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Dario Brisighella      Oak Creek, WI


This is the largest of the model Hit-or-Miss Engines in my expanding stable of small engines. The bore is 1.625” and the stroke is 2.000”. The casting kit is from Rocky’s Model Engines. Rocky himself is ready and willing to assist the builder(s), should there be a need. The castings are nicely done and dose not require a lot of effort to smooth out if you’re not a purest. I’m not that much of a purest. It must be obvious that I am far from one and it shows in Photo #1. While most R&V Engines were painted Green, I tired of plain Green and Red Engines and went overboard with the rich Blue which stands out nicely with the bright polished Brass and Bronze.

The casting kit is offered with either cast iron or brass flywheel. I opted for the brass version as they offer a bit more weight and, besides they look better when polished. The model is designed for a more regular igniter system, but as most all my engines I adapted the Hall-Effect Ignition system from MJN Fabrication. I like the advantages of being able to easily change the spark timing. The adjusting leaver can be seen in Photo #3, next to the outboard flywheel. The ignition module can be see in Photo #6. The 6 VDC Gell-Cell battery is hidden between the Cherry wood rails.

While the engine runs well and it is quite easy to keep the RPM’s low, the engine is rather noisy. The governor weight on the flywheel does make contact with the exhaust valve latching assembly on every revolution. See Photo #2. Adding rubber blocks to the flywheel where the governor weight makes contact does help quiet things down a bit.

I’ve made several changes to the engine and they include; Rather than a conventional piston ring, I am running a regular O-Ring in its place. While the drawings call for split babbit main bearings as the driving gear was to be press-fitted to the crankshaft, I elected to use more convent one-piece brass bearings and keyed the small gear instead (makes things easier to take apart later on).

The robust crankshaft (.500”), is of the silver-brazed design. Several fellow modelers have asked about the finish on the steel driven timing gear and the steel side rod. This can be best see in Photos #1 & #3. The finish is called “Damasking”, and it’s a simple finish to apply. Simply use a drill press or milling machine, a hardwood dowel and some valve-grinding compound. The circles created are overlapped about forty-percent in both the “X” and “Y” direction. The milling machine works best as one can use the micrometer dials to keep the spacing even.

I like to see these engines turning over slowly and I do keep shaving down the piston head to lower the compression which in turn lowers the engine speed. I do wait until the engine is broken-in before I tinker with the compression ratio though. The large heavy brass flywheels sure helps the coasting phase between the firing cycles......



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