Operational Engine Stand

Discussion in 'Motorized Bicycle Welding, Fabrication and Paintin' started by jolfstn, Jun 23, 2015.

  1. jolfstn

    jolfstn Member

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    I have an extra HT motor and am considering fabricating a stand for my engine that will allow me to actually use & run the engine in order to test out modifications before putting it on my bike. I was thinking about a chain driven flywheel to give it a little resistance simulating actual use. Has anyone seen or made anything similar? I did a brief search and turned up nothing. Not a welder so a bolt up situation or maybe wood, or a combination. Juice Moto has a Youtube for a stand for working on your engine off your bike that could be a start but I am thinking something more involved. Any ideas?

    I've been away some time. I just got a new motor from Bicycle Motor Works, this is the 3rd I've purchased from them, as well as some parts and lots of advice from the proprietor, Matt who's very helpful. Give him business he deserves it. Good products good prices and great service. (unsolicited just a happy customer)

    My last one ran over a year before unknown problems inspired me to buy another one. The old one I'm thinking of building the stand for and getting it to run again that way. A year of almost daily use isn't bad considering its' a $100 piece of machinery composed of 115 year old technology. Happy motoring and any ideas on my operational stand would be helpful
     
  2. 2door

    2door Moderator
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    Any stationary engine stand needs to incorporate some means of cooling. These are air cooled engines, especially the Chinese 2 stroke engines which do not have cooling fans built in and rely on air passing over the cylinder and cylinder head for cooling.

    Some 4 stroke engines are designed for stationary applications and have internal cooling.

    You'll have to provide some moving air passing over the engine when it is running. Keep this in mind when designing an engine test stand.

    Tom
     
  3. jolfstn

    jolfstn Member

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    an excellent point Tom. I hadn't though of that. A small powerful directed airflow onto the fins should buy me a little use time I would think, I could also ad a temp sensor to the cylinder so that I can cut it off if it gets over a per-determined temp (thinking 315c-ish) a user of this group has a base for sale designed adding a HT engine to a chopper style bike I'm thinking of building my stand off of, he's offering a great price. Maybe I could have the motor turning the fan blades used to cool the engine! I just thought of that. I've received some great design ideas via PM from some users as well as advice and offers for parts. Thanks to all. I'll be sure to post pics when I get the project underway.
     
  4. 2door

    2door Moderator
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    Just an idea but I use the fan section from a residential size gas furnace. It also serves as a garage air circulator. It sits on the floor and I can direct the air flow toward the engine. My fan has a two speed motor, high and low. When I use it for engine tests I run the high speed fan. It's about the same as a bike moving forward at 20 MPH.

    Tom
     
  5. MEASURE TWICE

    MEASURE TWICE Well-Known Member

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    You might try heating the air that is moving from the fan to 95 degrees. Sort of joking, but my Briggs 3hp 4 stroke off road bike trail riding lost pretty much all its power after riding in that kind of heat after an hour or so. Letting it cool, I started it up and had the power back again. Maybe even with the flywheel fan and shroud with cylinder fins this was too much for it.
     
  6. Davezilla

    Davezilla New Member

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    I made a stand for mine out of a piece of 1 1/4" steel tubing welded to a 1/2 steel plate so it can hold the engine for display on the counter at my shop, but it can be c clamped to the welding table for working on the engines or even doing test runs. For cooling you can use one of those squirrel cage fans like the blue blower or those yellow Stanley garage fans since they put out a lot of air in a small area. You can buy a pull starter to start the engines or put a wider nut on the mag rotor and start with a cordless drill, don't try this with the standard nut or it'll strip tho.... for fuel I just use a pocketbike tank hung above the engine. What I want to do next is find a way to put a load on the engines so I can run them in or at least partially run them in before installing. I've been thinking about getting a used portable generator and taking the engine out so I could install a sprocket and then use it as a dummy load for the engine by running a fan to keep the engine cool and some halogen lights to put a load on the engine and this could be automated further with a laptop and a set of servo motors to operate the throttle along with a temp sensor so it could auto shut down if it started getting too hot. Right now I don't have the time to make something like this but if things slow down this fall and winter I should have enough time to build a setup like this to run in the engine before it goes into a bike frame, but for now, just having a stable stand and a fuel supply with a fan blowing onto the cylinder is enough to start, run, and do some minor tuning. Right now I use it mainly for displaying but it works great for setting up a new engine.
     
  7. jolfstn

    jolfstn Member

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    That's exactly what I'm hoping to do, hadn't considered the servos and laptop idea, but if my dream of adding an Ecotrons EFI to one of these it would be necessary wouldn't it? Would you mind terribly posting a pic of the stand you have now? I would love to see it.
     
  8. Davezilla

    Davezilla New Member

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    Here it is in all it's simplicity, to actually run an engine on it it needs to be C clpmped to a work bench and a pull starter installed, then to feed it, I just use an old IV stand with a pocketbike tank and a line to the carb. I just use a shop fan to keep things cool if I'm running an engine on it, but I use it mostly for assembly or setting up port timing etc...

