87 Craftsman Racer/Off Roader Project

Hey everyone, I guess you could call me new at this but I've had in interest in tractors and small engines for a little over a year now, ever since seeing fearlessfront's first off road murray video. I happened to have 2 tractors, except one of them I wanted to actually use for mowing. The other one wasn't really good for anything so I figured id rip the deck off, do a pulley swap and put in a new engine. It was an older late 70s/early 80s craftsman LT 8 36 with a frozen up tecumseh and a chain drive setup with a 4 speed transmission, which I wish I would've held onto right about now. I stripped the wiring off, scrapped the engine, took the deck off and powerwashed it. Only things holding me back were that I had no new engine, the ball joint on the pitman arm was worn and popping out, the spindles were stiff so I still couldn't steer it that well, the back tires were flat and eventually came off the rims. The other mower was an 86 craftsman yard tractor with a 16 hp briggs opposed twin, 5 speed transaxle in amazing condition, and a rotted out 44" deck. Unfortunately the deck for the LT 8 doesn't hav e its own clutch system like the one already on there so I really couldn't just mount it on.

So months later, I finally found a tractor with a deck to replace it and the 16 hp tractor now mows my backyard. The donor tractor is what I decided to use for my project.

Its got a 12 horse OHV Tecumseh which actually runs ok but idles weird and a 6 speed peerless transaxle that shifts horribly and has a crack in the upper case. I already did the gas pedal mod hooked up wher the throttle was, I just need to put in a separate choke. I'm still looking around for a parts tractor to get a new transaxle possibly with shift on the side, and a briggs flathead to replace the
Tecumseh. My first serious modification planned is a simple pulley change. I'm thinking about a 1:1 ratio with 5" pulleys so that I don't have to change to a different size belt. The major problems are like always clearance issues. If I swap them out, the belt will rub against the shifter, and like on any typical ayp made tractor, the clutch pulley is ridiculously close to the engine pulley when the pedal is pushed all the way down.




I know this was discussed here before but that's my first obstacle. I think I might need to figure out a way to move the clutch back or even attempt to redesign it. I do anything to avoid welding because not only do I not have a welder, I don't have any experience doing it either, so welding remains left out. I also don't want to reverse the clch either because I like having brakes. (Yes, I got my brakes to work on this thing, lol)

I should have some more pics of it later on, but its in pieces right now.

I would just put a smaler one in the back and leave the frount stock

I don't see why you couldn't reverse the clutch action and still use the brakes... You could do like we did, and replace the V pulley with a flat one and move the belt to the other side, then drill a hole and move the rod that moves the clutch to the other side of the pivot. You would need to adjust rod lengths to get the clutch and brake to work together, but I think it would work.

Actually yeah I wasn't thinking that exactly. I could probably still reverse the clutch but I think I would have to find a different spot to put the spring so that it pulls it in the opposite direction. Of course I might need to keep the engine pulley stock anyhow, I can't get it off! Funny because the other craftsman I have is a year older and has been kept in worse condition and that pulley came off easy, plus the OLD LT8 has been even worse and came right off. I'll have to see if I can heat it and then pull it off again. The reason id rather not leave it stock is because putting a small pulley on the trans makes the belt too big, and I still want more contact area on the pulleys for the belt. That and I already would need to make clearance for the shifter, it would be worse with a much smaller pulley.

JonnyBriggs wrote:

Its got a 12 horse OHV Tecumseh which actually runs ok but idles weird and a 6 speed peerless transaxle that shifts horribly and has a crack in the upper case. I already did the gas pedal mod hooked up wher the throttle was, I just need to put in a separate choke. I'm still looking around for a parts tractor to get a new transaxle possibly with shift on the side, and a briggs flathead to replace the Tecumseh.

Personally I wouldn't replace the Tecumseh OHV with a Brigg flathead. The briggs flat doesn't have the same torque as the Tecumseh OVH and wouldn't pull you off the line as well.
The Tecumseh would also be better at high speed.
Just my opinion and that of members of the British Lawn Mower Racing Association.

It's mainly just a personal preference, briggs engines have been a bit friendlier to me in the past than tecumseh engines have. (lol) But considering that it'll be quite some time before I find another engine, it's a great engine to work with over that time.

Well I don't see myself doing much else to it since I'm going to have to start thinking about how I'm going to be able to reverse the clutch direction, not to mention I can't get the pulley off to replace it, and I also don't have the pulleys to begin with. Plus I'd rather put my time and effor towards repainting the parts on the grass cutting tractor.

In the mean time, It was rather inconsiderate of me to not post some pictures of the actual ride:



Here's the engine:


As you can see, I already have a gas pedal hooked up. I just need to get a cable routed to the choke somehow, on these tecumseh's it's a bit hard since this one doesn't have the arm sticking out to hook a cable to; it's on the inside.
Here's how I put the cable in, it's where the throttle used to be. I took a small electric terminal and bent it to lock onto the cable so that it doesn't fray or fall out.


I also have a video looking over it and running:
https://www.youtube.com/watch?v=QfHMt82-BS4&t=2m41s

Thats the problem i had when i tweeked my 85 LT12 - used a 6" motor pulley and clutch idler would contact it with a screech - it went back to normal after i destroyed the original trans ( forgot to clean the inside out and replace grease).

You could look at how race tractors make clutches - this is one for an older craftsman:




Ive been looking thru heymow.com for years trying to get ideas to build a tractor - w/o signing up either - if they dont like non racers - then at least i can get some ideas for my own stuff. Probably would hurt to look around there for a good setup.

You can do What I did. I replaced the engine pulley with a 3" or 4"(I think) pulley, just barely fits. I can disengage the clutch, but if I push it as far as it goes, it'll hit the engine pulley. To take up the belt slack, I used the mower deck's two idler pulleys and the mounting brackets and bolted it to the bottom of the tractor. I also put a smaller pulley(2" I think) on the tranny. Now, I can go almost 20mph, a nice all around speed for a farm use tractor. It's useable for farm chores, yet you can still have fun with it and get from one place to another in good time. It has good low end speed. Reverse, however, goes much faster than first gear. More like second gear.

Your lucky the engine in your craftsman runs as good as it does. My craftsman has the same engine and it runs terrible. It doesent idle, needs choke off and on, surges. back fires, over heats and floods if i dont turn off the fuel. When i got it it was covered in oil. I think it flooded and the gas got into the oil and overfilled the oil which made it come out the vent tube in the carb. I wish i had some pics of it. It was so covered you couldent even read the labels on the engine. Also when i got it i cleaned the carb. It probably needs to be cleaned again but i will wait until it does not run any more. I dont plan on this engine lasting very long since it will burn all of its oil in a few days of use and it constantly over heats. Ive always changed the oil and taken care of it but ive only had it for a year.

Reversing the clutch isn't as hard as it sounds. We drill a hole on the arm on the opposing side of the pivot, bend or replace rod to connect it, replace the pulley with a flat one since the belt goes on the other side, and change the direction the spring pulls. The brakes should not be difficult to modify/adjust as they are still attached on the part of the linkage that moves in the original direction.

One benefit of this (other than clearance) is that when the clutch engages, it wraps the belt more fully around the engine pulley rather than just tightening the belt, which reduces slippage.

Red arrow shows where the linkage originally was connected, green arrow shows direction the clutch now engages.