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  #1  
Old 06-18-2006, 01:25 AM
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Building a RC with a weed eater engine, please help me with the design and mounting!!

I just acquired an "eager beaver" 282 weed trimmer made by mcculloch for the primary purpose of using the engine in my own custom RC truck.

first question is...weed eater engines can be used...right? the mounting will be a little weird, but other than that the basic concept seems compareable to that of a conventional glow engine....

Basically i'm open to ideas and I need help coming up with a good way to harness the power.... and then i will proceed to designing the chassis around the proper drivetrain....if indeed this engine is practical.

some things i need to know are...

what kind of clutch do i use, i dont know what the stock one is like since i havent removed it yet...i'm thinking i have to buy a new one or at least a clutch bell with a sproket that will run a chain drive...

how do i mount the engine...all I see for mounting are the bolts that mount the crankshaft-side of the engine to the arm of the weed eater, so i'm guessing an odd mounting setup is going to be needed..a mount that will portrude up from the chassis alongside the engine as opposed to under it like a glow engine.

I can probably work out details such as the throttle and most of the chassis design, its all ready to attach a servo and crank the throttle. but right now i'm at a blank slate here and i need tips...I'm hoping for people that have already made rc's with an engine out of a garden tool to post what they've done...

For those that have used 2 stroke gas RC engines such as those by zenoah...you could give me tips too... except on mounting?

I'm hoping to stay on the cheaper side of things here...which means i'm not buying a zenoah engine OR a chassis...I AM using the engine I found unless i find another one that is cheap and better. I found this sucker for 3 dollars. I might buy prefabbed parts, such as minor suspension components, but only if I cannot make the equivilant on my own. i dont want to shell out big bucks and i want it to be my own... i can do it but not without some help on what to do first....

I have a t-maxx, and i'm pretty good at designing things. I've been in the hobby for a while now, so I believe i can do this and for those skeptical I'm not some little kid that got a hold of his dad's old weed eater. I intend to actually do it, but not without some help... I can design basics but the complicated stuff relating to the non-RC engine is a new thing to me and i dont care to screw it up.

lastly, please dont say anything to the effect of me never starting or finishing this project, it may take a while but i've always wanted to do it and negative comments are just pointless in this thread because thats not what i made it for. If you dont think i can do it, please by all means keep it to yourself; thanks

with that said.... thanks for looking and reading all this! I cant wait to get started...if this engine will work.
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Old 06-18-2006, 01:48 AM
Giant655 Giant655 is offline
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You are actually in luck. The HPI Baja 5B ( their new 5th scale buggy) has a big 22cc engine that already has a good clutch design. Check out parts listings for that at www.hpiracing.com and you may luck out!
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Old 06-18-2006, 02:01 AM
associatedude92 associatedude92 is offline
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what scale is it gonna be??? cause that would make a big difference!!!
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Old 06-18-2006, 02:25 AM
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it doesnt matter, i wont go bigger than 1/5 because i believe that would be all my little engine could handle, but if someone proves me wrong....i'll consider larger.

right now I'm thinking a 1/8th scale-ish truck or buggy-like thing... i could go smaller but things would start getting really tricky and i dont want a crazy power-weight ratio or a truck so short it will only pop wheelies...

so 1/8th is about the size i'm going for...if i could use monster truck meats that would be great.

I'll post pics of my engine soon and tomorrow i'll pull the clutch to see what i can buy in terms of pre-fab drivetrain parts. hopefully i can steal some parts from the HPI!!

thanks giant!
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Old 06-18-2006, 03:16 AM
highroller highroller is offline
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There are several companies building 1/4 and 1/5 rc cars, using modified weed eater motors. You could do a search from some of the manufacturers, look at the arrangement they use in mounting engine. Many are modeled after the smaller scale of RC cars, dragsters (Pro Stock, TF Funny Car and Dragsters),Stock car, Outlaw, Sprint, Touring Cars and Monster Trucks.
Try the quarter scale sanctioning body QSAC (www.qsac.org) for links to manufacturers and possible info.

Last edited by highroller; 06-18-2006 at 03:27 AM.
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Old 06-18-2006, 04:44 PM
teampeter teampeter is offline
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How about a 1/8 scale, tube chassis, dirt/sand rail type thing. That way you could actually mount the engine on the side of the chassis.

