Model L and Model C Repower Parts

[RichardTX]

The 5000/Pro hi-lo planetary is not as strong as the original L planetary but iut is good enough. I have a 5665 that has 3000 commercial hours on it. The bushings were worn and the ring gear noisy but that is it. Gravely thought that the new style planetary was strong enough to handle 16 HP. To date they have been right.

 

[johnny1953]

getting ready to do my 2nd repower, I'm picking up a dead L8 Gravely that the engine is wore out on. That way it will live another life instead of being parted out.

 

[RichardTX]

The last time I priced out a modest repower, I could buy a low hour Pro8 for less...and so I did. I bought a low hour Pro8 with 30" deck and sulky for $350.

I also priced out a 16 HP Vanguard repower. By the time I figured in the exhaust system, engine, adapters, wiring, ignition switch, etc etc, I could buy a Pro16 for less so that is what I did.

There is a down side to the old L planetaries and new engines. That planetary was designed around an engine that spun at a maximum of 2400-2600 RPM. Modern engines spin at 3600 RPM which means that the ground speed and attachment speed will be about 50% faster.

Lowering the governed RPM isn't really an option. If a modern engine is reset to a maximum of 2600 RPM the power it can generate generally drops dramatically. Typical is a 30% loss in power. That means that a 12 HP engine will only produce 8 HP. Having said that, a new 12 hp engine producing 8 HP@2600 RPM will outperform a worn out Gravely engine. I would venture a guess that most old worn L engines are actually producing about 4 HP...maybe less.

It is these all of these issues that caused me to dump the L8 (Super Convertible) I had. I would get all done and still have the same failure prone PTO linkage, the same battery box and hood issues and more.

Don't forget to add a dipstick and increase the amount of oil in the transmission.

My advice is to weigh the pros and cons carefully before starting a project like this.

 

[wainemaine]

The 13 HP ?Honda clone has max torque at 2500 RPM, and is pretty flat up to that. 13 HP Gas Engine With Recoil Pull Start : Carroll Stream Motor Company : www.carrollstream.com Torque determines the "work " a engine can do. HP is how fast it can do it. No one cares how fast a tractor is, they used to be rated by "drawbar Pull". There is an old racing adage that says " torgue wins races and HP sells cars", thats why you never saw a 1.6 L engine in a race pontiac GTO or chevy chevelle. Even tho back in the 80s Toyota had formular atlantic engines that produced 900 HP and up. All that said the Honda clones come with wiring, a switch, and everything new and the efficiency of a new cross flow overhead valve head sips fuel compared to the old flat heads, I would bet the gas savings at over 15 bucks for 5 gallons would more than pay for the adaptors over the life of the engine. 100 gallons doesn't take very long if it's working every day.maybe 200 hours at working throttle speed ? And... it sure is nice running at 3600 throwing 2-3" of snow 75 feet at a very fast walk/ slow run. Or a regular weekly mowing job done in 1/2 the time.with a 42" instead of a 30"deck.all the while still using less gas! I maybe would have bought the pro 8 for 350 bucks too, ran it till it blew up and then dropped in a honda/ honda clone and never looked back. But more likely I would have bought yer old blown up gravely for100 and dropped in a new jap engine and started enjoying the fuel savings and reliability right away. and sold the old engine for 100 bucks as a rebuildable core to someone that just has to have an original, gas guzzling ,quirky,antique, trailer queen.

 

[RichardTX]

The 13 HP ?Honda clone has max torque at 2500 RPM, and is pretty flat up to that. 13 HP Gas Engine With Recoil Pull Start : Carroll Stream Motor Company : www.carrollstream.com Torque determines the "work " a engine can do. HP is how fast it can do it.

I can find no torque/rpm chart for the Chinese engines. I can only assume that the torque curve is the similar to a Honda. According to what I see on Honda engines, the torque curve actually drops off above 2500 RPM. It may be OK when run at 2400 RPM. Hard to say without some evidence.

