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Side Valve i.c. engine from Bar stock

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Brian Rupnow:
That went well!! The machining was pretty straightforward stuff. I did learn one new thing today. When you order this type of bearing, the outer diameter comes in at .0005" to .001" oversize so that they can be pressed into a hole made by a standard reamer. For 49 years now I have been putting a note on machining drawings "Bore for light press fit of .562" nominal o.d. bearing (or bushing).--I never actually realized that there wasn't some magic formulae or set of undersized reamers involved to do this. As you can see in the picture, the 1/4"small end bearing is sealed with rubber seal lips. I was unable to buy a sealed 3/8" i.d. needle bearing----anywhere, for the big end. I guess this means that I will be running some oil in the crankcase after all.

Brian Rupnow:
By Golly, Miss Molly---I must be doing something right!!! Along with all the other things I had to do this weekend, I managed to carve out enough time to make the con rod AND the ignition points mounting block. I decided at the last minute not to put the raised boss on that is shown on the drawing. The head of the bushing it clamps to only extends 3/8" past the aluminum backplate, so that is the thickness I finished the points mounting block at. I used a scrap of bronze, just to balance the bronze flywheel aesthetically. The points mount up perfectly, and all it need there now is an ignition cam to finish that bit off. The #5 capscrew sticking out horizontally is where the handle will screw into, to adjust the timing.

Brian Rupnow:
Time for one last "Quicky" before I shut down for the day. The all important ignition cam. This cam serves a dual role in life. It opens/closes the ignition points, but also acts as a shaft collar to prevent any axial movement of the driven crankshaft in its bushings. :ddb:

Brian Rupnow:
The ignition cam is machined and installed. For any newbees following these posts, this kind of ignition cam holds the points open most of the time. They only close when the flat, which is about 3/8" long pass under the rubbing block on the ignition points. This gives enough time to charge the primary windings on the ignition coil, and when the points open again as the cam revolves, that is when the spark occurs.---Brian

Brian Rupnow:
The cast iron cylinder and the aluminum valve body (which I have been mistakenly calling the combustion chamber) are now permanently and forever locked together with a ring of super duper heat resistant gasket material and some high temperature gasket goo.--That's not to say I couldn't take them apart, but I don't want to. I want to treat the two items as a single component now, hone them together, lap them together, and then make my piston to suit the bore.

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