    [​IMG]

    [​IMG]
     
  9. LandSpeedRecord

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    I repair carpet cleaning equipment and truck mounted units for my day job. The carpet cleaning and restoration industry has extremely powerful squirrel fans both small and large that are inexpensive for what they are. I keep thinking of looking on craigslist for a cheap used stationary exercise bike that I can modify and beef up the load applying mechanism and use it as a makeshift dynomometer. In theory it should be realivly easy to come up with a way to mount a bike motor to it and potentially with enough air flow fully tune motors on it. By cutting off the seat, handlebars and such it could be bench mounted also..
     
  10. LandSpeedRecord

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    Oh and Dave, don't think I didn't notice the turbo sitting by your motor on the stand. How do you plan to feed it oil with the China girl? I have thought maybe a convertible top pump from a car run off a Lipo pack? My current turbo thoughts are to make a really small one with ceramic bearings and hope to not run oil in it. Feel free to PM me if you don't want the whole forum to know that turbo is for the CG I can keep it secret.
     
  11. Davezilla

    Davezilla New Member

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    I think that turbo is a little much for a cg engine... I was going to put it on my Nissan 4x4 pickup to give it a little extra power but about the time I had all the parts I needed to do the job the engine started knocking so now I'm looking at rebuilding a 4.0 ford v6 and getting a 5 speed from an explorer sport or mustang. This will definitely give the little truck some decent power but now that turbo is to small to feed the 4 liter v6, but I got a customer who has a first Gen 300zx who thinks he blew his turbo and I may sell it to him and help him install it since it's enough to give his car a nice boost over the stock turbo it has. For the 4.0 I'm putting in my truck, I'm thinking more on using a gm style supercharger off a 3.8 like the Pontiac Bonneville ssei or maybe one off an 89 thunderbird super coupe. This will be more compact and much easier to make up an exhaust system than turbo charging. I'm also planning on turbo charging a Buell blast using a garret gt 15 or ihi rb31 turbo, these bikes have about 35hp stock but lots of torque so they don't feel sluggish at all for their size, but that power could easily be doubled with the right size turbo.
     
  12. LandSpeedRecord

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    I really like these vs21's. http://m.ebay.com/itm/331596894632
    They are tiny, they work well on 600cc I just wonder how small of a motor would spool it. There is a company making a legit supercharger for 50cc Honda's I would just like a tiny turbo suitable for our bicycle size motors. I have a few pieces gathered up at the shop to build one but have not come up with realistic compressor wheel although I think I have a viable turbine wheel and housing. All seriousness aside you should attach that big turbo on the desk to the CG there is nothing better than a turbo bigger than the motor ha ha.
     
  13. Davezilla

    Davezilla New Member

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    Garret makes a turbo even smaller than the vz22/ rb31 that they claim an engine as small as 100cc can spool, it's the gt06 and it has a 21mm inlet with a 32mm compressor wheel so it's tiny, I've seen the specs for it on garrett's Web site and it claims to push enough air to make about 80hp.
    The vz22/rb31 is slightly larger and can be spooled by as small as a 100cc engine so it would work on a pred212 but we're still talking about maybe doubling the stock horsepower at 15psi boost, but with a turbo cam, lower compression ratio, billet rod, and run on race fuel it could make up to about 30hp from the 212, but most people would get between 10 and 15hp or blow the engine by getting too greedy with the boost but not want to spend the money to do all the other upgrades.

    I've been thinking about using a gt15 or rb31 turbo to boost my Buell blast up to around 55 to 60hp, which would be enough to make that bike really fast without blowing a rather close to stock engine. It may need lower compression and an ignition curve that could retard the timing as boost goes up as well as a way to feed the right amount of fuel to keep from going lean under boost. The Harley 40mm carbs do work well for blow thru systems by using an electric fuel pump and a boost sensing pressure regulator, then using a pitot tube in the boost line to pressurize the bowl vent it will force the right amount of fuel thru the main jet once tuned right. These carbs also work well for draw thru setups but with draw thru there are other problems to overcome and you can't run an intercooler.

    For trying to turbo or supercharge a 2 smoker it can be done but there is another set of rules to flow since the expansion chamber acts as a supercharger one needs to make more boost before any increase is noticed, I've seen a turbo banshee set up for drag racing and it too, 8 psi to make the same power it did stock or un boosted, but above 8 psi it became wicked fast. It's been done way back when Detroit began making 2 stroke diesel engines for trucks and heavy equipment, but they used a blower mainly to blow the air into the cylinders and not for boost since the cases couldn't be used to draw in the fresh charge, these weren't originally designed to make boost but they did find their way on top of flathead ford's and the rest was history. Detroit did make "high power" versions of their 2 stroke diesel engines tho by adding turbos that blew into the blowers, they also incorporated an exhaust valve to keep the fresh charge from simply blowing right out the exhaust. I've also seen some 2 smokers that had a wall on top of the piston to help keep the charge in which worked at higher rpm but not so well at low rpm since there was enough time for the charge to go over this little wall and out the exhaust similar to why an expansion chamber works best at a certain rpm range but not as well above or below the range it's tuned for.
     
