Slow mow build

[oughtsix]

I am tired of tinker toy mowers with little rubber band engines that always break.


I am trying to figure out how to attach this:

to this:

I was thinking of pulling the main shaft from this:

and stick it though the hole in the engine it came out of if I can figure out how to get the darned shaft out.

I was thinking of using one of these:

and a pair of these:

but I am not really looking forwards to trying to grind a slot in a hardened shaft.

Then plump the pump to a couple of these:

Any ideas, suggestions or comments?

The pump is this:

For the wheels I have 7cu in, 15cu in, 24cu in and that pair of torque hubs that I was thinking of putting some 30" tires on.

I have the whole 87 corolla the 83K miles engine came out of. The clutch has only 8K miles on it and I would like to use the clutch to unload the engine when starting. I don't like the bastard carb on the engine and I am looking for an ebay carb to replace it without the miles of emissions vacuum tubes. The ignition looks really sweet and I think it is just a 2 wire hookup!!!! I will have to figure out where the voltage regulator for the alternator resides on the car and wire it using the OEM alternator plug.

Final speed will of course be determined by engine speed (goal ~1500rpm), the displacement of the new old stock twin variable displacement pump is 1.15cubic inches max, the size wheel motors I go with and of course the tire size. My thought is to turn the engine slow to get decent gas consumption and also keep her quiet. My original plan was to find one of the 3cyl 1.0l Toyota engines but this one was free.

Suspension is a given and I am thinking air over hydraulic to soften the bumps.

Blades will be driven hydraulically. There is an output hole on the twin var pump for a piggy back pump or two. I have four custom made independently floating mower decks (3 staggered and a spare) made out of a special grade of vulcanized rubber reinforced with steel and nylon belts meticulously crafted by Goodyear. I will wrap these with steel cylinder to keep them from distorting (~24" dia x ~4" high). Should help keep the decks quiet. I might even venture into flail-mower design as they seem to be able to produce a much higher cut quality than I ever imagined when the correct flails are used.


Input PLEASE!!!!

 

[smiley]

More power is always good but large pictures not necessarily so. With dial up, I hardly ever wait the 5-10 min for these huge photo's to load so miss a lot of stuff. Cable wants 3g's to install, no dsl available, so am looking at wireless 3/4g to try to solve the problem.

 

[Snaker]

More power is always good but large pictures not necessarily so. With dial up, I hardly ever wait the 5-10 min for these huge photo's to load so miss a lot of stuff. Cable wants 3g's to install, no dsl available, so am looking at wireless 3/4g to try to solve the problem.

Smiley you to huh? I thought I was the last one on dial up. My computer is full of 50MB plus updates that "failed to install". I had been going to the local library with a memory stick for the big files but they just finished a big dollar remodel. Now their new computers won't allow me to download and save. I think we're obsolete.

 

[oughtsix]

I just removed as much air from the pics as I could find. Posting pics is such a headache. I think I now have as much time into massaging graphic files as I do into pulling the engine last weekend.

My first chore is to put a battery to the starter and see which way the engine spins. Hopefully I will be able to do a direct drive to the pump and not have to use belts to reverse the rotation to match the pump. Hopefully I will get a few minutes this weekend to accomplish this. Unless anyone knows the direction of rotation of a Toyota 4A engine off the top of their head?

 

[o2batsea]

What are you mowing? Elephant grass on the Serengeti? Ling-Ling's bamboo patch?

With so many mowers available in all their wondrous variety I have to ask: why?

 

[beenthere]

Wish you luck. And hope we see it "mowing" someday.

 

[oughtsix]

Doing a little calculation I come up with a drive ratio of:

26" tire, 15in^3 Wheel Motor, 15mph max speed = 2530 engine RPM

20" tire, 7in^3 Wheel motor, 15mph max speed = 1278 engine RPM


The pump is rated at 4000rpm max and 1.15in^3 max. I would guess I should be able to run the pump at ~1500 rpm without any ill effects?

