Model L and Model C Repower Parts

   / Model L and Model C Repower Parts #31  
I've got a "project" L sitting in the barn, that I want to repower eventually, so follow these repower threads with interest....

Any thoughts on if this would work?

I repowered a C8 with a 13HP Honda clone. I dont find the engine speed to be an issue as it has plenty of torque at lower rpm. That said, I've often thought about how to use gearing or chain and sprockets to allow the engine to run at 3200+ rpm while keeping the input to the drive pinion at 2600 rpm. To me, gearing would be more difficult than chain and sprockets. I used the front half of the Gravely crankcase (2 1/4 inches deep) with an adapter plate behind it on my repower. To use chain you would have to put a sprocket on the drive pinion in the front half of the crankcase. The engine would have to mount on the adapter plate such that the crank is above the drive pinion sprocket. Speed reduction would be determined by the ratio of sprocket sizes on the crank and drive pinion. The lower sprocket and chain would bathed by oil in the front half of the crankcase. The engine crank and sprocket would have to be enclosed to keep oil from flying everywhere. The engine would mount higher than normal so there would probably be interference from the handle bars requiring modification. The higher engine would have better ground clearance (a plus) but the tractor would have a higher center of gravity (a minus).

Because there are so many issues to work out and the fact that I already have a working tractor, I have not tried this. However I would never discourage someone from trying it as you may end up with something that works well and that the rest of us can learn from. Good luck with you project.
 
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   / Model L and Model C Repower Parts #32  
I repowered a C8 with a 13HP Honda clone. I dont find the engine speed to be an issue as it has plenty of torque at lower rpm. That said, I've often thought about how to use gearing or chain and sprockets to allow the engine to run at 3200+ rpm while keeping the input to the drive pinion at 2600 rpm. To me, gearing would be more difficult than chain and sprockets.


Gearing is a piece of cake. Install the two gears on the crank, install a two speed planetary and ring gear and it is done.
 
   / Model L and Model C Repower Parts #33  
I must be missing something , I don't see the need to run a much more powerful engine at 3200 if you have more power at 2600 than you ever did ! If a 13 HP isn't enough for what you plan to do, stick on a 16 HP clone for 40 bucks more . I got a 16 on a regular lawn tractor and its a bulldozer grading with a box blade idled down.
 
   / Model L and Model C Repower Parts #34  
I must be missing something ,


The OP said "I've often thought about how to use gearing or chain and sprockets to allow the engine to run at 3200+ rpm while keeping the input to the drive pinion at 2600 rpm.gearing would be more difficult than chain and sprockets."

I was explaining that it wasn't. The reverse is actually true.

As far as power goes, there are certain operational conditions where a 16 hp equipped Gravely would run out of power.
 
   / Model L and Model C Repower Parts #35  
I had started the idea of gear reduction a while ago before Gravelymay was providing his most helpful parts! At the time, one of the "hot setups" was to use the parts of the original lower case (and unique sun gear) to mate up the new engine.

I started thinking at the time that I could cast a thin gearcase that used the original parts and had the reduction set (as explained - really easy, just 3 gears). Just never got out of that mindset, I guess...

While you can throttle the engine down, operating it at it's peak performance increases efficiency.

At the moment, I really don't "use" my Gravely (an L) all that much, this was more an engineering experiment. I used to use the Gravely a lot - mostly on slopes and area I wasn't comfortable taking the tractor. That was also why I coveted steering brakes!!! But as I get better on the tractor, those Gravely areas get smaller!
 
   / Model L and Model C Repower Parts #36  
Gravely put a two speed planetary on the C10 and later tractors. There is a total of 6 gears on one planetary. There are two gears on the end of the crankshaft and a common ring gear.
 
   / Model L and Model C Repower Parts #38  
I like the old L planetary's they seems to be Stronger, I'm currently repowering a 1973 C8 with a 15 horsepower Lifan it will look like a 5000 series.
 
   / Model L and Model C Repower Parts #39  
I just got my 1973 C8 going this past weekend, I used a 15 Horsepower Honda Clone & the tractor has unreal power compared to what a Normal L/C 8 with a 7.6 horsepower engine on it, Until you have tried one of theses repowered tractors that were headed toward the scrap pile, You don't know what you are missing
 
   / Model L and Model C Repower Parts #40  
Congratulations on your repower! It can take a tired old machine and give it new life. Can you tell us how you accomplished the repower? Did you work with Bruce to get the appropriate adpater plate(s) & parts or did you use some other method? Thanks.
 
 
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