Another Karl Benz 1886 Engine and Motor Wagon.

[Ken Brunskill]

I am very sorry for my delay in replying.
There is a gap of 33.5 mm from the top surface of the piston to the top end of the sleeve, @TDC.

I am very sorry for my delay in replying.
There is a gap of 33.5 mm from the top surface of the piston to the top end of the sleeve, @TDC.

Wow, that is quite a gap. I have designed the piston to be at TDC when it is just below being tangent to the Spark Plug hole (toward the crank), which I have at .280" (7.1mm) from the top (Head end) of the Cylinder and Liner. I'm making the Liner shoulder wide enough to have the Spark Plug thread through the Cylinder and Liner + a bit for material strength.

I just about have the 3D modeled in Solidworks, with all parts moving as they would be in the operating engine (learning as I go) now to get the cam to compress the Exhaust Valve Spring and I'm there, I think :-| !!!

 

[Ken Brunskill]

Ken.
As you are making this from scratch at a smaller scale you should know that the design, as is, gives a very low compression ratio. Something like 2 - 2.5 : 1. This is insufficient to make the engine work consistently well. You should design the head with a spigot rather than a recess and maybe increase the piston length in order to increase the compression ratio to at to 4.5 - 5 : 1.

Tony,

At the moment I have the stroke at 1.500" (38mm) and a .875" (22mm) OD piston. I've yet to work out what the volume is in the head cavity where the Exhaust Valve lives, with your comment, I will put that on the to do list.

 

[Swenjoy]

I am progressing well with my engine, i am currently thinking of what fuel is used or fuel mixture, could someone please advise me also am thinking about the ignition system, i am not an electric/electronics type of person so as much help in this field would be greatly appreciated.
in anticipation
Swen
Australia

 

[rutzen]

With these low compression engines the fuel doesn't seem to matter much. I just use ordinary unleaded in my Rumely tractor engine and that works fine.

 

[Jasonb]

I tend to use Colemans fuel as it does not smell as much as petrol.

 

[awake]

I too use the Coleman fuel. Occasionally I mix in just a bit of WD-40 to provide some internal lubrication; others here tend to run a mix all the time.

The basic idea behind most ignition systems is the use of a coil to generate high voltage, along with a way to induce and then break current in that coil. When the current is broken from the coil, the built-up electromagnetic force wants to go somewhere - and it is allowed to go through the spark plug. So here is a simple, mostly mechanical system:

A coil has its high-voltage output connected to a spark plug, and one lead connected to 12V and the other lead connected to a set of mechanical "points" - simply a momentary switch. The switch is connected to ground (usually via the engine itself). The cam shaft on the engine has a "flat" on it that allows the switch to close, completing the circuit in the coil and allowing it to charge up. Then when the camshaft turns to the point that the flat transitions back to the round, the switch is opened. This breaks the current in the coil, and as described above, the result is a high voltage spark from the high-voltage output, through the spark plug. The timing of the spark is controlled by the placement of the points (switch) relative to the flat on the camshaft.

There are additional refinements, starting with a condensor (basically a capacitor) attached to the points (switch) to help improve the spark and reduce wear on the points. Automobiles with this type of ignition would have a vacuum line from the engine that would adjust the ignition timing in relation to the speed of the motor.

One can replace some or all of the mechanical components with electronic components. For example, instead of points switching the current on and off, one can use a transistor. Instead of a flat spot activating the points, one can use a magnet and a "hall effect transitor," or some sort of optical switch, or other means to time the spark. Some electronic systems charge up a capacitor to deliver the spark. And so on ...

I would encourage you to spend some time reading through Wikipedia or other sources on ingition systems, and study the plans of some engines to see how they are implementing the ignition. I hope this is helpful ...

 

[minh-thanh]

Hi Swen !
As Andy said, there are many types of ignition, you choose one , then it will be easier if you need help .

