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Peter Wood,          Rolling Hills Estates CA


Hit ‘N Miss farm type engine    6/2/2007


It has been quite a while since I last submitted my Stuart steam engine and my unfinished Economy engine built from Joe Tochtrop castings. This new engine is my own design started in January 2007 and first run this week.

Here are the specs:-

Ř  Single cylinder, horizontal Hit ‘N Miss farm type engine.

Ř  1.13in bore x 1.75in stroke.

Ř  Swept volume 28.5cc.

Ř  Electronic ignition with Hall sensor and rare earth magnet.

Ř  Electronic speed control with solenoid control of exhaust valve.

Ř  Built entirely on my 6in atlas lathe with the exception some milling of the main chassis done on my friend’s milling machine.

Ř  No castings were used. Flywheels weigh 2 ˝ lb each and are 4in diam x 1in wide.

Ř  Piston has 2 rings from Coles Models.

Ř  Chassis is cut from 4in x 2in rectangular steel pipe.

Ř  Fuel tank is integral in chassis.


I have taken photos during the construction.  The finished engine appears near the end of this document.



Figure 1. Rectangular steel tube mounted on cross slide. Cylinder mounting surface shown.




Figure 2. Fly cutter mounted in 3 jaw.




Figure 3. The cylinder made from seamless 1 1/4 in x 1 1/8in drawn steel tube. Flanges 1/4in CRS.


Figure 4. Flywheel blanks 4in x 1 1/8in hot formed steel pipe.



Figure 5. Boring the bearing housing holes using home made boring bar with 1/8in diam HSS cutter.




Figure 6. Counter boring the bearing housings before splitting them prior to silver brazing to chassis.



Figure 7. Slitting the bearing housings prior to silver brazing the halves to the chassis


Figure 8. The bearing housings set up for silver brazing.



Figure 9. Oxy-acetylene silver brazing bearing housings.



Figure 10. Initial turning of con-rod after big end was split and reassembled with 6-32 cap screws.



Figure 11. Con-rod almost finished. Note big end oil way and 2-52 pinch bolt for wrist pin.



Figure 12. Finished flywheels with web and hubs silver brazed. Note split hub and pinch bolt mount.



Figure 13. Roughed out CRS crankshaft with center drilled holes for turning between centers.



Figure 14. Rough turning the crank pin.



Figure 15. finish turning the crank shaft.



Figure 16. Crank shaft finished except for key slots.



Figure 17. Assembly of parts built so far



Figure 18. The completed engine.



Figure 19. Cylinder head detail



Figure 20. Front view.



Figure 21. Timing side view.



Figure 22. Top view showing timing gears, cam follower, push rod and rocker assembly.



Figure 23.  Ignition and speed control detail showing Hall sensor, rare earth magnet on cam gear and exhaust valve control solenoid.



Figure 24. The exhaust valve is held open when the solenoid is energized.



Figure 25. The roller cam follower is held away from the cam to slow the engine.


This engine has been both challenging and rewarding. It took me about 5 months of spare time to finish it during which time my 6 inch lathe handled some quite “innovative” set ups! When first run, it was obvious that the exhaust cam dwell angle was too long and resulted in the water jacket boiling vigorously and the engine having a “sporty” exhaust note. I reduced the dwell to open at BDC and close about 5° ATDC (crankshaft), it is much cooler and tamer now.

Before and during construction, I made a complete set of drawings using Microsoft Visio. I can supply these for a nominal fee to cover postage etc. if anyone is interested.






What’s in the video:


I designed the “Farm Type Hit ’N Miss Engine” engine to be built from standard metal shapes without the use of any castings. It can be built by anyone skilled in basic machining and brazing and having access to a 6 inch or larger lathe. The engine uses Hall sensors and an electronic circuit to provide timing and speed control.

The video shows the engine mounted to a wooden block in my workshop. The fuel tank is integral to the base and holds about 2 ounces of white gas (Coleman fuel) mixed with 5% WD40. A full tank lasts over an hour at slow speed. The hopper cooling water reaches only 140°F with the engine running unloaded.

The engine has a solenoid that holds the exhaust valve open via a lever engaging a stop on the valve push rod when the engine over speeds. When the speed drops, the solenoid releases and the engine fires normally and speeds up again. The speed setting is adjusted by a potentiometer as shown.


Click Here for details, description and schematic for the adjustable engine control module

A video of the engine running with the electronic speed regulator       VIDEO 1 (Windows media file). 




Well, that’s about it for now, please let me know if you would like more info such as electronic circuits, where I bought some parts etc.


Best Regards,


Pete Wood.

Rolling Hills Estates CA