David Kerzel hit miss engine (sort of)

[Chris Hamel]

I have watched my friend Ray Dean build several engines so one day I decided to try and turn a crankshaft. It didn't come out perfect, but certainly usable. Since then with Ray as my backup I have continued to build on it. I am using the plans published by David Kerzel as my "inspiration." Since I was planning to use an o-ring on the piston, I made the cylinder liner out of aluminum . The flywheels were turned from some steel slugs I got at a salvage yard. When I go to install the weights and yoke for the governor I plan to just drill a couple of holes in the one flywheel. Ray cut the connecting rod for me the cnc mill. Both the rod journal and wrist pin journal are unbushed at this point. I ordered an electronic ignition from eBay which may take a few weeks since it is coming from China.

 

[Papa Charlie]

Nice work. Those hit and miss engines have been running a lot of equipment and appliances for many years on the farm well before there was electricity available to most.

 

[rogerl]

Chris:
After seeing Ray build the Royal Blue hit miss engine on this forum I decided to try to build the engine from David's plans as well. I redrew the parts in Solidworks and made some changes to the to fit my machining abilities. I have the design model complete and I am currently working on the detail drawings. After the drawings are done I am going to start my build. I am sure I will be asking Ray some questions during the build process. Good luck with your motor. I hope it runs.

Roger L

 

[rdean]

Chris your engine is coming along nicely and I was impressed to see some of the bits that give me trouble you made easily. I am sure it will be a good runner when you are finished.
Always willing to help when ever I can just ask.
Ray

 

[Chris Hamel]

So I took my engine and had Ray look it over. He convinced me to remake several of the valve train parts. Works much smoother now. I decided to see if I could make it run even though I still need to build the centrifugal governor. I rigged up a make-shift fuel tank filled it with fuel oil mix from my weed eater. For the ignition, I used a home made Hall sensor ignition system. I found the schematic online. After messing with it for about an hour I finally tried choking it until fuel ran out. After a few flips it started to pop. I managed to get it to run for close to ten seconds until it used up the fuel laying in the carb. I came to the conclusion that I am going to come up with a different design for the carb. ( back to Ray's to see how how he made his carb) I am really excited knowing it will run. Tomorrow I start on the governor.

 

[rdean]

Congratulations it is always a great feeling when it actually runs even if there is more to do.
Ray

 

[rogerl]

Chris:
How are you going to make the ends for little arms that go into the bobbin that slides on the shaft? I looked at the ones from David Kerzel and the round ends looked very difficult to machine, at least for me. I redesigned the arms to have 1/16" pins inserted and 1/8" brass balls soldered to them. The brass balls would run in the bobbin. I am out of town so I can not send a screen shot of the model. From looking at the photos from Ray's engine it looks like he has a different design as well.
I have not done anything with drawing the carburetor. Maybe Ran can post some sketches of what he built.

Thanks
Roger L

 

[Chris Hamel]

Talked with Ray. He said he didn't make the little round ends, just shaped the arms enough to make it work. He suggested that when I turn the bobbin that on the side of the groove that faces away from the flywheel, I cut it at a taper instead of straight in. This allows clearance for the arms that tilt when the weight expands.

When i pressed the yoke on to the hub I gave one too many pumps and it cracked. I'll probably remake the yoke today.

 

[Papa Charlie]

Very cool project. A lot to take into account.

 

[Chris Hamel]

Worked on the centrifugal governor today. Had to remake the yoke since I cracked the first one pressing it on to the hub. The picture below is the cracked one, but I wanted to show that the design is different from the plans. Ray came up with this design and it is fairly easy to make with a lathe and a mill.

I didn't even try to make the arms the way they show on the plans. I started with the basic shape and used my die to touch them up to where they would function. Pictures below show the completed assembly. I still have make the arm that latches with cam follower.