fr0st

I'm interested in making my own rotary and have pretty much looked at every site possible for info.
Although I'd be making smaller ones to start with i may work up to car standards (dout its liscencable tho , theres always go karts)

First of all, I found the cross section of a two rotor motor but it comes with no dimensions. Assuming its a 13B, how wide would the rotor be?
(picture attached)
Second, What would you recommend it have in the way of valve sizings, rotor sizings, apex seal material etc. ?
any surgestions would be great

I havn't had time to go through the forums looking for threads related to performance mods as yet.. but i will soon!

Thanks in advance
Matt

Jeff20B

iTrader: (13)

That's not a 13B. I also don't like the spark plug location. It also looks like a front wheel drive setup, or an inefficient use of underhood space for the oil pump or whatever (see the odd outcropping under the spark plug).

Is that an NSU engine?

Man, that spark plug is practically in the trailing position. Yeesh!

fr0st

I have no idea of the make/model of the engine... I can't even remember the site I got it off.
In relation to the spark plug, should it be high or lower?
If my engines ever get big enough it going to need two plugs, but that can be crossed when i get to it.
As a reference, how big are 13B rotors?

Thanks
Matt

peejay

Yah, that's an oddball all right.



I don't think it's an NSU production engine, those had *two* peripheral intake ports, there would be a second, smaller primary port mounted above the intake port you see there.

So what is it? Fichtel/Sachs? Citroen? Other?

Jeff20B

iTrader: (13)

I bet it's that FWD rotary. That must be the reason for all the bulk under the spark plug.

About the spark plug, I'd move it lower and spark it once at TDC/0º and again at 180º because it takes care of the trailing edge of the combustion gasses (squish, as it's called), and actually increases power while decreasing emissions. Not to mention it's extremely easy to go direct fire if your distributor is already set up for two rotors, like Mazda's is. Even with one rotor, it's still piece of cake.

All I need to build myself a one rotor 13B is the custom E shaft. Oh, and the intake and exhaust. I'll run my ignition as described above.

fr0st

are you machining everything?
I love to know how you go once its assembled

a basic question...
The rotor orbits around a stationary gear right, is the rotor gear a larger diameter than the hole for the essentric shaft?
and...
is the essentric gear free turning inside its hole in the rotor?

-Matt

rotaspec

The stationary gear is fixed to the side housing, not on the eccentric shaft, is about the same size as the lobe on the e-shaft that sits in the rotor bearing. It has 17 teeth on its outside diameter.
The rotor gear is much larger and has 51 teeth on its inside diameter. That gives the 3:1 ratio of e-shaft to rotor speed. It is fixed to the rotor.
The two gears give the rotational portion of the rotor's motion. The lobes on the e-shaft (something like a cam but symmetrical) give the reciprocating portion of the motion. The two combine to give the trochoidal motion needed to trace the 'figure 8' motion needed to perform the Otto 4-stroke cycle within the rotor housing.

fr0st

ah thanks I have a very clear picture of how it works now.
Is there an actualy bearing for the lobe inside the rotor or does it rely on oil to not the wear and tear?
Also, are similar materials used to the seal the rotor to the side housing like the apex seals?

Your answers are very much appreciated

RacerXtreme7

iTrader: (2)

What you want to know about basic rotary engines. It always helps to have visual aids along with the text.

http://www.rotaryengineillustrated.com/

~Mike.............

rotary emotions

I think the above pictured engine could be a Citroën. To be clear: Citroën engines were NSU ones! The only difference is the fact they mounted the engine transverse, where as NSU had it in-line.
However, NSU did a lot of research, and has built numerous of prototypes.
to see a line-up:
http://www.der-wankelmotor.de/Motoren/motoren.html
This should pretty much list any Wankel-engine ever build.
I personally own a NSU, but didn't (yet) open up the engine.
It can all be rather confusing, since so many different designs have been tried.