I will concede the power point in this case but I do appreciate the link to the 13 HP Chinese engine. I have known about Carrol Stream engines for a while. I am more than a little skeptical about them. I cannot find any longevity data for those engines. I do foresee some problems with them as the cooling fan is made from a white plastic. As a general rule, white plastic does not hold up to sun light and will get brittle and fail is short order when compared to black plastic. In general I fall back on the adage that states "You get exactly what you pay for" and "quality comes at a price".

Just to give you an idea what $350 will buy, here are some purchases I made this year.

- A 16G with 50" deck for $350 It had dirt in the needle/seat.
- A Pro 8 with 30" deck and sulky for $350 (including gas to pick it up) It needed a battery.
- Two 4 wheel tractors for $350. One is a 8129 and the other is a 8162-B. Both came with good/fair 50" decks. Both of them run well. I had to put an exhaust valve in the K301 before it would run well. All I did was put gas in the 8163-B and it ran.
- I can't remember what I paid for my 5665 with steering brakes. I think I paid about $400 for it. It needed a new condenser.

Now you see why I dumped the L8. When I can get a newer tractor that runs for about the same money as an engine, it makes the L8 not worth messing with.

For the record, I traded the L8 for a old style brush. I didn't want to part out the L8. Had I done that I would have been left with a large casting and a bunch of parts that I would have to take to the scrap yard and that is a pain.

 

[RichardTX]

I just checked CL and found a fellow selling two L tractors for $100 each. The tires and wheels even look good.

2 gravely walk behinds

 

[wainemaine]

I have 3 carroll stream engines, a 13 HP on a professional 12 gravely used mostly for snow blowing and brush cutting 3 years and going at temps down to - 20F(adapted with Bruce's help) , a 16 single cylinder that replaced a 20HP 2 cyl briggs on a sears lawn tractor used mostly as a Tug / box scraper, and a 16 that replaced a 18HP briggs twin on a leaf vacume / trash blower 12" vac thing, that runs 8 hours a day for 2 months a year( it's 2 years old). I don't use Stabil ( I shut the fuel off and run them dry) and they all always start and fuel use on all of them is less than before I swapped. I have no problem with carroll stream engines and parts are interchangable with honda at any local honda dealer, the colors are even the same. I have never even changed a spark plug, just oil. I see no dif. in the 16HP CS and the 18 and 20 HP B&S they replaced, and at the price I can buy more than 2 for 1.

 

[wainemaine]

I wouldn't buy them for 50 bucks unless I was going to repower them. the Ls used gas like a toilet flushing.

 

[RichardTX]

I wouldn't buy them for 50 bucks unless I was going to repower them. the Ls used gas like a toilet flushing.

I wouldn't say that. If I recall correctly, I could get about 5 hours of running time per tank of gas (2 gallons) using my Father's L tractors. This was cutting heavy grass with a 30" deck. I would start about 9am with a full tank, run it until noon, break for lunch, then run it for another hour or so before it would run out of fuel.

 

[Tenn_Blue]

I've got a "project" L sitting in the barn, that I want to repower eventually, so follow these repower threads with interest....

Haven't worked all the details out yet, but have been thinking about adding a reduction gear set between the "modern" engine (I would choose a diesel clone) and the gravely transmission. Add a 2" or so oil filled gear case with set of gears or chain/sprocket in an oil bath at say a 35% reduction in speed throughput.
That would lower the ground speed in low range of an L model, and make the high speed (which is usualy too high for most tasks anyway) more usable, and at the engines designed rpm band. You could also offset the engine up, down or over if desired.
Down side would be a similar reduction in the pto speed, but that shouldn't hurt anything except a cutter deck?

Presently working on a diesel repower of a Deere zero turn M665 and a couple other things, but hope to putter around with this some more soon.... Any thoughts on if this would work? (the Gravely, not the zeroturn - I KNOW that will work! )

Oh and the other Gravely project is adding steering brakes to the L!

 

[Oneaxepony]

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.

 

[RichardTX]

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.

 

[wainemaine]

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.

 

[RichardTX]

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.

 

[Tenn_Blue]

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!

 

[RichardTX]

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.

 

[gravelymay]

C10A and later

 

[johnny1953]

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.

 

[johnny1953]

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

 

[Oneaxepony]

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.