Engine upsidedown

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BOATCH
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Engine upsidedown

Postby BOATCH » Mon Dec 08, 2008 4:23 pm

Is there a way that the skyrangers motor can be turned so that it stands up right .If i look at the cheetas motor it is the right way up,and what would the pros and cons be of rotating the motor and will it make a diff on the weight and balance.
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Morph
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Re: Engine upsidedown

Postby Morph » Mon Dec 08, 2008 4:25 pm

Why do you want to do that? The motor can run perfectly upside down
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Re: Engine upsidedown

Postby BOATCH » Mon Dec 08, 2008 4:32 pm

Yes it has been running upside down for 70 od hours but can not seem to get rid of the oil leaking out of the manifold gaskets .All the right side up motors are clean and this is like driving a mini you always park outside a friends yard cause you do not want to mess up his paving :oops:
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Re: Engine upsidedown

Postby Stephan van Tonder » Mon Dec 08, 2008 6:26 pm

The cheetah has a very different cowling with that big hump on top which gives you the space. The engine mounting is also probably lower. To do that you probably have to re-engineer a couple of things.
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Morph
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Re: Engine upsidedown

Postby Morph » Tue Dec 09, 2008 8:18 am

Strange, I had Challenger for about 200 hours with an inverted engine and never had a problem.
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Re: Engine upsidedown

Postby Wargames » Tue Dec 09, 2008 9:00 am

I don't think the way your engine is mounted will change the outcome of your oil leak. Rather replace the manifold gaskets, and then re-torque every 10 hours. As you fly the gasket do give way, and you need to keep your hand on them not to leak!!
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BOATCH
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Re: Engine upsidedown

Postby BOATCH » Tue Dec 09, 2008 9:12 am

I wil order a new set of gaskets and fit them and see if it solves the problem. I thought the gaskets are only there for the exhaust gasses, but on the other hand this is 2 stroke and after the motor has been switched of the oil and feul that has not burnt will seap out if the gaskets are not sealing propperly. :idea:
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Re: Engine upsidedown

Postby Morph » Tue Dec 09, 2008 9:20 am

Yes the only problem with the inverted motor is the heads have more gunge build up due to the unburned fuel and oil sinking to the top (now the bottom due to being inverted)

I never had any starting problems and the plugs, never looked more clogged that those from a normal motor

I would agree with Wargames, the fuel/oil will seep out a lot quicker when under compression than by gravity alone.
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Re: Engine upsidedown

Postby Wargames » Tue Dec 09, 2008 9:38 am

The problem we are talking about is somehting that is created by the design of the 2-stroke engine in that the exhaust is not only a tool for silencing the noise, but also to give power and make the 2-stroke work. The exhaust build up presure as to create a bit of extra compression in piston, and that there is not a free flow of air out of exhaust. This cause the compressed air to look for openings to get out of system, and the manifold gasket is normally a nice place to do that.

Remeber, the exhaust port is in the middle of the cilinder wall, thus gravity will not have any efect on the leak. On inverted engine, you will however flood your engine more easily, but that is about the only down side, the rest is the same for upright or inverted engines.

Have a look at this link. It will show you the workings of a 2-stroke, however, it does not explain the importance of the exhaust.

http://www.youtube.com/watch?v=LuCUmQ9FxMU
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