I like the 15in^3 wheel motors better than the 7in^3 motors as they are a lot bigger and a much heavier build.

 

[oughtsix]

What are you mowing? Elephant grass on the Serengeti? Ling-Ling's bamboo patch?

With so many mowers available in all their wondrous variety I have to ask: why?

Sounds like a fair question!

I have about 2 and a half acres of lawn.

I have been through multiple mowers and haven't been very happy with any of them. Started with a JD R75 which took forever and the underpowered 8hp brigs puked multiple times. The lawn tractors are just toys and take forever (Many trees). I had a Craftsman with a 18hp Kohler. Great engine but I think the rest of the mower was made out of tin foil. My current mower is an old John Deere F725 with a water cooled Kawasaki. The original Kaw had many thousand hours on it before it finally gave up so I put a brand new Kaw and have had nothing but problems with the POS. The push rods in the head start sticking and binding then bending. Much research turns up a whole bad run of the Kaw engines and small engine warehouse says "not their problem!". So why gamble another ~$1000 on another Kawasaki when I know they have no qualms about selling screwed up engines???

The residential zero turns are just cheap junk. The commercial zero turns are many thousands of dollars and the engines are no better than my Kaw unless I want to spend $10K+ for a diesel.

Screw it! I will build my own! I picked up the pump for $100 + close to that again for shipping. (I believe the pump is a near $5K part). The wheel motors are all new and were all less than $50. The torque hubs with integrated brakes were less than $100 for the pair (+ shipping, of course). Like I said I really wanted a 1 liter 3 cyl Geo engine or Japanese 3 cyl diesel but the Toyota 4A was free and runs great!

Most of all I want to play with Hydraulics and learn something along the way! Yep, I know the hoses and plumbing are going to cost more than a new lawn tractor but hey a new lawn tractor is probably 75% profit along the chain anyway!... that doesn't leave much for quality parts! If she runs some day I will at least know what parts went into the contraption and how to fix it! I figure a 1.8 liter 4 cyl running ~1500 rpm might survive more than a few seasons after which I might also have some hearing left!

The "Slow" means it is going to be a slow build! I don't foresee having her on grass this season.

 

[o2batsea]

Only thing that I can see that will be an issue is engine cooling. I think that's why most lawn mowers are powered by air cooled engines. You'll have to have a pretty substantial radiator and fan plopped somewhere on your rig, since the vehicle will be moving pretty slow all the time.
Best of luck with your build.

 

[oughtsix]

Only thing that I can see that will be an issue is engine cooling. I think that's why most lawn mowers are powered by air cooled engines. You'll have to have a pretty substantial radiator and fan plopped somewhere on your rig, since the vehicle will be moving pretty slow all the time.
Best of luck with your build.

Yes, this is one area that I haven't figured out in my mind yet. How to mount the radiator. I will use the radiator out of the Corolla. It has 2 motorized fans and appropriate shroud since the motor was a transverse mount. It also has a huge AC cooler mounted in front of the radiator which I hope to re-purpose as a return line hydraulic cooler.

I understand your air flow concern being the mower will be a slow moving rig. My thinking is power = heat. The power demand on the engine should be WAY less than it was designed for... hopefully heat will be proportional. Slow RPM's should also keep the cooling requirement down. Mounting the radiator will be interesting. I am hoping to figure out how to mount it above the motor blowing down onto the mower. Grass clipping buildup will of course have to be monitored. Hmmm.... maybe blowing up might might be a better design????

My JD F725 radiator is horizontally mounted above the engine with the hydraulic cooler on top. There is a screen on top of the radiator that is easy to remove and slap against the wheel to free the clippings.

In the end a closely monitored engine thermometer should alert me to heat problems.

Hmmm.... horizontally mounting a radiator designed for vertical mounting... hmmm... If I can fill it I don't see why it wouldn't work... hmmm... any comments?