new crankcase design help and input!

[ipwnr]

hi guys i got a friend that works at a machine shop and mechanic shop and he told me that if i can come up with a design he will try to get access to the cnc.
and I'm not really good at designing engines so thats why i came here. i just want to design a crankcase that will take polini or puch moped engine parts and that will still bolt onto a bicycle with the same mounts or stronger style mounts i would also like it to incorporate a water pump for liquid cooled jug and head. so basically i just want to get 1 crankcase built for testing and personal use and if it works out good and if it show good number on a dyno (that i still have to find) i might think about re-sale. so please can some one help make plans for this for me or point me to the way so i can do it by my self because i don't know what program to use and I'm not all that good in auto cad. and any other ideas you guys got please throw them out here i would love to incorporate it in the engine.

 

[ipwnr]

no one has any input???

 

[chevelle454]

Watercooled is a lot of work for such a small engine, driving the water pump will take quite a bit of power. Look at most motorcycles, they are aircooled. The benefits would be outweighed by a higher weight and size, and unless you are past the limits of aircooling, less power. I am an engineering student/restoration specialist with access to cnc and a complete machine shop. I have been designing a supercharged 250cc supercharged flat 8 for about 2 months now, which i will mill. THERE IS A LOT OF WORK that goes into designing a well running, reliable motor. Stress analysis, vibration analysis, math, math, and more math.

 

[mew905]

if you're just looking to water cool the head, I imagine you could buy some thin copper pipe, drill some holes through the fins on the jug on each of the corners close to the head, and run the piping through the holes (small pipes, like say 1/4" to 3/8" OD, maybe smaller?), then connect them to a computer water cooling pump and a 2x120mm or even 3x120mm radiator. You wouldnt need fans as the bike moving would handle that. might be a cheaper alternative, only issue is I'm not sure what the bike motor's output is, I know the white wire is 6-9v RPM based, but obviously a computer setup would ask for 12v, and a couple amps (I'm not sure what amperage you would get converting a bike to constant 12v).

 

[BigBlue]

RC boats are water cooled, but other RC vehicles are generally not water cooled. Boats don't have the airflow to cool the engine. What is the purpose to cool the head? Wow factor? or a specific goal that you want to accomplish. If you want to do it, just because you can, then go for it, but don't expect others to jump in without any specific reason or benefit.

As chevelle454 stated, motorcycles are mostly air cooled and our small engines do just fine with the flow of air cooling the head.

Good Luck,

Chris
AKA: BigBlue

 

[ipwnr]

yeah i just wanted to build an engine that would put out 10-15 hp or more and i wanted to play around with it and put it on a bike. and yes for the wow factor and to also reach 100kmh, thats basically my goal

 

[Mike B]

Good luck.

 

[chevelle454]

10-15 hp will be pushing the limits of bikes, i believe. ****, most can't handle the paltry few hp and ft/lb of the china girl. Honestly, i dont like to be a total downer, but a custom made case to fit pre-built parts is rather asinine... It would be at least as expensive as a puch, and at best, equal quality. Why not just make mounts to mount a puch motor?

 

[ckangaroo70]

If you are just looking for a fun project and know someone with a machine shop, how about converting a China Girl that runs on gas over to a glow engine that runs on methanol? Machine a head that uses a glow plug and figure out the carburation and compression needed to run methanol. Maybe go over to the RC Universe forums in the engine conversion forums to get some ideas. Guys convert Ryobi weedeater engines over to run on alky...so probably wouldn't be hard to get a china girl to do the same. Of course a China Girl running on methanol is not going to be very practical and fuel cost will be terrible, but hey....if you like to tinker...may be something you might find interest in checking into.

 

[rich4240]

a bike can take a lot of hp iv got my occ chopper puting out 11whp ate 125km/h no problem