My Mini Mud Motor build so far

Mark W

Mark W

Well-known member
I caught the bug when I saw the postings about the min mud motor and after much discussion between Ed L, Tom Scholberg, Mark Cheney, "Ripped Off's" plans from another forum, John O'Neal, and others, I had to try to build one just for the fun of it. Will it work, who knows. It did give me something to do these past few weeks and I met some great people along the way. Here are some pictures of the motor. All that is left is to connect the prop when it arrives, machining the 3/8" drive shaft to fit into the weed whacker motor, hook up the throttle, attach the tiller, and put on the motor mount. Nothing too hard.

Here is a picture of Tom helping me out in his shop at school. Good thing I was there to help him out or this motor shaft would not have been finished.

Tom3.jpg

Here is a shot of the motor after the shaft has been coated with a 3M Rubberized undercoating product. this should hold up well as it is used to paint the wheel wells of cars.

Mudmotor1.jpg



Hope it works out. Sorry about the picture quality, you can't get good photo's on the cell phone.

Mark W
 
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Mark

Looks like a professional model, the motor that is not Tom :)

I think a lot of people are interested in the performance and design. Looks like you got the right folks involved to get the project completed.
 
Mark,

Looking good! Man you've made progress this week. Did you attach the seals like we talked about? How'd that work?

I have the weedwacker, bushings, seals, tubing for the handle and prop. I haven't ordered my shaft tubing and shaft material yet! I have the order sheet in hand but as I was ready to place my order, it seems the company I work for is apparently having year end cash flow problems. I could really go on a rant but ya'all don't want to hear that.

What product did you use on the shaft tube. Is it a spray? Looks to smooth to be a bed liner roll-on product.

Keep the pictures coming.

Ed L.
 
Mark, Thanks for posting the picture, my wife thought I was goofing off then but the picture shows the seriuos nature of our work. BTW thanks for all the help on maching the drive shaft, I would not have ever finished by myself. I have to admit the wheels are turning in my head now. How do they get that Harley motor mounted??? Maybe a 1000 cc would help. The coating looks like a winner. Can't wait to see some one skiing behind the Hoofgren. She does look good.
 
I had to go and buy a different drive tube as the first one I got was not straight. The second time around I took my time and found one that was the exact ID as was needed (3/4"). The seals fit tight into this new tube with Tom's nifty seal driver (round hollow tube) They are in there good and tight. At the bottom I added a 1" OD washer with a slightly bigger than 3/8" hole to put the drivehsaft through.

We (I watched Tom do this) had to put the bushings on the lathe and file off some to make it go into the tube. With the exception of the middle bushing (it slid in easily), these were also press fit and then a set screw was tapped into each of the bushings to hold them in place just in case.

The "paint" is 3M's Underseal Rubberized Undercoating (part #8883). It is used to coat wheel wells in automobiles and is sold to any body shop in town through distributors. I bet you could find something similar at any of the auto chains. I figure that if this coating can withstand the environment a wheel well sees, it should work well on the driveshaft. It is not a smooth coating but I like the looks and the performance should be great.

I'll take some higher res pictures later and send them your way Ed.

Tom and I had a good time yesterday. His shop is like a candy store for big kids. You name a motorized toy and at least one of them was in his shop either assembled or in pieces in boxes. I had to teach Tom a few things to complete the driveshaft. Yeah right!!!

Mark w
Mark,

Did you attach the seals like we talked about? How'd that work?

What product did you use on the shaft tube. Is it a spray? Looks to smooth to be a bed liner roll-on product.

Keep the pictures coming.

Ed L.
Click to expand...
 
Mark,
Had a thought this AM, when you pump grease into the tube the air has to go somewhere. Maybe take out one of the zerks or even better a set screw until grease comes out. Hind sight being what it is maybe the zerks should have been in the bushings (that is where you need the grease). I am also thinnking more about 80/90- gear oil. But we will probably have more "testing" to do this summer. "One day closer to open water". Maybe you should have ordered more props? Always thinking. Maybe I can find a BIG motor.
 
Tom,

I have 80/90 gear lube I am going to use rather than grease but then I thought what about outboard lower unit oil. What is the difference in lubes?

Ed L.
 
Not much Ed. The 80/90 gear lube isn't as clean as lower unit oil. I'd get synthetic....it's about the same price as regular. Are you going to fill the tube on all sides of the bearings? Mark, that is one sweet motor system you have going there. Like Eric said, it looks like a factory model.
 
