DrFrunkenstein

Hi everyone. I have two 31cc weed wacker motors that I have lying around, and wanted to build myself a truck around that. I have a T-Maxx, and hate that the engines are never reliable and it seems it's always down. So I'm building something that will hold up to it. I was thinking of a custom chassis (laying it out as I type), 4wd if it's possible, 2wd if not; monster truck, possibly a desert racer (like the pre-runners and such) Maybe I'll make both, _IF_ I can get my driveline and and suspension straightened around. I need to know how to: Actually get the power to the wheels, IE: I need chains, maybe an axle instead of the chains, a differential, maybe a transfer case if I make it 4wd, and suspension arms... shock towers are no big deal for me, make a cage that has mounts on it. so... what I want to know is if anyone knows where I can get axles/axle material and where I can get a drawing or manual of one of these to see how they are layed out.

DrFrunkenstein

Sorry if this is such an odd question that no-one can answer it... but I think I got it figured out. I'm going to make it 2wd since I don't have or know where to get a transfer case. I'm going to use (almost positive) a self propelled lawn mowers differential to power the truck. I have a couple ideas for front A-Arms, I think I'm going to do a quad style setup, A-Arms up front and swingarm in the rear. I'm going to make my own shocks (out of PVC pipe ), the front arms will be really simple, and so will the swing arm. I was thinking of making it two, possible three speeds, no reverse, but two or three speeds. uhm.... if anyone has any knowledge on where to get this stuff, please, please post back here, thanks.

Isphius

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goto mfgsupply.com they have some good gokart and atv stuff. those self propleled things arent diffs its just an axle. You can get shocks from a full suspension mountain bike. cut the front fork up, and the rear can be for the swing arm. If you get the mounting positions right the rear should have like 8 inches of travel and the front will have more.

Isphius

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I am also building something similar to your truck, but with a 2hp briggs and stratton from a minibike my neighbor gave me. This motor revs alot higher than a standard lawn mower engone so i think it should be pretty fast. i dont know what im going to use for stering though.

DrFrunkenstein

Thanks alot for the replies! That sounds like such an awesome idea about the mountain bike shocks, great idea! The self propelled lawn mower (mine at least) is a differential, it's locked though, but that's great! (just off-roading here) My weed wacker motos are rated at.... 2.5-3 hp, and I'm gonna try to port one of them. it should scream. Thanks again for the replies, keep em coming!

JohnVH

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You guys gotta show pics of progress!

DrFrunkenstein

The only progress I have made so far is: Make a dual exhaust system for the motors, gain some information, and get both engines running. The next thing I do is get my diff(s). As soon as I get that I can make a chassis template, then make the actual thing.... We're really low on money this month (putting Christmas off... tell you anything? ) so I won't be able to get any parts or supplies for quite some time.... but everything I need to buy will be put on my list. My dad borrowed 90 bucks from me, so I have that much to throw around also. I'm hoping I can find one good bicycle and scavange all the parts I need from that.

And... I thought I'd let y'all know how my two/maybe three speed would work Basically, get a mountain bike with multiple speeds, and keep the derailure in the whole loop, and get a T-Maxx radio system, and use the 3rd channel to pull/push on the derailure cable If anyone has any other suggestions or websites where I can go to look for junked parts or cheap parts, lemme know please.

Isphius

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I have my truck all designed, i just need to get some stuff for it. for diffs i am using two bicycle freewheel wheel sprockets to make a diff. this way the outside tire can spin faster, but they cant spin slower and this makes it pretty much a locker. The bad part is you need 2 spererarte breaks on eack axle beceause of the oneway action. i also have a pretty cool front suspension worked out. ill post my drawings if i can get my scanner to work. i originally designed it for a gokart but it could be used if less powerfull springs were used

DrFrunkenstein

that makes me think, if you need two seperate brakes, that also means you need two seperate drive lines/drive chains.... You have a good idea, sounds like it would work better for possibly front wheels or free-wheeling. I'll draw up a quick sketch of my whole trucks design and take a couple pictures and post em up here. I love that you don't have to use a host on these forums! talk to y'all in just a bit

MatJam

Take a look around for schematics of the Traxxas 1/6 Monster Buggy. It uses a Zenoah 23cc (heli?) engine. It may give you some ideas on how to set some things up.

