pump seal leaking while you're getting a good look at the front of the engine, and decide to replace it, while it's out is an excellent time to flush out the block too.

 

[CHCzecora]

@aussie7mains:

• I think I’ll run with the heater first, but I’ll look into LPG, but it does seem like a pain to source.
• Yes, it is mated with a C4 transmission.
  • That actually brings up the fact that the rebuilt starter I just put in isn’t great. In fact, I bought two just in case and I was justified - the first one just didn’t mesh well/at all, and now the second one is having a hard time retracting and chatters too much for my comfort (any chatter is likely bad anyway, right?).
  • Also, there is no bell housing cover and that seems weird.
  • The teeth on the flywheel have suffered from all the starter abuse. Is that a whole rebuild or (hopefully) easier replacement/upgrade?

One more overall thing… noise is an issue. It is deafening sitting right next to this six. This might be sacrilege, but amidst all this, is there any engine work to make it quieter?! I’m looking into better insulation/sealing on the dog house, but until then everyone is in cheap Harbor Frieght earmuffs and I’m thinking of putting a headphones comms unit like a small aircraft.

 

[TrickSix]

And take pictures while you have the radiator and other stuff out.

 

[CHCzecora]

@aussie7mains - It is a differential brake-based steering system via two hand levers. Pull back left, you go left. Pull back right, you go right. Apparently it has “bands” that wrap the diff for the braking. Other snowcats have fancy hydrostatic joysticks but this one is like doing an intense cable row exercise every trip. Pretty fun, but I’m skeptical of my wife or my younger teenagers being strong enough to safely drive it.

 

[aussie7mains]

@aussie7mains - It is a differential brake-based steering system via two hand levers. Pull back left, you go left. Pull back right, you go right. Apparently it has “bands” that wrap the diff for the braking. Other snowcats have fancy hydrostatic joysticks but this one is like doing an intense cable row exercise every trip. Pretty fun, but I’m skeptical of my wife or my younger teenagers being strong enough to safely drive it.

Yeh, I found some info on it, external band brakes with a heavy duty differential. Basic steering which is OK for low speeds, bit like a bulldozer, without the clutches. Is there a steel plate between the bellhousing and the block? This actually locates the starter, without it you wont get correct mesh. As to noise, not a lot you can do there except isolate the noise with acoustic material.

 

[TrickSix]

I measured my 6-bladed 6-cyl AC fan diameter. It's about 15", maybe 15.25". The blades are mounted in an asymetric pattern. There are a lot of different V8 fans out there, I'm not sure if any of them would fit. A quick look on ebay found a few of the 6-bladed fans, but they wanted a lot of money. Sometimes you see them cheap because the seller doen't know what they are. A possible alternative would be the Bronco 170 fan, it looks very similar - six blades in an asymetric pattern, and reasonably priced.

Another PS - Yes, you can remove just the head without pulling the whole engine. It looks like you've got enough room, but the head is heavy and you'll want some help lifting it out.

 

[B RON CO]

Hi, a common cause of an engine running hot is improper ignition timing. Our engines seem to run better with @ 10* to 12* initial timing. Also make sure the vacuum and mechanical advance is working. Good luck

 

[63 Sprint]

Lived near Crested Butte, Colorado in the 1980’s while running a job, and I can tell you that propane goes back to liquid when temperatures go down to -44 degrees F. All forklifts that were used outdoors were gasoline powered. “Not Propane“.

We’ve seen temperatures below -40 F. regularly at the lower elevations 8,000 to 9,000 feet. At the time, most vehicles were plugged in to aid in starting.

Edited: Removed unnecessary content.

Honestly, from what I’ve been through in different places in the country in extremely cold weather. Stay with gasoline, and have a few cans of ether with you just in case.

When people’s lives depend on engines starting up to get them to safety, they better have a vehicle that is able to start with starting aid in extreme weather conditions. And, propane is NOT a fuel to use in such conditions.

 

[63 Sprint]

Hi, a common cause of an engine running hot is improper ignition timing. Our engines seem to run better with @ 10* to 12* initial timing. Also make sure the vacuum and mechanical advance is working. Good luck

Another common cause of engine overheating in very cold conditions is radiator coolant freezing in the radiators. It happens more than some think. It also happens when the vehicle is moving down the road. How do I know. It happened to a friend. A belt driven fan can draw to much super cold air that the radiator core freezes up. Oh, in extreme cold conditions, using a higher temperature range thermostat helps.