 

[Thommo]

I am progressing well with my engine, i am currently thinking of what fuel is used or fuel mixture, could someone please advise me also am thinking about the ignition system, i am not an electric/electronics type of person so as much help in this field would be greatly appreciated.
in anticipation
Swen
Australia

Hey Swen, any chance of some happy snaps of your engine?

 

[a41capt]

I can’t answer any questions regarding the electrical beyond an ordinary points breaker system with coil, condenser, and battery. However, especially during early break in, I use Coleman fuel (lighter hydrocarbons) with a small amount of Blendzall Green Label castor. I’ve found that, much like my old 2-stroke race bikes, compression is improved prior to the rings being thoroughly seated by a relatively rich mixture of a good two stroke oil. I prefer the plant based castor oil even though some claim it forms a gum or varnish. A side benefit is the great smell!

John W

 

[Swenjoy]

Thankyou so much for the many replies, i will try to post Photo of where i am up to, Thommo are you making this model?

 

[Swenjoy]

I too use the Coleman fuel. Occasionally I mix in just a bit of WD-40 to provide some internal lubrication; others here tend to run a mix all the time.

The basic idea behind most ignition systems is the use of a coil to generate high voltage, along with a way to induce and then break current in that coil. When the current is broken from the coil, the built-up electromagnetic force wants to go somewhere - and it is allowed to go through the spark plug. So here is a simple, mostly mechanical system:

A coil has its high-voltage output connected to a spark plug, and one lead connected to 12V and the other lead connected to a set of mechanical "points" - simply a momentary switch. The switch is connected to ground (usually via the engine itself). The cam shaft on the engine has a "flat" on it that allows the switch to close, completing the circuit in the coil and allowing it to charge up. Then when the camshaft turns to the point that the flat transitions back to the round, the switch is opened. This breaks the current in the coil, and as described above, the result is a high voltage spark from the high-voltage output, through the spark plug. The timing of the spark is controlled by the placement of the points (switch) relative to the flat on the camshaft.

There are additional refinements, starting with a condensor (basically a capacitor) attached to the points (switch) to help improve the spark and reduce wear on the points. Automobiles with this type of ignition would have a vacuum line from the engine that would adjust the ignition timing in relation to the speed of the motor.

One can replace some or all of the mechanical components with electronic components. For example, instead of points switching the current on and off, one can use a transistor. Instead of a flat spot activating the points, one can use a magnet and a "hall effect transitor," or some sort of optical switch, or other means to time the spark. Some electronic systems charge up a capacitor to deliver the spark. And so on ...

I would encourage you to spend some time reading through Wikipedia or other sources on ingition systems, and study the plans of some engines to see how they are implementing the ignition. I hope this is helpful ...

Thankyou very much

 

[Arild]

Having got inspired by the thread started by gg89220, I purchased the castings from TS Models-Germany, and started work. As some time was spent before the castings arrived, I thought of doing some work on the Wagon. I contacted TonyM, who also was showing interest in gg89220's build, regarding constructing the Wagon. After a few communications I constructed the wheels first.
View attachment 116077
View attachment 116078
View attachment 116079
The tube frame was formed, and by that time the castings were received.
View attachment 116080
Pictures of the engine construction will follow soon.

Impressive! But how did you make the rim and rubber? Or is it available some place?

 

[Jasonb]

Your previous batch of posts got me interested in this engine and I started to look at the TS model but it soon became apparent that there were quite a few deviations from the original so I started to draw it up from scratch but got side tracked with other projects. maybe seeing your progress photos will inspire me to do a bit more work on my redesign.

 

[Arild]

The castings are mostly aluminium. Reasonably good quality with no porosity, Spigots etc. are well positioned so holes are relatively central. Flywheel and base are CI. The flywheel had no hard spots and needed minimum fettling. Altogether very pleased with the result. I wanted to make mine nearer the original so have made a few mods to the plans. The camshaft gears being the main one. Mine is the same orientation as Edwards

Is there a place I can get only the drawing from?

 

[redryder]

Looking for a set of castings and drawings for the 1/3 scale Benz Engine if anyone in the USA would let go of them.
Gil