Site:
http://www.traxxas.com/products/nitr...rx_monster.htm

Parts:
http://www.traxxas.com/products/prod...ster_buggy.pdf

Exploded view:
http://www.traxxas.com/products/nitr...ster_views.htm

Self-propelled mower diffs may not be up to the speed that you'd be getting from you're machine.
I'm guessing their from an L-Head mower engine, which probably put most of its power into spinning the blade. And what would be its redline, 4000, maybe 5000 rpm at most.
The two strokers you've got would definitely go a lot faster than that.

If you are trying to get away from using diffs, here's an idea completely off the wall: use slipper clutches on each wheel shaft. In theory, the clutch will allow the inside wheel to slip a little bit on a turn. It would not make the outside wheel go faster.
Should be fairly cheap to make, just two plates sprung together and an element between them.
If you want to go that route, you could even devise some way that as the steering turns one direction, it eases the slipper on the same side. That'd be pretty complicated and all theoretical though.

For a transmission/drivetrain, see what your local junkyards have in the line of old snowmobiles. ATV, dirtbikes and other stuff might work as well. Some old fat-cat or mini ATV tires would be awesome on a Monster Truck!

DrFrunkenstein

man, you're a genious, I didn't even think of looking at Traxxas Buggy, that's perfect! And that slipper clutch thing, I get exactley what you are saying, and it sounds, if they were tightened correctly, like it would work greatly. These are my plans so far.... drew it up last night, a bit off, sorry =/

DrFrunkenstein

sorry about that, this was sposed to be with my last post.... here goes.

Isphius

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The slipper cluth thing would work, but what if they got wet? and also a dirtbike trans would work, but you would need a monster servo. Is it possible to use a servos electronics with a 1/2 hp electric motor that i have for steering? and you also dont need two seperate drive chains with the freewheels, you just weld a sprocket to the outside of them. you need brakes somwhere on the axle though because it will just stop the chain and let the axle spin if put the brakes before the axle. if you have some money you could also get ratcheting hubs from a racing kart. They only lock to wheel under power, but they spin free when coasting, but there about 100$ a piece.

drevil

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UPDATES?????????????????

XR2PROBE

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HEY GUYS YOU ALL SHOULD CHECK OUT ....NEW ERA

THEY HAVE A FEW 1/4 AND 1/5 TH SCALE TRUCKS...........ALSO THEY HAVE A GREAT TECH DEPARTMENT AND IM SURE THEY WOULD BE INVALUABLE TO THE SCRATCH BUILDER ALSO ANOTHER LINK TO CHECK OUT IS....................HARM

DrFrunkenstein

This is an update for the "large RC project" I started to draw up pictures for. Uh.. tight on funds, I had these pieces lying around, thought I'd throw it all together and see what I came out with. I need a more permenant motor mount, and probably a new deck (This one's completely thrashed), but it seems to work OK. The motor won't start unless I use starter fluid, so no tests have been run. I'm hoping to use some of my RC gas (Nitro) tomorrow to see if I can't get it to stay running... keep your fingers crossed

Grr... tried to post the dern picture, always come's back as "too big" (I've always heard the opposite.. )

ejweelin92

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get a good and cheap clutch from a used chainsaw. also futaba makes a nice land use only 4ch radio, more options!!

DrFrunkenstein

Ok, another update. I've gone a COMPLETELY different route. I threw the engine on a Dirt Board (Skateboard with large, off-road tires). The engine I'm using already had a clutch system with it, woohoo! I've used the chains and sprockets from the main pulley assembly of a Snow Mobile (the chain and sprockets are about the size of those you would find on a quad). I've got it mounted to the deck with two L brackets, and one large U bracket at the rear (mounted by one of the muffler bolts). I've got two, what used to be L brackets, now bent into a kind of... twisted, elongated L brackets to hold the gas tank. I'm hoping I can give it a test tomorrow, spent all day today trying to get the bugs out and the such.. looks pretty sweet

I did a test today with a screw gun. I put it against the clutch bell, stood on it, and pegged it. It lit up the chain and sprockets!.. but didn't turn the wheels at all. The rim was spinning, not the tire I had some extra Tire Glue (PERFECT!) lying around, so I glued up the tire, and put 4 dry wall screws in it. Hopefully that'll hold it...