Pete
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Old 06-18-2006, 05:08 PM
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highroller- thanks for the link, i'll be looking through that for good pics..

teampeter - i never thought of a sand rail type thing... that sounds cool. I also like the mounting idea...i'm assuming that you are thinking of mounting the engine to what would be the rollcage on a full size sand rail?

either way it sounds good... I'm looking at pics of the sprint cars and they have a belt drive, but this is looking better because there must be good cluthes out there. so i can probably get one. i'm going to go outside and see what i have.

does anyone know what those sprinters are made of? they have tube chassis' and it kinda looks like aluminum... could i use steel tubing from a hardware store? We have an arc and Oxy. welder so hopefully i have the tools to assemble whatever i come up with. if not maybe i could bolt it together? i guess thats all for later though...oh well.

ok so so far what i have for ideas;
sand rail/dune buggy - 2wd
monster truck - 4wd if i could somehow get the power to the front too
stadium truck - 2/4wd

i'll post more on drivetrain stuff later...i have some ideas for 4wd but dont know if it will work. i need to sort out the engine first.
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Old 06-19-2006, 10:23 AM
mbbaj2001 mbbaj2001 is offline
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THe expert is in the house!!!!!!!!!!!!!
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Old 06-19-2006, 12:44 PM
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awsome!! how big is the engine in the tube chassis in the front? i have a 5hp gocart that is really small i could use....lol... j/k. but anyway...seeing this makes me want to invest in a chainsaw engine....out of a BIG chainsaw...lol
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Old 06-19-2006, 12:54 PM
mbbaj2001 mbbaj2001 is offline
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A 4 hp Zenoah G260 red cap motor. The big truck has a 3 hp G230 Zenoah motor and 4 wheel drive with 4 wheel steering.
Both truck have a reverse transmission.
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Old 06-19-2006, 03:07 PM
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i jut got a chainsaw engine, and i was going to make this thread, but you got here first. and i was designing a buggy, but i didnt know what material to use(aluminum?) but, what wuld i use for the transmission, i was think something along the lines of a savage transmission, butidont know if it could handel the power, or if i would have to make it mteal gears, with Steel CVD's, or maby a small chain form a bike, or and electric scooter. ill finish reading threw thins, and i might answer my questions
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Old 06-19-2006, 06:05 PM
jebus your fate jebus your fate is offline
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makes me want to build one too :P as a school project
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Old 06-19-2006, 06:54 PM
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Quote:
Originally Posted by mbbaj2001
THe expert is in the house!!!!!!!!!!!!!

Hey, do you have more pics of the truck on the front left?, that thinng is AWSOME
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Old 06-19-2006, 09:02 PM
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Quote:
Originally Posted by Out Of Control
i jut got a chainsaw engine, and i was going to make this thread, but you got here first. and i was designing a buggy, but i didnt know what material to use(aluminum?) but, what wuld i use for the transmission, i was think something along the lines of a savage transmission, butidont know if it could handel the power, or if i would have to make it mteal gears, with Steel CVD's, or maby a small chain form a bike, or and electric scooter. ill finish reading threw thins, and i might answer my questions
why use a transmission? dont you have a clutch on that thing with a sproket? i would think you could just take that and run a chain drive to the rear axle and do a simple trailing arm setup. I dont know what i want to do yet...i was thinking of just that but...not that you mention it...

I would use any tranny out of a dual engine-capable truck, or somehow rig up the clutch on the chainsaw engine to mesh correctly with the spur attached to a 1/8th scale ALL-METAL differential or center spool which would then move to the rear/front just as in a 1/8th.

what do the people that HAVE done this think? i think more than one person here needs help with this. gear ratios are also going to be an issue. i'm going to go snap some pics of my motor.

Quote:
Originally Posted by mbbaj2001
A 4 hp Zenoah G260 red cap motor. The big truck has a 3 hp G230 Zenoah motor and 4 wheel drive with 4 wheel steering.
Both truck have a reverse transmission.
can you please give more info on the transmissions and other aspects that you might think are vital to our designs? i'm interested mainly in the drivetrain design and what components were used in your truck. power handling, like mentioned...is a bit of a concern compared to a 1/8th or smaller...
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Old 06-19-2006, 10:43 PM
SoonToBeLowS10 SoonToBeLowS10 is offline
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As for the weedeater, I dont believe there's a clutch. Atleast in the one i pulled apart. It's Direct Drive, And the engine was mounted to a shaft.

Im not too sure on RC clutches, But i know ADARacing.com make's one for Go-ped's / Zenoah engine's.

If these small motor's can pull a Go-ped and 130ish lb rider to 30ishmph, I doubt it'll have trouble getting a frame up to those speed's.