When I used to build generators that were used in cold climates, quite a few were spec’d to use electric fans.

 

[sixtseventwo4d]

From what I am seeing in your pics is a pre-existing electric fan someone put there most likely thinking it would combat an overheating issue.
If you go back with an engine-driven fan you will need to fab up a fan shroud to get optimum cooling. Something automotive might can be made to work well enough if you take measurements before pulling the radiator.
Maybe you can backtrack the Cats life and find the original fan and shroud?

 

[Frank]

“TUFF STUFF”! - Ha! Looks like solid, American-made goodness. I need to ID and test my current one, but my guess is that I’ll keep the existing wiring to not disrupt things too much if/when I upgrade

No matter what your current alternator amps output is, it will not charge like this one at low rpm. This alternator uses a single 10ga wire directly to the battery, that's it. your current regulator wiring can be left, or removed intact in the event of later use. surprising how much clutter the wiring and regulator box make, engine bay is much tidier without it.
Posted as FYI, as you consider options.

 

[Frank]

A two barrel carb upgrade is not going to be very effective in your application. The YF is already a big carb for that engine. Low end and moderate rpm operation- no benefit in a larger carb. IMO.

 

[sixtseventwo4d]

The O-P is using two group 31 marine batts and depending how far they are located I recommend 4 ga wire for alt to battery charging if he goes to the high output alternator. 10ga would not allow heavy charging without becoming compromised

 

[Frank]

The O-P is using two group 31 marine batts and depending how far they are located I recommend 4 ga wire for alt to battery charging if he goes to the high output alternator. 10ga would not allow heavy charging without becoming compromised

 

[aussie7mains]

Lived near Crested Butte, Colorado in the 1980’s while running a job, and I can tell you that propane goes back to liquid when temperatures go down to -44 degrees F. All forklifts that were used outdoors were gasoline powered. “Not Propane“.

We’ve seen temperatures below -40 F. regularly at the lower elevations 8,000 to 9,000 feet. At the time, most vehicles were plugged in to aid in starting.

I did a stupid thing on a closed road during the winter. I wandered off and decided to go exploring with my 1966 International Scout. It looked like a normal snow packed road. But I did not think that there could be feet of snow under the thin packed crust. When I was about a mile in the ground shook some. I stopped and got out and then I realized what mess I was in when I broke through the crust with my foot. I got back in the truck and proceeded to back up, and all of a sudden, he crust broke and the truck sunk down to the floor.

It was one of the coldest nights. It went below -50F. Went back the next morning with six sheets of plywood and proceeded to jack up the truck. Put the plywood under the wheels and thought it would be a piece of cake moving it out. Well, I brought along a can of ether and a large spare battery. That poor slant 4 (1/2 a V8) engine would barely spin over.

I was told I had an hour to get it out of there. If it’s not out, a Snow Cat will be coming down and pull it out. I was told most vehicles normally come out in pieces. Well, I got lucky. The engine started firing on a couple cylinders and I kept the starter going until the rest of the cylinders came to life. I got in the truck and started backing the truck up some and moving plywood from front to back.

While I was doing it. Here comes the Snow Cat. The driver stopped and asked if I would like breakfast at the lodge in town when I get it out. I accepted, and we had a great time sharing our experiences. What did I learn? Stay off roads when signs says it’s closed for the winter. That was one cold and tiring experience I will never forget.

Honestly, from what I’ve been through in different places in the country in extremely cold weather. Stay with gasoline, and have a few cans of ether with you just in case.

When people’s lives depend on engines starting up to get them to safety, they better have a vehicle that is able to start with starting aid in extreme weather conditions. And, propane is NOT a fuel to use in such conditions.

Propane and butane are liquids in the tanks, however when the temperature falls it wont vaporize, so there is no pressure in the tank and the liquid cant for forced out. propanes boiling point is -42c so down there its a problem.

 

[drag-200stang]

Do we know at what RPM this engine is operated at?

 

[DON]

Do we know at what RPM this engine is operated at?

I bet it’s less than 3 grand

 

[63 Sprint]

Here is something to think about.
The 170 and 200 engines from the 1960’s through 1970’s are known for having the timing chain stretching to the point that the engine will run poorly at lower rpm’s. Every 170 and 200 engine I’ve ever owned needed timing chain and sprockets replaced at around 60,000 miles. I had two 170’s and one 200.

If the engine was never taken apart, it might be time to replace the timing chain and sprockets with a good double true roller chain and sprocket set if they are available.