Now the hard part... getting the engine running, and keeping it running for longer than 2 seconds... It usually stalls out. Oh well, if I can't keep it going, and don't figure out what is wrong, I'll just take it to a small engine repair guy, and let him get it running, and play with it

XR2PROBE

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Hey DOC here's a few tips that might get you going for a succesful run

1 change the plug
2 remove the electronic timing unit.its the piece that is made up several thin plates of metal and is attached to the plug wire( but remember which direction it was in uppon removal................next lightly sand the two indexed prongs on the magneto.the unit you just removed..the area that would come close'est to the fly wheel
.......next lightly sand the two magnets in the fly wheel...and for all above mentioned use #600 grit sandpaper or finer and once all rust is removed use 800 to 1000 grit to polish both surfaces .......both on the magneto and the flywheel
then upon reassembling the unit use clear transparency sheeting (just a thin stripp is all you will need about 3"x 1") and sandwich it between the fly wheel and the magneto then tighten your bolts and remove the strip
next ....if you choose to do this next part please contact me via e-mail and ill walk you through the steps needed

for the above mentioned i am refering to the carbeurator

if not send it to a proffesional shop

XR2PROBE

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Just for your information i also run weedeater and larger r/c boats

XR2PROBE

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ok heres my problem .....I HAVE PICS ID LIKE TO POST TO THIS FORUM BUT IM UNABLE TO CAN I SEND THEM TO SOMEONE HERE AND THEN PUT THEM INTO THIS FORUM FOR ME

Isphius

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so is it a skaeteboard or a big rc truck now? i have had a weedeater powered skateboard since last summer if you needed help with that i could have helped

Dias-RCU

Has anyone thought about putting a weed eater engine in a Power Wheels? I have a Power Wheels Bigfoot with a radio installed. It runs great as long as I'm not trying to go uphill. They were designed to use the weight of the kid to keep the rear wheels planted so it spins anytime I try to go uphill or play in grass. I'm planning on cutting an old inner tube & using it to cover the back wheels & maybe moving the batteries to the back for added weight. Maybe I'll throw in the radio from my full size truck along with a pair of speakers. It couldn't hurt. lol

DrFrunkenstein

Ok, first off, the engine runs, WHEN we use starter fluid, and it won't last very long if we keep using that
The plug is still good (bright blue spark[yes we tested it]). I haven't though of taking the rust off the magnets/magneto, sounds like a good thing to do even if it isn't the cause And for the third suggestion, going into the carb...: I already have, we tore it down as far as we wanted to go comfortably. We didn't mess with the needles, and they are still set to Californian weather (I live in Michigan now... big difference). If you wouldn't mind though, XR2PROBE, I would love it if you walked me through it . Also, as for your picture dilema, scroll down past the actual posting board (the thing you write on, grr, brain fart, sorry) and look for a thing named "Attack file:" Click on the "Browse" button next to that, and look for the picture you want to post. Click on the file name of the picture, and you should be ready to go. Just click post, and it should work.

Isphius: I would love it if you could give me any help in this area. And it's a skateboard now, might turn into a large RC at a later date... but Skateboard is what I could do when I had the urge to build...

Dias: I have often thought of mounting electronics in a Power Wheel, or a go kart, or something like that that isn't too overly-powerful (so it wouldn't get away from you too fast ). But I agree, it would need better grip. Maybe some go kart tires/wheels? Or small trailer wheels? They are heavy, and would provide more grip than that hard plastic

nitroman88

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you need to strip down that engine. Clean everything, and put it back together. I had a buddy that had a engine similair to yours that would run on starter fluid then stop. he took it apart and cleaned everything and fired it up and it ran like a dream.