As for a better engine for cheap, Im not saying TO do it, But it'd probably help with mounting issues / Clutches. GopedNation.com is a great place to buy part's for engine's from. I've seen zenoah 230rc's going for $50-60, And 260's for a tad more. Plus there's stroker crank's, big bore kit's, pipe's, carb's, Ect made specifically for Zenoah's.

But back onto the weedeater motor. You'll probably have to do something about the Flywheel, As most from weedeaters are on the crankshaft side, And would get no Air to the engine when the clutch / tranny's mounted up. The pull start was also probably built into the weedeater housing, So you'll need to do something about that.

What do you plan on doing for break's on this rocket, if you dont mind me asking?
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Old 06-19-2006, 11:55 PM
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well right now i didnt think of that...but once i figure out how to rig the drivetrain i'll probably just have several disk brakes from a 1/8th sized RC mounted on a shaft somewhere after the clutch, if i use a chain that will be on the rear axle - likely to be solid to save money since i'm planning on an offroad beast. i'm not so sure what i could do with the radio part though... hopefully i could rig it so the throttle AND brake are operated by a good servo; i really dont want to get into programming two servos to run on the same channel but run different end points...if that's even possible. I could also remotly move the throttle via the stock throttle cable that's attached to the weedeater's go button if i cannot get linkages to reach the throttle and the brakes.

And as you just mentioned, I sadly discovered the hard way that there is no clutch in my weedeater, probably since it's a smaller urban use type, not the kind you would want for a lawn service company CONSTANTLY using it. i recieved it in nice looking condition but the cable in the shaft has something broken at the other end.. since it seems like a lighter duty whacker it probably just doesnt need a clutch....crap!

Below are some pictures of what i have.

The good:

- the cylinder head looks to be bolted on from the bottom, so I could remove the bolts, get longer ones with the same threads, and thread them through a custom engine mount and THEN into the engine to hold it together and mount it all in one smooth move. only problem with that is i will have to loosen the head bolts if i ever need the mounts taken off the block. oh well... it's still probably the best way. i might need to get those machined out of aluminum.

- the front mount that bolts to the plastic housing can most likely be removed and still leave the engine operational, i think its just an add-on to the basic motor to make it weed-eater compatible; no seals or anything hopefully. so once removed this will be a much larger displacement but not extremely larger than a normal nitro engine... at least its kinda easy to handle.

- The motor runs pretty well and starts great. if i can get a clutch we're in buisness.

the bad:

- like soontobelow mentioned on his weedeater, mine has only a flywheel, which also as he mentioned will probably not efficiently get air to the engine, requiring some sort of extra assurance of getting the engine cooled.

- the rear crankcase cover on this little bugger is composite, not terrible but i't has portrusions to hold the gass tank and i will have to trim it later on... minor annoyance...and i just dont like seeing plastic on such a part. i dont know exaclty how these are built.. if i take off that cover will i see the rod and main shaft? is it just a barrier for dirt or does it hold anything internal in place?

- BIG ISSUE is the starting of this once it's in my RC. I dont know how to get around this because the engines pullstarter was designed around using a the flywheel on the output side and its not going to be easy getting this to work

- stupid recol spring decided to spin part of the spring inside the holder and i'm going to have to fix it... scary because i HATE recoil setups and they always seem like they will pop out and cut me or slash my face. i need to basically get a new recoil spring because this one is getting messed up.

I'm probably going to remove the flywheel later to see what the shaft and output look like, and see if i can find a fan or thinner flywheel to more efficiently move air past the engine and allow more shaft room. right now the fins stick out over the threads and the flywheel has two ratchets to allow for the starter.







The only other thing i can think of to solve the clutch problem is to use that ouput shaft just the way it is, and stick a square shaft into it that will then allow for mounting of a clutch of any size, then from there i can run a shaft or chain. As it sits there arent enough threads to attach a clutch unless i somehow bolt on some sort of extension in place of the bolt holding on the current flywheel.
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Old 06-20-2006, 10:26 AM
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i would take the gas tank off, an move it to a diff position later, to take up lesss room
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Old 06-20-2006, 10:32 AM
mbbaj2001 mbbaj2001 is offline
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That motor is best used for AIR or boats. I have this motor in the junk box for a ??? project. I also have the 32 cc version with the clutch. These motors dont have the power needed. You can use them but you would have to gear way down to use the motor. A commercial motor is better :Echo $150 or Homelite $$$ with a clutch. For drive train parts I custom made everything. 1/8 scale parts are too small to handle the load stress these beasts put out. Everything needs to be bigger than 1/8 scale but small to fit in the size you choose for final dimensions. Zenoah are the best $240-300 with half clutch. you will need to buy the other half or make it the way you want. Chain saw motors are the best because everything is their but the RPM is the only loss. Weight is the biggest issue!!!!! and Money!!!!