Lee,

That's the plan. I want to limit the amount of drilling and tapping with the hopes of eliminating exit points for my gear oil. My thought was to install the three bushings and seals at the prop end and start the driveshaft from the prop end then fill the tube with oil prior to fully assembling the driveshaft and motor end seal. I'll also use a shaft collar with set screw to eleminate the possibilty of the driveshaft coming out of the tubing if the driveshaft comes loose from the motor.

Ed L.
 
youze guyz are krazie lol, I just got in some BIG INDUSTRTIAL COMMERCIAL weed eaters btw ED :)

29CC by SOLO made in germany keep the SAW blade and the prop mounted now there you got
sumthin.

? Why wouldnt you want to use Grease in them like the go-Devil? not runny and would stay in there. On the Older GD you would losen the top nut - grease then retighten by hand was all. The new ones have the grease cups
that let the air out.

Looks like a cool project keep up the good work!
 
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Mark, Ed and others,

My small Mud buddy uses oil. On the small motors, oil will rob you of less horsepower than the grease will. I think one would be surprised just how much resitance the grease will add to turning the shaft when the tube is packed full. Now greasing just the bushings is a different deal, but then you must have a way of keeping the grease in the bearings only.
 
Dave,

Hey, a guy has to do something in the off season. Sorry bud you're just a little late. I already have the motor. Did you have a chance to see if you can get the 1" O.D. x .125 wall aluminum tubing?

The reason I'm using oil rather than grease is because these little engines will loose to much torque over coming the thick grease. I'd rather use sealed needle or ball bearings and no grease or oil but I couldn't locate bearings in the size needed.

Ed L.
 
Huntindave,

That's the reason I decided to use oil. I am surprised your motor uses oil though. Does yours have a pop valve to relieve the pressure build up in the shaft tube or is that only used on motors with grease?

Ed
 
Ed try sintered bronze bearings they will stay lubricated better using oil. I think you can get them from McMaster. I use some in some of my designs in air tools. Mine are made for us, I'll check tomorrow where we're purchasing them from and let you know.
 
Gentlemen:

Yes you can get 1" x .125 wall dom aluminum tubing. All kinds of wall thicknesses are available. I grease my cast bronz bushings with synthetic grease and fill the voids in the tubing with synthetic 90 weight. Pump it in the bottom untill it comes out the top and leave an opening to the atmosphere open to keep the internal pressure equalized with atmospheric pressue so that there is never a vacum inside to draw in water past the seals. It is the grease that becomes the bearing between the bushuing and the shaft. Use a bronz bushing and a stainless shaft. It is very difficult to keep moisture out of the system. That is why hard carbon steel bearings go out. The carbon steel always corrods and then grinds itself to pieces. Have fun in the process gentlemen. It is all in the journey.

Mark
 
Sintered bronz are designed to run on 30 weight oil and will not take as much pressure as greased or gear oil in cast bronz. Lubricant heavier than 30 weight oil clogs up sintered bearings, makeing them like cast bronz without the pressure bearing capacity.

Mark
 
Mark your right I didnt read the post carefully enough, gear oil would clog sintered bearings. It would work but not as well as cast bronze under pressure. I use o-rings between the pressurized side of the tool and the sintered bearings. We use air tool oil which is much lighter to lubricate the sintered bearings and the o-rings.
 
Hi Mike,

That's what Mark and I are using. Mark sent me the manufactures name. I've got everything but the s.s. driveshaft and tubing.

Ed
 
Mark,

What we're using is cast bronze impregnated with teflon. These should work pretty good for a low tech toys. If the oil tube seals don't work I'll probably order well pump leathers to insert as an upper and lower grease cup. Then I'll drill and tap a zerk and fill with grease only around the bushings leaving the bulk of the tube empty.

Mark W. tells me you're working on one also and about to put up some pictures and info. I've been checking your site but haven't seen anything yet. How's your project going?

Ed L.
 
My project is often the victim of a list of hony do's. I have every thing in hand but the large aluminum J belt aluminum micro groove driven pully. I have a steel one for trying now as that was available commercially. I am haveing an aluminum one cut currently from some one who can make them repetitively if it works out. All of the cad, laser cutting, and CNC break work is now in hand. I hope to get the drive tub assembled today, monday.

Mark
 
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