[24] TechnoChicken's "Dave the Democrat"

#Buildoff2024

Hey y'all, haven't really been around real proper for a while, but I picked up this sears ST 16 for FREE a few months ago. Had a broken rod (Tecumseh Special) apparently it leaked oil so bad it dried up and shredded itself right good. Been sitting in the lot since before Christmas, yesterday I found a 420cc powerfist china clone engine for it for only 50 bucks, and a set of ATV tires for 90 bucks (I was in a rush and could have talked him down way more if I was smarter but you live and learn. 420cc motor had no room for wiggle as I was first out of 50 or so people who messaged the guy.

Anyway got plans to plumb the motor up, put some ATV tires on the rear and snowblower tires on the front (I got contacts for some real cheap ones but 30 minutes west and I'm never really down that way, might have to dedicate a trip)
I have a winch kicking around here somewhere, pulley setup I'm thinking 8" to 4", maybe 3" hoping for around 40kph (25mph for yanks) @mightyraze, do you know if these rear pulleys are tapered, and if 8-4 (front to back) should be good for 40kph?

Also will probably throw some paint on her, maybe just the rims? Maybe the body. Not sure about brakes quite yet, will def. want to put them on a separate pedal for easier shifting, nicer not to have to try to find clutch point on these unsynchronized transmissions. Usually I end up towing 600+ pounds (what the wheelie horse was subjected to) so would be really nice to be able to shift properly.






Samsung pictures are horrible will post some proper ones when I drag the DSLR out there

Approved Mightyraze 2/28/24

[adm]Welcome to the build-off!
[/adm]

@TechnoChicken , Yes, the 633A (true 633a in that one) will be a taper shaft for the input pulley.  Probably not one you can drill the hub out on top of that.

8 Front and 4 rear might get you close depending on the RPM you are going to make that engine scream.   More I think of it maybe more as I had a 8 and a 7 gave me 15-16.  Same with a 7/6.   I am not certain on the speed as I have not tried that combo with the 633.

What's model # 917.25xxx I'm guessing a 72-73 maybe a 74.

MightyRaze wrote:

[adm]Welcome to the build-off!
[/adm]

@TechnoChicken , Yes, the 633A (true 633a in that one) will be a taper shaft for the input pulley.  Probably not one you can drill the hub out on top of that.

8 Front and 4 rear might get you close depending on the RPM you are going to make that engine scream.   More I think of it maybe more as I had a 8 and a 7 gave me 15-16.  Same with a 7/6.   I am not certain on the speed as I have not tried that combo with the 633.

What's model #  917.25xxx  I'm guessing a 72-73 maybe a 74.

Thanks man, it's good to be back, I will check the serial at some point, where is it located on the tractor?

I don't usually like to cruise over 4000 rpm, it's fine for a couple of seconds but I don't like to scream down the street for long periods of time at high RPM

Sounds like getting a rear pulley on this is going to be a challenge, they really don't make these sears easy to work on lol, this trans looks like it's going to need to come out to get the rear pulley off.

@mightyraze One thing I noticed is the front clutch pulley, is on an angle, have you seen this on other sears, and is that normal?

TechnoChicken wrote:

Thanks man, it's good to be back, I will check the serial at some point, where is it located on the tractor?

I don't usually like to cruise over 4000 rpm, it's fine for a couple of seconds but I don't like to scream down the street for long periods of time at high RPM

Sounds like getting a rear pulley on this is going to be a challenge, they really don't make these sears easy to work on lol, this trans looks like it's going to need to come out to get the rear pulley off.

@mightyraze One thing I noticed is the front clutch pulley, is on an angle, have you seen this on other sears, and is that normal?

Serial should be between the shifter and the seat unless the plate has been removed.

More I think about it, you should be pretty close to your goal on speed.  I was thinking I made over 25 I think with a 10inch and stock 8.  So I think you may be good.

Some of the rear pulleys are spot welded and the hub can be drilled out and rewelded on a new pulley.  Shoot a pic of that when you get to it.  Should be easy to tell the difference between the (6 welds vs single weld around the hub).

Post a pic of the clutch. Unless it is older, the clutch should be hanging from the battery tray.  

Like this...  (sitting on the engine plate  upside down, not the best pic)  Also, you can see the silver plate below my shifter is where the model is.




I had to trim a couple inches off the tray for my 389 to fit in.

MightyRaze wrote:

TechnoChicken wrote:

Thanks man, it's good to be back, I will check the serial at some point, where is it located on the tractor?

I don't usually like to cruise over 4000 rpm, it's fine for a couple of seconds but I don't like to scream down the street for long periods of time at high RPM

Sounds like getting a rear pulley on this is going to be a challenge, they really don't make these sears easy to work on lol, this trans looks like it's going to need to come out to get the rear pulley off.

@mightyraze One thing I noticed is the front clutch pulley, is on an angle, have you seen this on other sears, and is that normal?

Serial should be between the shifter and the seat unless the plate has been removed.