A Reverse transmission is a luxury in the beasts.I designed it and built it!!!
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Old 06-20-2006, 05:57 PM
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you may have noticed this, but if you take the flywheel off, you will need some way to power and time your spark plug because that is dependant on the Fly wheel. explanation incase you are more curious.
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Old 06-20-2006, 06:33 PM
SoonToBeLowS10 SoonToBeLowS10 is offline
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You can get an MSD Kicker IGN. like used on Go-ped's, But then you'll either have to drill / fit one of thier RC/G2d/G23lh flywheel's, or find other mean's of cooling the motor [Probably the better alternative, But expensive when i could find / build a g230rc, for around $75. Plus instead of going stock, I could throw in some goodie's.]
Even a G23lh [1.25hp stock i believe..] would work, and are often cheap on Gopednation.

If you wanna go brand new,
230rc clone; http://www.davesmotors.com/store/product704.html ,
cy27rc W/ Inner clutch $169 http://www.davesmotors.com/store/product1506.html,
gp290 clone http://www.davesmotors.com/store/product929.html .

I'd suggest going Zenoah [Or a clone], either new, or used. That new cy27rc W/ inner clutch is a good deal. If you dont go Zenoah [Or atleast another motor set-up like it.], Your gonna spend way to much.
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Old 06-21-2006, 01:55 PM
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Quote:
Originally Posted by Figit090
why use a transmission? dont you have a clutch on that thing with a sproket? i would think you could just take that and run a chain drive to the rear axle and do a simple trailing arm setup. I dont know what i want to do yet...i was thinking of just that but...not that you mention it...

I would use any tranny out of a dual engine-capable truck, or somehow rig up the clutch on the chainsaw engine to mesh correctly with the spur attached to a 1/8th scale ALL-METAL differential or center spool which would then move to the rear/front just as in a 1/8th.

what do the people that HAVE done this think? i think more than one person here needs help with this. gear ratios are also going to be an issue. i'm going to go snap some pics of my motor.



can you please give more info on the transmissions and other aspects that you might think are vital to our designs? i'm interested mainly in the drivetrain design and what components were used in your truck. power handling, like mentioned...is a bit of a concern compared to a 1/8th or smaller...

yea, true a chain would be the easiest, but what about a mountian bike chain and stuff, think about it, just get a servo to pull that lever, and it can switch gears, i mean it would work, that little engine doesnd have more torque tan me, lol, and that is 5 or 6 gears, but that might be to tall, so it woulden be that fast, i dont know, ill look into it
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Old 06-22-2006, 09:56 PM
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Quote:
Originally Posted by Out Of Control
i jut got a chainsaw engine, and i was going to make this thread, but you got here first. and i was designing a buggy,

my dad raced go-karts YEARS ago, using a chainsaw engine, roughly a 38cc if i recall, and with a tuned pipe, ect, single karts would break 65-70 mph, twin engine...100mph +..........and that is hauling MINIMUM 350 lbs,....Good Lord, in something under 50 lbs???? YIKES!!!

but, OMG fun!!!!!
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Old 06-23-2006, 05:54 PM
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HOLY CRAP!!!!!, but yea, i think its only 20cc, but i think its the same as a weed eater engine, aint it?, i always thought it was
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Old 06-23-2006, 09:20 PM
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well thanks for all the posts, i really appriciate it.

The flywheel issue is a relatively big one. i would have to purchase a new magneto setup... that is a problem.

Since this engine isnt that strong (as mb said) i think 1/8th stuff would be ok...if not i would just use parts i make myself and neglect the use of a differential. I could run a shaft from the engine's output to the rear axle which could be a spool...avoiding some strength issues with spider gears.

but anyway, after further thought i've realised the motor i have isnt adequate for what i would like to do...i would have just built a smaller truck but unless i can get cheap parts to allow a clutch on my engine it's just not going to work. thanks for all the help... I was going to continue with this but i was going to on the basis of being able to use this engine. maybe if i figure out a practical cheap mod to allow clutch use. i was considering mounting a remote clutch, or one at the very end of the shaft. if i can figure out some way to get the clutch to work i will continue to pursue this but from your posts i guess its not really a good idea....
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Old 06-24-2006, 02:28 PM
jc2stroke2 jc2stroke2 is offline
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i put a chain saw engine on a tmaxx once i didnt work out that good i just kept breaking everything,jared
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