The Craftmans Shop > Model Engineering
Side Valve i.c. engine from Bar stock
Brian Rupnow:
Now here is something a little different. I really didn't like the look of the exhaust pipe running out of the engine on an angle, and the carb being mounted on an angle, but I had to design it that way so the exhaust wouldn't interfere with the carburetor. Today I was down at Partsource, an automotive supply store, and seen a rack of steel 90 degree and 180 degree bend steel tubes for automatic transmission repairs. For a couple of bucks, I thought "Hey---If that worked out, I could run the exhaust straight out from the engine and mount the carburetor at 90 degrees." I can't bend anything on that sharp a radius without kinking it badly. That tube measures 3/8" o.d. and has a .028" thick wall. I will keep you posted on this and let you know if it works out.---Brian
Brian Rupnow:
For reasons far more complex than I want to go into (but mainly involving how little material was left beside the counterbored bolt holes), I have went to a total redesign of this part. I don't do this terribly often, but since it is almost the last major part, and because it will be made of brass now instead of bronze, I have redesigned it. I finished the last of my "drop in" engineering design contracts this morning, so hope to complete this part and possibly the fan tomorrow.
Brian Rupnow:
If the engine runs, I can guarantee that it will run cool. The white plastic fan is out of some computer hardware. I am not crazy about the color of it, (I may paint it) but at least the pitch on the blades is correct. I realize that the curvature of the blades would make it more efficient if it was going to turn counterclockwise, but it still puts out a good column of air if turned clockwise (I set all my engines up to turn clockwise.) That is because I use my variable speed drill as a starter, and if I run it counterclockwise the chuck loosens off. I still have to find some thin wall tubing of the correct diameter to solder onto my fan support to act as a fan shroud as per the 3D cad model seen at the early stages of this thread.--those little fans will really chop up fingers.
Brian Rupnow:
I think I may try my Chuck Fellows carburetor on this engine. It works great on the Webster. I will make a more complicated larger carburetor if I have to, but I already have the Chuck Fellows carb, and if I use it I can come straight out of the engine ports with both exhaust and carb and not have any interference.--Speaking of exhaust---I kind of like this. You can do nifty things with a piece of 1/2" diameter brass and a 1/16" slitting saw!!!---
Brian Rupnow:
Cross your fingers for me guys. It's pretty well all over but the final assembly. I am pleased with the way my intake and exhaust manifold turned out, and my Chuck Fellows carburetor looks real proud setting up there. Yes, I will be bevelling the corners on the tappet guide, gear backplate and fan support just like the solid model, but I thought I would wait until I had everything assembled and do it "in place". All I have left to fabricate is the fan shroud, and I MIGHT do that before I try to start the engine---but I am just as anxious to see this thing run as you are!!!---
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