More I think about it, you should be pretty close to your goal on speed.  I was thinking I made over 25 I think with a 10inch and stock 8.  So I think you may be good.

Some of the rear pulleys are spot welded and the hub can be drilled out and rewelded on a new pulley.  Shoot a pic of that when you get to it.  Should be easy to tell the difference between the (6 welds vs single weld around the hub).

Post a pic of the clutch. Unless it is older, the clutch should be hanging from the battery tray.  

Like this...  (sitting on the engine plate  upside down, not the best pic)  Also, you can see the silver plate below my shifter is where the model is.




I had to trim a couple inches off the tray for my 389 to fit in.

Ok, will grab a picture of the clutch, I am working on pulling the trans right now, went to drain the gear oil and it looks brand new, thinking the guy before me musta kept up with maintenance. I drained a bit out so will need to add some in, do you know off the top of your head what kind of oil to put in there (assuming 80w90) and how to tell when it's full?
And yeah, will be having to trim the battery tray a bit, will probably have to remove the fuel tank on the new engine

It takes 30W non-detergent.  There should be a fill above the axle left side.  When you see it there, it's full.

Old 633A manual says 5qts.  Newer Craftsman manuals say 4qts.  Take your pick.

Since you are changing the oil while out of the tractor, if you do not want to take all day to fill it.  Pop the shifter out and fill it there.  **Put the trans shifter in neutral first for easier reassembly.

MightyRaze wrote:

It takes 30W non-detergent.  There should be a fill above the axle left side.  When you see it there, it's full.

Old 633A manual says 5qts.  Newer Craftsman manuals say 4qts.  Take your pick.

Since you are changing the oil while out of the tractor, if you do not want to take all day to fill it.  Pop the shifter out and fill it there.  **Put the trans shifter in neutral first for easier reassembly.

Thanks man looks like someone put a little 90 degree pipe in the filler hole to make it easier to fill, I'm thinking the clutch is supposed to be like that, it makes the belt line up better

I actually don't think I will change all the oil as it looks very clean, (unless there is a reason I should... never know) just have to replace the little bit that I did drain

Done today
-battery tray trimmed
-wiring done
-tires mounted
-trans pulled
-sorta got the trans pulley separated from the hub
-tightened up ball joints, stopped steering wheel from falling off

Probably something else, will do a pic dump tonight when I get back from town with parts

TechnoChicken wrote:

Thanks man looks like someone put a little 90 degree pipe in the filler hole to make it easier to fill, I'm thinking the clutch is supposed to be like that, it makes the belt line up better

The old ones came with that 90!

Welcome to the Build Off!

The later rear pulleys were smaller than the earlier ones, with a 8" front on an ungovernered engine 25mph is about what you'll get. My friend hits 26mph with that exact tractor and setup.

Didn't end up getting parts tonight, but I did get the promised pictures

Modified Battery tray (just basically hacked it apart with the grinder, it's plenty thick enough, shouldn't mind at all)




Motor with removed fuel tank & goodies


We have an old snap-on tire machine at the shop so got these ATV tires mounted up in no time
Didn't balance them though, you guys think that's needed, I'm not sure if you usually balance ATV tires or not.






Old tires, pretty sure they might actually be factory, they say "sears" on them and are cracked as hell so might be 50+ years old? (If so they popped right off with no trouble at all, so hats off to sears for making a tire that holds air after 50 years)
Don't have a pic but fronts look brand new, this thing was well taken care of.




That hub bit that I knocked out



The tranny (Wonder if the word filter lets me say that...)


Serial number




@mightyraze , here's that clutch pulley thing I was talking about, not sure if you've seen it on any of your sears or if that's bent up?



Anywho, going to try to grab some parts tomorrow:

-Rear pulley (4"-3 1/2")
-Engine mounting bolts
-30w gear oil (I'll check if I have some in the shop)
-Diode (I more or less cut the one off the 420cc way too short so will have to find a new one)

Will post a running tally of what I spend on this

No need to balance the ATV tires.
You got yourself a 1973 ST/16.
That clutch mount is pretty bent. Pulley should be straight up and down.
Best pic I have.

MightyRaze wrote:

No need to balance the ATV tires.
You got yourself a 1973 ST/16.
That clutch mount is pretty bent.  Pulley should be straight up and down.
Best pic I have.

Is that an opposed sears tho? Wondering if the tecumseh models were supposed to have that as it looks like the belt won't line up right if I straighten it out?

TechnoChicken wrote:

Is that an opposed sears tho? Wondering if the tecumseh models were supposed to have that as it looks like the belt won't line up right if I straighten it out?

Nope, 16HP Tecumseh model.  ST/16 like yours.



More shots of the clutch parts

MightyRaze wrote:

TechnoChicken wrote:

Is that an opposed sears tho? Wondering if the tecumseh models were supposed to have that as it looks like the belt won't line up right if I straighten it out?

Nope, 16HP Tecumseh model.  ST/16 like yours.

