Month: July 2016

SAM Hit ‘n Miss Ep. 7

To continue the story of the SAM twins, we have to fast forward to my next visit to Switzerland, which was a little over a year later. The project remained more or less idle, as it was back to reality for the both of us. My brother did finished a few parts, like the crankcase pressure regulator and the fill plug.

I regularly received an update, saying the engines are doing well and running. The engines got some running time for break in and to give them a good shake down…

The wood boards for the engines were made by our dad, as he is the wood worker in the family. The box for the battery, I picked up at the local crafts store.

Another addition to the engines was an oil level sight glass.

Here, the two finished engines running next to each other for one last time, I was taking one of them home with me.

SAM53 (800x600)SAM54 (719x800)

The engine, as it is today in my shop. I occasionally take the engine out and let it run for a while. Every time I run the engine, it brings back the memories of the great time I had together with my brother in his shop.

SAM55 (800x533)SAM56 (800x532)

This concludes the SAM project. It was a very special project for both of us. We are  contemplating doing something similar again, as we had so much fun…


Thank you for visiting my shop.

If you have any questions about SAM or any of the other projects, please leave a comment below, or email me at yogisworkshop(at)

For other projects from the shop, please check out the projects page in the top menu.



SAM Hit ‘n Miss Ep. 6

Now we know we have two running engines, and continue the work on the hit and miss governor and some of the finishing touches.

The “trademark” 5 holes were added to the flywheels.

SAM45 (800x611)SAM46 (800x600)

Here a picture of our test set up on the bench, with the two engine side by side, and the finished flywheels installed.

SAM47 (800x599)

The last major part we needed to make, was the hit and miss governor.

This was quite time consuming, as the governor is made up of a number of parts, all rather intricate. Unfortunately we didn’t take pictures while making the parts, so we will jump right ahead to the finished governor.

SAM48 (685x800)SAM49 (800x598)SAM50 (665x800)

…and the hit ‘n miss governor in action:


The 10 days where up, and my visit was coming to an end. There were still a few little things left to do, but they will have to wait for another time.

When we started, we really didn’t know how far this project would go, especially in the time frame we set ourselves. Having two complete, running engines was amazing.

My brother, and yours truly posing with SAM for a photo.


In the next episode, we’ll finish the story and complete the last few bits and pieces.


Thank you for visiting.

If you have any questions, please feel free to leave a comment and I’ll get back to you.




SAM Hit ‘n Miss Ep. 5

We are getting really close to see if there is life in these engines. The last thing needed before a test run, is the valve train. These parts are very time consuming, requiring a number of different set ups.

SAM38 (800x599)SAM39 (800x601)

No CNC equipment in my brothers shop (at the time of this build. He has since added some new equipment to his shop). To make the radius on the parts, we used a fixture to hold it in the dividing head.

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The (almost) finished parts…

SAM41 (800x599)

…as the rocker arms needed the radii added.

SAM42 (800x600)SAM43 (800x599)

Now we have everything together, and are ready to give it whirl.

SAM44 (800x599)

And lo and behold, the engine fired right up on the very fist try!


We where prepared to spend some time adjusting and tinkering, as on some of our previous engine builds, a considerable amount of fiddling was required to get them running. No need on this one, it ran beautifully.

This was our first internal combustion engine we built. The excitement was enormous.

This was at the end of day 8 of the project. Now we have two more days to finish the hit and miss governor and put the finishing touches on to the engines.


Thank you for visiting.

For other project from my shop, see the projects page in the top menu.

If you have any questions, please feel free to leave a comment and I’ll get back to you.


SAM Hit ‘n Miss Ep. 4

We continued to make parts, steadily getting closer to completing the engines. By now, we were on day 5 of our venture, and half way trough my short stay. Things were looking good and we felt confident to finish the engines before I had to leave.

Both of the crank case covers, front and rear, are finished.

SAM31 (800x600)

…so are the valves and valve guides.

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The crank case feet are being finished.

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And an other shot of the current state of the project. They are starting to look more and more like engines…

SAM35 (800x600)

The cylinder heads are mounted, and the engines are fixed to a temporary board in preparation for the first test run.

SAM36 (800x600)SAM37 (800x601)

It wasn’t just my brother and I spending all our time in the shop. We had time for the family too. Here I’m getting some help from my nice and god-daughter Karin. Lots of deburring to do…

SAM Helper (600x800)


Thank you for visiting the shop.

If you have any questions, please feel free to leave a comment and I’ll get back to you.


SAM Hit ‘n Miss Ep. 3

The cylinder head is one of the more complex parts of the engine. It required a number of set ups in the milling machine, using a dividing head.

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The crankshaft is next. It is built up from individual parts. To insure a true running crankshaft, we machined the crank webs as pairs. Here, the holes for the crank pin are machined, using a boring head.

SAM23 (800x557)

The crankshaft finished assembled:

SAM24 (800x600)SAM25 (800x598)

The connecting rods being machined:

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Here a shot of the two rods, almost finished. The only thing missing are the chamfers on the big end, which are needed to clear the crank case.

SAM27 (800x600)

The bronze split bearings being turned.

SAM28 (800x601)SAM29 (800x600)

The finished rod, piston and cylinder.

SAM30 (800x600)

The pistons are made to a very close fit to the cylinder. The piston is about 0.01 mm under size, which allows it to move free, but is still air tight. The groove in the piston is intended as an oil retention groove. No piston rings on this engine.

In the two short videos below, we are demonstrating the fit of the piston in the cylinder. Holding one end of the cylinder closed against the palm of the hand, the trapped air makes the piston spring back until it is released, allowing the piston to fall free.

We are making good progress, and will continue in the next episode.


Thank you for visiting my shop.

If you have any questions, feel free to leave a comment and I’ll get back to you.