Inspired build of the Benz 1886 Engine

[Martin Hampton]

As promised this is the other side of the engine showing the cooling water return line.
View attachment 148779

This little part took quite some time to make. It is the bracket that holds the hall sensor. I wanted it to be adjustable so the curve matches the OD of the flywheel. I installed a magnet in the outer rim of the flywheel to activate the sensor.
View attachment 148780

Thanks for looking
Ray

One that I built a few years ago.

 

[Rdean33422]

Looks very nice.
A huge project

Ray

 

[Martin Hampton]

Looks very nice.
A huge project

Ray

Yes but also very interesting. The other side.

 

[Rdean33422]

The ignition is complete and sparking.

Hall sensor pickup on adjustable bracket.


Ignition module and spark plug wire installed.


I moved the pivot point for the intake slide closer to the center of the cam. There was a lot of extra movement of the slide that wasn't necessary.


Well we are getting down to the short rows now and not much left to do.
Carburetor, throttle, gas tank, and associated parts left then to fire it up.


Thanks for looking
Ray

 

[TonyM]

Out of curiosity, Does your valve open on the pull stroke of the link rod or the push stroke. The cam rotation looks like reverse of original, I am assuming Clockwise engine rotation viewed from above.

 

[Rdean33422]

Tony
My slide valve opens with the push stroke of the cam.
Yes the cam rotates in the opposite direction of the original engine with the large cam gear on the right side of the drive gear instead of on the left side. You may have also noticed that the original engine's drive belt had a half twist in it to reverse the rotation direction of the drive belt and enable the car to move forward.
Thanks for the comment
Ray

 

[Rdean33422]

Modified and installed the carburetor and added a throttle.


Fuel tank next.

Thanks for looking
Ray

 

[Rdean33422]

Working on the fuel tank.
These are the bits that make up the tank.


Installed view with an aluminum riser.


And from the front.


This carb uses a remote needle valve and the engine idle mixture is adjusted by varying the amount of bleed air instead of the amount of fuel supplied. This is the second carb of this type that I have used on my model engines and I still need to get more familiar with it's adjustments.

Thanks for looking
Ray

 

[Rdean33422]

This is what we have been waiting for.


This short video shows the engine running at about 650 rpms but I would like it to be around 300. There are several things that need attention before I am satisfied with the build. The slide valve is one issue as I am losing about 25% of my power stroke around the valve. That also affects the intake stroke as it sucks some air in around the slide.
This build is not complete and I will post another video when I am happy with it.

Thanks for looking
Ray

 

[gbritnell]

Great job! It looks and runs nicely!

 

[lee webster]

That sounds as good as it looks!

 

[Rdean33422]

Thank you both for the kind words.
Ray

 

[roughcaster]

Thank you both for the kind words.
Ray

well done

 

[Basil]

Well done! Such a cool engine design. The essence of simplicity and beauty. Thanks for sharing

 

[Rdean33422]

Thanks Basil


Worked on the slide valve some more today and came to the conclusion that it was always going to be a weak point of the engine. The use of springs, even stiff ones, to press the slide valve against the intake housing when the engine fires just isn't going to work. If the slide is lifted even a few thousands the power cycle and or the compression cycles are greatly reduced.
I tried using nylock nuts to achieve a preload on the slide with out any springs and as that did work as shown in the last post it was not something I was happy with.
This is my solution.
I cut a recess for an o-ring in the outer and inner plates for the slide to ride against sealing both sides of the slide at once. I used the nylock nuts but now I don't have to tighten them down as much which allows the slide move easier.





After a couple of test runs it seems to have solved the leaking problem.
When I test run the engine now there is a noticeable difference in the output power so much so that I have to bolt it to the bench so it doesn't run away. It also starts much easier now.
I have a couple of other things I want to do to it and then a completed project video.

Thanks for looking
Ray

 

[Rdean33422]

I made some changes to the engine, mainly cosmetic, and shot the final video.


1" piston
2" stroke
8" flywheel
water cooled
181 degrees highest recorded temp at cylinder head
156 degrees water temp in tank
roller bearing on the connecting rod
350 slowest rpm recorded
600 rpm is where the engine likes to idle
Over 5 thousand views.

Thank you one and all for following along with likes and comments it does make a difference.
Ray

 

[minh-thanh]

Nice engine and runs great
Congratulations !
Thanks for sharing.
And the next project will be...??

 

[TonyM]

I made some changes to the engine, mainly cosmetic, and shot the final video.


1" piston
2" stroke
8" flywheel
water cooled
181 degrees highest recorded temp at cylinder head
156 degrees water temp in tank
roller bearing on the connecting rod
350 slowest rpm recorded
600 rpm is where the engine likes to idle
Over 5 thousand views.

Thank you one and all for following along with likes and comments it does make a difference.
Ray

That's one of the best running benz engines I have heard. Can you tell us what compression ratio you used and what you set your inlet timing at.

 

[Jasonb]

Running very nicely particularly when at the slower speed.

I wonder is swapping out the aluminium belt pulley for a steel or iron one would add a bit more flywheel effect to help with slower running?

 

[Rdean33422]

And the next project will be...??

That's a very good question have any suggestions?

That's one of the best running benz engines I have heard. Can you tell us what compression ratio you used and what you set your inlet timing at.

The compression ratio is close to 4 to 1. The inlet timing opens a little before TDC and closes a little after BDC.
The slide valve arrangement does not lend itself easily to valve duration or timing changes. There is a very narrow window where the engine runs or doesn't run.

I wonder is swapping out the aluminium belt pulley for a steel or iron one would add a bit more flywheel effect to help with slower running?

The belt pulley would have to be considerably heavier to have much effect as it is mounted on the cam shaft that rotates a half the engine RPM.

Thanks for the comments
Ray