Thanks man, I had a look at your pictures and thought about it a bit and decided to straighten her out with the torch. She's all straight now, thanks for your help.
Not really even sure how that ever got like that though, that is quite a bit of an angle

Done Friday and Saturday
-Straightened clutch pulley
-Fixed charging diode
-Mocked up belt guards
-Made rear belt guards
-Mounted transaxle
-Bought a whole bunch of hardware
-Charged battery that came with the tractor, still had 7 volts, (Key left on) is only 2 yrs old
-Sorted out rear pulley

Alrighty fellers, got most things all sorted out, SHE RUNS absolutely ridiculously fast, does wheelies without me even needing to shift my weight, this 420cc PULLS. had to do some belt monkeying to get the belt to stop spinning (will post up some pictures)
Might make a quick video of me smoking my neighbor's Bolens ST160, and a speed clock, feels like our target goal of 40 km/hr IN SECOND GEAR! 3rd gear doesn't really feel that much faster because the motor bogs down.

@mightyraze, I think you put a very similar engine in your sears, how did you make the hood fit? mine def. will not be wanting to do that.

I don't remember if and how much bigger a 420 is from a 389/390.  With the engine gas tank, I had to move my lower grill forward to clear the carb.  I also had to raise the engine about 1/2 inch.  I also put in a spacer to lengthen the ST hood about 2 inches.

https://www.atltf.com/t5585-mighty-s-1975-st-16-restore

I later modded it for a pulse pump and removed the fuel tank from the engine.  I also put in about a 5 degree tilt that allowed me to put things in a more "stock" location.

https://www.atltf.com/t6081p175-ol-sears-1975-sears-suburban-st-16#127284

You can see in the 3rd pic in that post some of the extra holes I added for the lower grill to help make it fit.  I have heard some that have access to SS hoods and riser for the lower grill have used those.

Clocked the old girl at 50km/h (43 in 2nd gear) today, cruises pretty nice down the road, lot of steering slop keeps you awake for sure!
There is an issue however, with the belt overheating, on the way back after about 2 minutes of driving, the belt was slipping like crazy, and I only got to about 38 km/hr in 2nd gear, and could feel the belt slipping a lot.
You guys know how to keep the belt cool so I get good grab all the time? I'm running an 8 to 3 pulley swap with 5/8 pulleys and a 1/2 belt (Should went with a 9 to 4,( the engine doesn't even have enough power to max out 3rd gear))
you think the holey pulley mod would help keep it cool?
Ideas? Querys?

Holey pulley may work against you in speeds like that.  3inch holey pulley would probably chew it up.

Probably getting hot and stretching like you said.  Clutch spring good?  Maybe an idler topside to get more belt wrap on the transaxle?

MightyRaze wrote:

Holey pulley may work against you in speeds like that.  3inch holey pulley would probably chew it up.

Probably getting hot and stretching like you said.  Clutch spring good?  Maybe an idler topside to get more belt wrap on the transaxle?

It might be a good idea, the belt also has troubles clutching when hot, none when cold though?

The belt shouldn’t get that hot anyway, sounds like you need more belt tension or more wrap on the pulleys.

RichieRichOverdrive wrote:

The belt shouldn’t get that hot anyway, sounds like you need more belt tension or more wrap on the pulleys.

I have good wrap, I guess that much heat is probably due to slippage so avoiding slip should keep it cool. That being said the trans and engine get quite hot and transfer heat to the pulleys.
Belt is still touchable for about 10 seconds before becoming uncomfortable.
Rear pulley is touchable for about 1/4 of a second lol.

Not really surprised at all that a 3” pulley gets hot. I’d try more belt tension. Friction from the belt will usually make more heat than what the engine transfers to it through the crank. Most of your clutching slippage should be at the engine pulley, if the belt is moving then the trans pulley should be moving. Only time the belt should slip at the trans is when you’re rolling in gear with the clutch pushed in, so the trans pulley should stay fairly cool. I was just looking at this yesterday on the lawn ranger, the engine pulley was pretty hot but the trans pulley was just warm.

RichieRichOverdrive wrote:

Not really surprised at all that a 3” pulley gets hot. I’d try more belt tension. Friction from the belt will usually make more heat than what the engine transfers to it through the crank. Most of your clutching slippage should be at the engine pulley, if the belt is moving then the trans pulley should be moving. Only time the belt should slip at the trans is when you’re rolling in gear with the clutch pushed in, so the trans pulley should stay fairly cool. I was just looking at this yesterday on the lawn ranger, the engine pulley was pretty hot but the trans pulley was just warm.

Will do, either I need a better spring, or the clutch is bottoming out I will try to look at that this afternoon.
Not sure if this is normal with these trannys but this one (633a?) gets pretty warm after you drive it for 10 minutes or so at high speed.

Other thing for guys that run these unsynchronized transaxles, I have to whip this thing pretty hard to get it to shift, any tips on shifting these? You double clutch? let off the throttle before shifting? Hold er to the floor through the shift?