  14. LandSpeedRecord

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    The Buell sounds like it will be a really cool project. I am somewhat familiar with blow thru systems on 1rst gen RX7's but they have been done so much there is all the info and parts already out there. I realize that making a turbo work and even be ridable on one of these will be a huge challenge. I think it will be a bunch of fun though. Right now all my spare time is going into getting a small bike business going so I can devote a lot more time and energy into things like a turbo 50cc bicycle. I should think about gear driving it also then it's technically a supercharger but that makes some things easier. The problem is I have piles of parts on my work bench to get me part way there ha ha.
     
  15. LandSpeedRecord

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    There is also the way I cheated with my China girl and run nitro methane blend but that was just to make power. I want the forced induction on a Huasheng more for the engineering challenge and fun than power. If I can make 5 horsepower with it that would be awesome.
     
  16. Davezilla

    Davezilla New Member

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    You could probably run a GT06 turbo on a 50cc engine since it's a really tiny turbo but the biggest problem there is the price at $699 per unit and there are no clones of it out there yet.
    The main problem you'll run into by using a turbo that's too big like the RB31 on a 50cc engine is that it won't start to spool until the rpm is way up there... sort of like those Hondas that are using 18 wheeler sized turbos on a little 1.5 to 2 liter engine, yes, they will make around 500 to 600hp but won't come into play until the engine is close to redline, then it has a really narrow but really strong powerband.
     
  17. LandSpeedRecord

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    Only making high rpm power may be manageable if I can get the clutch and gearing set up right. A narrow powerband make single speed tough either way though. I still really like the Sturmey Archer fixed 3 speed as a jackshaft that I have seen Cannonball set up on here. That could all work. The price matters of course although I really want to build one myself. That said I will probably spend more building it than buying one. Maybe the way is to start with an RB31 and try to modify it to spool as soon as possible. I want to narrow down a direction since I am buying some parts for this build next week.
     
  18. Davezilla

    Davezilla New Member

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    If you got the means to balance the shaft on an rb31 I'm sure you could make one work by lightening the turbine and impeller wheels up considerably, learn the trim numbers and letters and what each trim's strong and weak points are... the Q trim on the turbine side reduces the weight and rotating mass quite a bit but it's not the most efficient trim either, but may be a necessary evil since it's one of the lightest trims... find out what the lightest trim is and you may need to explain to a turbo builder just what your trying to do and they might be able to get an rb31 or gt12 light enough to spool and maybe even have smaller housings available with a tighter ar ratio that can spool better off a really small engine. I know the larger more common size turbos can be set up to spool with the least exhaust restriction by swapping out the turbine and compressor housings but that's more of a "fine tune" once the right compressor and turbine wheels are selected, I'm not sure if all this is readily available when dealing with these tiny turbos, but if so, then this might be the key to getting one to work on a 50cc engine.

    if you want to go the supercharger route, there's a guy who builds mini v8's with roots type blowers that work, I dunno how much he would sell just the blower for but it may be close enough to the right size for a 50cc engine, considering these are kinda novelty for the rc world they may be too pricy to consider, but a belt driven compressor wheel and housing off a small turbo could be made to work something similar to a vortec or pro charger where the compressor wheel spins about 5x the engine rpm or more.
     
  19. LandSpeedRecord

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    The compressor side of a tiny turbo driven of the motor is probably the best option now that you say it. The Vortex and like are well proven and I think the layout has a lot of advantages. The shop that worked on my race bike installed that type of set up on a v-twin Harley and it worked well. Might need to achieve a pretty big over drive ratio off the engine? Say spin the motor at 10000 would the turbine build enough boost by 50000? I find surge charts a little confusing even though I have stared at them enough hours. Most are at peak efficiency between 100000 to 150000 but I'm only looking for 3 to 5 psi at most sp maybe 50000 or a bit more would work. I have seen electric driven turbos work with that kind of over drive so I know it is possible. I think the motorcycle set up actually ran off a belt but I always lean toward chain and gears because it's what I know.
     
  20. Davezilla

    Davezilla New Member

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    For a really small turbo like the rb31 or gt12 it may need to turn at least 100 rpm to be efficient and make boost, but on a small engine like a 50cc, you could probably achieve that kind of rpm by over driving the compressor wheel By 2 or 3 to 1 and powering it with a high powered brushless rc motor that can spin at close to 50k rpm, I'm thinking an rb31 compressor wheel and housing could be attached to a cog type pulley and belt and run off an rc motor it should be able to spin the wheel to 80 to 150k rpm with the right gearing. You may even find a way to gear drive the compressor if a small cog belt isn't strong enough or efficient enough, a little straight cut gear whine may also be pleasing to the ears when running too... I'm thinking the use of a cog belt and pulleys would be the easiest way to get the right drive ratio since they are readily available from cnc suppliers, just be sure to use a belt guard of some sort or stay out of the plane of rotation because if it throws the belt at that speed it's gonna hurt just a little more than getting a rubber band shot at ya...
     

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