My first 6x6 Max IV project

[phabib]

What do people think of 18HP Vanguard to power this thing? I found one for $300. I also found a 25HP Kohler, but its $675 and the clutch would cost me more too. Will the 18 get me where I'm going, or should I just keep waiting for a 20 or more that I can afford to come along?

I need to post some pictures here. I have everything off the frame and sandblasted clean. The frame will get sandblasted next. I'm going to powder coat everything before I start to put it back together.

[amphibious drew]

I was using a 16 with a red spring in the driven clutch, and it went well even loaded down. Sometimes I had to work the engine a bit, but the 18 for that price is a steal. Grab it, put a red spring in the clutch, and drive it. If you find a deal on a bigger engine, you will be able to get your money back no problem.

[phabib]

I missed out on that 18HP. After seeing it listed for a week, I called about an hour after the guy who wound up getting it. Oh well, there will be others now that I know I can set the lower limit at 18 instead of the 20 I was holding out for.

On another topic, I'm thinking of replacing the band brakes with discs. Since I'm making tubes and sprocket assemblies anyway, I figure stopping is at least as important as going. I'm looking at the 6 3/8 disc and the heavy duty caliper listed on this page. Brake Disc Components for Go Karts & Mini Bikes | Go Kart & Mini Bike Parts | MFG Supply Has anyone here done this, or maybe want to talk me out of it?

[phabib]

Things have gotten as apart as they can so I'm starting to put them back together. I sandblasted everything other than the frame in a cabinet blaster I have access to. I just picked up the frame from having it sandblasted. The T-20 stiffening kit is due to arrive on Tuesday from RI, bearings ought to show up at about the same time. UPS dropped 42 pounds of new sprockets on my porch last week. I'm about to order discs and calipers to replace the band brakes when I make the new tubes/sprockets.

I am ready to start powdercoating everything in a silver/black vein pattern. Its got a bit more silver than I would have liked, but solid black just looked boring.

I'll get some bar stock and DOM tubing for the axles and tubes.

Once that's done, I'll clear out the old projects off the workbench and open the T-20 for a look.

BTW, I got my bearings from "The big bearing store" The 62 mm triple lip outer bearings were $11.25 each, the inners were $9. After a bit of poking around that was the best I was able to come up with. I was still looking at about $135 with shipping.

[phabib]

How does a 20HP opposed Kohler sound? The seller says it came out of a Bobcat and that it runs fine. Comes with a clutch. Asking is $400.

[phabib]

Any opinions on that Kohler? Its the Magnum engine, which I think is the heavier industrial one. Complete and running with a clutch sounds like a good deal for the price, but I don't want to get it if its really the wrong thing.

Thanks.

[jpswift1]

The Kohler opposed twin Magnums were factory Recreatives engines at one time. They are pretty tough engines, but I personally would hold out for a newer V-twin Briggs or Kohler. For $100-$200 more you could find a nice used Briggs Vanguard.

[phabib]

Thank you for all of the help you've been providing answering my questions.

This is the rare answer where I won't be taking your advice. The seller agreed to $300 for the engine and clutch so that seemed like too good a deal to pass up. If for some reason it doesn't work out, I think I should be able to at least get my money back on the Kohler if going to the Vanguard seems like the thing to do. I now have all of the parts I need to put it back together. Its all about time to work on it now.

[phabib]

It goes a lot slower than I would have liked, but I am making progress. I've been lucky to get a couple of hours a week to work on it and since I'm making 6 new axles and hubs and 6 new sets of sprocket/tube assemblies that's a bit of time too.

I have the frame re-enforcements welded in place and the 6 axles drilled and the bare tubes fitted to each one. I have the left rear axle and tube made with the sprockets welded on and (surprise!) it lines up under the T-20 output sprocket as if it belongs there. Next I'll make the center one, and keep working my way forward on one side before going to the other.

For the front, I have some disc brakes that I'm going to attach to the axle. I made new hubs on a CNC machine, but they're not quite right. It turned out that the carbide end mills I bought on Ebay were not quite .250". I'm guessing they had been re-sharpened and so were smaller. As a result all of the holes are too small. I bought a new end mill from a reputable tool store and I'm going to make a new set. Since I had to buy metal anyway, I'm going with 3/8" thick for the hubs. I'm also starting to keep an eye out on Ebay for good deals on quality O-ring chain. So far I picked up a new Tsubaki chain to get started.

Once I have the mounting hardware in place for the brake caliper and the brake pedal attachment figured out I'll powder coat the frame.

I'm still going to need to open up the T-20. All of the plungers are stuck and I may as well look at the brake bands given all the other stuff I'm doing.

[Noel Woods]

While you have the t20 apart, I would switch out the output to 13 or 11 teeth, It will slow the machine, but the gearing will dramatically improve the off road performance. These things are not built for speed anyway, and I think with 20hp the top speed with 13 teeth would be around 20mph, with 11 teeth, maybe 18mph.
A low geared Max4 is hard to beat in the mud.
I like the other things you mentioned on the build, keep up the good work.

[Adondo]

...These things are not built for speed anyway...

I'd second the motion about lower gearing. My Max II does 28 MPH according to the GPS, and that's INSANE in a skid steer vehicle. I doubt I'll ever do it again after that "let's see what she'll do" test. Anything over 20 MPH, and it's all to easy to get out of control using a set of steering levers. If it gets somewhat off being dead straight at speed, it's not that easy to correct without see-sawing. Surviving a flip at 28 MPH would be a crap shoot.

On edit:
The two times I've been out in the desert playing in sand, (After getting the GPS installed) following old roads etc. my average speed is 8 to 10 MPH. Going back to my truck that might be 15 miles away after a good run, I still only do about 12 ~ 15 MPH. If you want speed, buy a Polaris RZR.

[BREEZE]

Who has the different size sprockets for theT-20???

[amphibious drew]

Who has the different size sprockets for theT-20???

Forum member whipper can make you up a set. He and his wife Bridget are great people and a huge asset to the hobby.

[phabib]

Thanks for the advice. I hadn't thought of changing the T-20 sprockets. Last year just for the experience of it I made a chain sprocket and found out how hard it is to make a good one. I was using Inventor to draw the part and got the point where I couldn't get the formulas from the handbook to work so I went to a much simpler description which didn't have all of the curves and clearances in it that the official one did. I'm sure that sprocket would have beaten itself or the chain up much faster had I tried to use it.

Thanks for the pointer to whipper, I'll get in touch if I don't run of money by that point.

[Tomo]

Hi
CVT clutch systems work as a pair eg 700 series comet 780 drive 770,780,790 driven
Also u need the correct belt to match clutch width , and the center to center distance of the shafts .
If in dought call Quality drive systems for supply of correct clutches and belt .

tomo