Long belt OK?

I’m planning a rat rod wheelbarrow bucket T kart for my grandson. It will be based on a Craftsman LT1000 with 18 HP Briggs engine and MST-206 transmission. The only change to the drive train I plan is a 5.5” drive pulley. I want to stretch the frame quite a bit. My rough calculations say I’ll need about a 130” long belt.

The question is... is this long of a belt for a kart OK? I don’t want to complicate the build any more than necessary.

Thoughts?

(I’ll be starting a build thread soon. I hate to start a thread and then not be able to follow through on it. The parts pile is growing though.)

Teaser pic... I stripped the donor frame (it will provide the ‘stretch’)

If I were you I would go with a Jack shaft I have no idea how you would go about setting that up but it sounds like a good idea to me

I have a 107 on mine, which is the longest 1/2 inch belt TSC stocks

Fastman wrote:

If I were you I would go with a Jack shaft I have no idea how you would go about setting that up but it sounds like a good idea to me

I believe @Nevadablue said he was going to lower the tractor so I’d say stack two pulleys on a 5/8 shaft and add a couple pillow blocks. Thus allowing for the transaxle to sit higher in the frame and allowing for two shorter belts. It would also mean that the clutch system wouldn’t need to be reengineered depending on where it was mounted.

I had planned to lower, but am reconsidering that. I have found long belts that are readily available, but now I have to study this.
Originally I did plan a jack shaft and may still need to do that. The LONG belt is sort of putting me off.

I just looked at a bunch of pics of my donor machine and have an idea. Since I will be using the original drive pulley (moving the big pulley up on the sleeve), I can put that one where I want it. If I make it 2” or so lower than the existing pulley, I can then put a jackshaft UNDER the frame deck at about the place where the transmission driven pulley was. That makes for a ‘normal’ belt length. I will of course have to lower the clutch assembly/pulleys. But that means no redesign, just some fabrication... I think. It is so darn hot here, I can only work out there for a few minutes at a time, so for now, planning is it.
Then I can build a belt tensioning setup for a short rear belt.
Thinking... I really want the top of the frame to be flat and clear so the wheelbarrow tub can sit right on it.

Looking at this pic and the parts diagram, it appears that longer bolts for the tensioner and idler, a longer spacer for the tensioner and reworking of the belt guards will do it. I’ll have to rework the guards anyway with the larger pulley. My plan is to cut the lower drive pulley loose and move it up the sleeve and weld.

What if... I used this assembly as a jackshaft? It is one of those variable pulley things. I could lock the pulley so it doesn’t ‘vary’ and make a cross member to mount it on. It looks to be exactly what I need.
Ideas?




Edited to revise image above.

I had thought about the varidrive pulley as well. And as he gets used to the tractor, you can move the pulley to up the speed without having to change pulleys and belts. Just add a few different holes to mount the varidrive pulley so you’ve got some options. That would work great I’d think

I've been told that varidrives don't always play well with pulley swaps, but it could be set up to have a similar ratio but the input would be overdriven. Personally I don't think that you would have any problems setting it up like you described.

So, some measuring, head scratching and thinking. Now I’m tired. But...

It looks like I can leave the existing drive pulley like it is for now. If I can figure out how to lock the vari-drive and keep it from being variable, I can get the RPM to the transmission input to about 1000 RPM. They are rated for 2000 or 2500 I think. And, IF I get the variable doodad set up right, I can vary it manually and set the input RPM up to 1500 or more with no pulley changes.

This can work, now the old engineer brain has to study the vari-drive after the old man gets it out.

Did I say it is HOT out there?

(I edited the post with the vari-drive pic to reflect better measurement)

question are you going with a gear drive or hydro rear end???

The main donor machine has an 18 HP Briggs and an MST-206 transaxle. I will be using those. I still need to fire up the engine and make sure it is OK. It was ‘not working’ when I got it. Someone had robbed the ignition switch and solenoid. The engine has good compression and the starter works, I did test that with my jump box. Now to kill all the ‘safeties’, pull the plug and see if I have spark. Then check compression and do a quick squirt of gas and see if it runs. If it does, I will start the build thread I think. I don’t have another vertical engine. There are 3 good horizontal Tecumsehs in the parts pile for later projects.

So, with more thinking and a bit of wrenching, I decided that maybe this is the way to go.



I recently got an LT1500 with a blown engine. It has the vari-drive pulley, and the mower deck. The machine doesn’t seem to have been abused other than the engine... LOL

So, I removed one of the deck spindles and I think it will become the jack shaft. That spacer under the pulley slips on. I can cut the other deck pulley to slip over that spacer and tack the pulleys together and the lower one to the spacer. Then I will have a double pulley that fits the splines on the spindle. I can make a cross member and mount the spindle at the spot the transaxle pulley used to be.
It is about an inch and a half or so from the frame to the top of the drive pulley. So, the bottom pulley on the jack shaft can be mounted there and the top one can line up with the transaxle pulley.
Of course this is all easy to say, but I think I have the idea now. Not complicated, uses standard drive belt and clutch with nothing being moved out of place.
Off to the races...

Thanks for the input guys, it helps with the sorting out of things.

In a previous life I was a heavy equipment mechanic in an underground mine. The old mechanic couldn’t resist the suspense any longer.

So, I squirted some ether in the intake of the engine on the donor machine, cranked it with my jump box... one more squirt, one more crank and it RUNS!

So, I’m off to start the build thread for the Rat Rod Wheelbarrow Bucket T Tractor.

Those spindles are pretty much jack shafts....  Only weakness I can see is maybe the casting for the spindle, but it should take some abuse.