My Ordinary Little Hit & Miss Engine

[Myrickman]

A most excellent little engine Rudy! Picked up a lot of good tips on your build. Will be that much sweeter when you get the governer installed. Paul

[Dave Otto]

Very nice Rudy!

Fun to see something come together so quickly; unlike my projects which seem to go on for years.

Dave

[Don1966]

Awesome results Rudy she's quiet a runner................ 

 
Don

[b.lindsey]

Most impressive Rudy. Quiet and very smooth too. Looking forward to seeing it in hit and miss mode. Well done!!!

Bill

[cfellows]

Excellent!  Good looking and a great runner.

Chuck

[fumopuc]

Hi Rudy, it is running like hell. Waiting for the govenor. Well done.

[Roger B]

Excellent    That's running a few 1000 rpm 

[Jo]

  Nice.

Jo

[sbwhart]

Great Stuff   

Well done

Stew

[rudydubya]

Everyone, thank you all for your kind remarks.  I'll try to hurry and get to the finish.

But first, the hit & miss governor.  The governor is a common centrifugal hit & miss type with a sliding bobbin (in red), a lockout lever (green), and a fixed stopblock (blue) on the pushrod (orange).  A small torsion spring (black) made from 0.010" music wire helps clear the lever from the stopblock.  The lever blade is arched up and away from the lever body to clear the cam gear screw and reach the bobbin.

The governor weights (orange) are attached to arms (blue) that pivot on a carrier (green) attached to the flywheel.  The governor springs (yellow) are hooked over screws in the weights.

The most interesting part may be the lever.  It's made from a single piece of brass with a short length of 1/16" brass rod Loctited in as a spring stop.

I made it with the aid of some fixtures to hold it for the curves and pockets.

Here is the lever after I had smoothed it with a file and secured the pin with Loctite...

Continued...

Rudy

[rudydubya]

Continuing with the governor parts, here's the combined lever mount/pivot and pushrod guide.  To keep the lever short, I put the mount closer to the cam and removed the original guide.  The holes for the old guide are are still there in the frame, and I thought about using the holes to mount some kind of lockout switch for the ignition while the engine was coasting, but the thought faded.  I don't mind a few wasted sparks.

The governor-weight pivot arms, made from brass ...

And then the pivot carrier, made from aluminum.  After it was made, I set up the flywheel on my rotary table to drill mounting holes for it.

After I had drilled for the carrier, I took the opportunity to clean up some of the scars on the flywheel spokes.  I think next time I'll do the flywheel webs on the mill and rotary table instead of the lathe.

The governor weights are 3/16" diameter brass, 1/4" long and drilled and tapped through for 0-80 studs and screws.

The pushrod stopblock is just a piece of 3/16" diameter brass drilled through for the pushrod, with a tapped hole through one side for a 0-80 setscrew.

The governor springs are 0.010" music wire close-wound on a 3/32" mandrel (I made them about 0.70" long, but had to shorten them to fit between the weights).

And everything put together on the flywheel.

Continued...

Rudy

[rudydubya]

A few more additions before I get to the good part.

While I was testing the engine with the governor, I found that I didn't have enough adjustment range to set the carburetor properly for good hit & miss operation.  I made a simple replacement carburetor using a tapered 0-80 screw for a needle.

I threaded a piece of brass rod and screwed a long 0-80 screw through it.  I turned the taper on the screw with very light cuts while running the lathe backwards.  The threaded needle also allowed me to use internal threads on the carburetor body, easier to make than my previous version.

Also new is a finished base and ignition box for the engine.  The engine and base top can be lifted off as a unit to access the ignition module and batteries.  The plug wire and ground are routed from inside the box through notches to the knurled connectors outside.  The Hall sensor connectors are tucked inside the box when it's closed.

The finished product.  I haven't decided if I'll paint it or not.

I'll post a video of it running in hit & miss mode next post.

Rudy

[rudydubya]

And here it is running in hit & miss mode.  Hope you enjoy it.

[youtube1]https://youtu.be/obseeCEDECU[/youtube1]

Thanks all for following along.

Regards,
Rudy

[fumopuc]

Hi Rudy, excellent. A very smooth runner. I enjoy it to follow the motion.

[10KPete]

That is a most amazing little engine Rudy. Those little, tiny, parts are way beyond me I think.
And it runs so much like the full size engines!!

Pete