Making Stuff from Garbage

GoldenMotor.com
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Radana

New Member
May 22, 2011
8
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Sweaty South
Hi everyone, I'm one of the new guys here and joined because I have a potentially dumb question to ask:

What about building your own motor from scratch?

I saw this guys website:

Secret Files

and that coupled with a weekend of watching The World's Fastest Indian has me thinking I could do something similar. I figure most people will say something along the lines of:

1) No, because you need to know what you're doing.

2) No, because it's not practical.

3) You need access to a machine shop/a Ph.D. in engineering, etc.

Let's throw out most reasonable logic. As long as you have the primary parts of an internal combustion engine (ICE), and the interior cubic volumes are the same as say something comparable to what's being attempted, is that all thats needed? What I'm thinking is this: alot of engines and motors I see at my local junkyard are damaged beyond saving as a whole. But what if you took the crank and piston out of an engine and put it in a housing with the same interior dimensional volumes? Say you make a crank housing out of some large tubing or piping and have some pillow blocks to support the drive shaft, and made the head out of some pipe with some cooling rings and bolt that onto the crank housing...shouldn't that all work? I know there's a few mechanical variables that I haven't accounted for, but more or less isn't my theory sound?
 
Pilotgeek

Pilotgeek

New Member
Apr 6, 2011
403
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Green Bay, WI
Hey, how did the first engines start? Someone had to kludge one together =).

I'm sure it's possible, but like you said, not very practical. There are a lot of things that need to be very perfect in a 2-stroke to run. The easiest thing to do is find a lot of broken engines that are similar, and just take good parts and build an engine. My dad does snowmobile repair, and sometimes he'll find some total crap engines someone threw away, and make a great fully functioning budget engine out of a bunch of what other people refer to as garbage.
 
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Radana

New Member
May 22, 2011
8
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Sweaty South
Pilotgeek said:
Hey, how did the first engines start? Someone had to kludge one together =).

I'm sure it's possible, but like you said, not very practical. There are a lot of things that need to be very perfect in a 2-stroke to run. The easiest thing to do is find a lot of broken engines that are similar, and just take good parts and build an engine. My dad does snowmobile repair, and sometimes he'll find some total crap engines someone threw away, and make a great fully functioning budget engine out of a bunch of what other people refer to as garbage.
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That's more how I thought going about it. Looking at the Acme V Twin , can a multi-piston engine run without a cam? Looking at theirs, its two motors running the same gear, but I dunno with timing and whatnot what other variable there are going that route.
 
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Radana

New Member
May 22, 2011
8
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Sweaty South
"the prussian" Shop Dogs said:
You need to read the story of the guy who built the motors for the wright flyer,sorry no time to look for the link ,boss watching. ;(
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I assume you're talking about the Wright Brothers? I checked some stuff out, looks pretty interesting.

A New Approach/Idea

My parents informed me that I still have some stuff at their house, among the stuff they want out are the two trimmer engines I have that I totally forgot about! One is a Craftman brand and the other is a Shindaiwa. So my question is, can I have both of these run the same drive shaft? I've been looking at drag bikes that have multiple engines and they use separate clutches and connect to a driveshaft which is in turn connected to the wheel sprocket. I'm thinking this is the best approach, but they are most likely different cc's (I think one is 25 or 27 and the other one is 23) and from different manufactures. I'd like to slave them together like the Acme V-twin does, but I don't know if this would work. Anyone's thoughts?
 
Pilotgeek

Pilotgeek

New Member
Apr 6, 2011
403
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0
Green Bay, WI
If you wanna slave two together, they should be timed so that they aren't fighting each other. This means they would also have to be identical. If you wanted to use multiple motors, belts between them or some sort of clutch is probably the best option. I have seen one setup where one engine drives the front wheel, and the other drives the rear.
 
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Radana

New Member
May 22, 2011
8
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0
Sweaty South
Mike B said:
That's why they invented 2 cylinder motors.
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Despite your sarcasm, I'll take that as an endorsement to the idea. So is having the engines fight each other the only problem? I think if they each had their own clutch attached to the same jack shaft they'd stay out of each others way, correct?

I've looked at how some folks have used smog pumps out of old cars as superchargers for small cc'd engines. Would having the same pump run to each engine cause too much trouble? I was also looking at those portable air pumps you get for your car, getting two of those and using one for each motor...
 
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gobigkahuna

New Member
Apr 25, 2011
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E NC
Another possible issue is vibration which could become much worse than a single engine if the strokes of the 2 engines aren't running at opposing cycles.
 
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gobigkahuna

New Member
Apr 25, 2011
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E NC
Sound and vibrations are basically "sine" waves and the noise / vibrations from an engine is often the combination of numerous sine waves, each at different frequencies and amplitudes. Consequently it becomes a very complex challenge to design a system where vibrations tend to cancel each other out rather than add or multiply with each other. I'll give you an analogy: If you've ever driven a twin engine boat you'd find that as the two engines approach the same RPM's the severity of vibrations change very radically and it often takes some delicate "tweaking" to set the engines so you get the lowest amount of vibration. On a boat the easiest method is to run one engine at a couple RPM's slower than the other. In your instance where the motors will share a common mount and drive through a common chain it becomes even more complex. One thing you might want to consider is to set up the system so you can easily try different settings, ie one engine slightly ahead or behind the other, to see how that effects the resulting vibration.
 
moonshiner

moonshiner

New Member
Apr 23, 2011
199
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0
tennessee
Radana said:
Harmonics? Care to elaborate?
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i am a musician i can answer this one ...
OK what Gobigkahuna is explaining is called Resonance , the loudest point of vibration , if you time or tune the engines off of each others freq it will dampen vibrations , cancel it out , like when they build these super span bridges , all of the cables and steel beams are different lengths for a reason , to dampen resonance , in case a earth quake or high winds , so the bridge dose not resonate and tear its self to pieces ..dnut
 
decoherence

decoherence

New Member
Aug 23, 2010
476
2
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sebring,fl
i see lots of vibration problems. having 2 cylinders on the same engine will be smoother than a one cylinder on its own because that are made to balance each other. on 2 different engines they will be 2 unbalanced one cylinders.
 
Goat Herder

Goat Herder

Gutter Rider
Apr 28, 2008
6,237
20
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N.M.
That's a very interesting bike would love to take it for a spin! Yeah To separated engines are definitely going to vibrate a lot more.
 
Pilotgeek

Pilotgeek

New Member
Apr 6, 2011
403
0
0
Green Bay, WI
Don't take this as a joke. Even if he ends up not being able to build an engine, he'll learn something from it =). The easiest way would be if you know someone who can machine parts and use autocad. With resources like that, you could definitely design whatever the **** you want. It's all a matter of how determined you are, and the resources you have.
 
Pilotgeek

Pilotgeek

New Member
Apr 6, 2011
403
0
0
Green Bay, WI
Oh, I'm sorry my85lamborghini. I did not see that you have 10 posts on this site, and therefore are an elite member. My apologies.

Seriously though, if you don't like the thread, I ask you to kindly ignore it instead of flaming it.

So with your logic... nothing would've ever been invented. Think about before the internal combustion engine. Sure, they had other things to work off like existing steam engine designs, but nobody had laid out plans for an internal combustion engine. You have to experiment and learn. This guy isn't even necissarily going to make something out of nothing... he might take old engine parts and build a functioning one. Let's say you have two similar engines, and both have different things wrong. Why not mix and match the parts to make a functional one out of two?
 
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