- Joined
- Feb 17, 2008
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This was kind of a trip down memory lane for me. I built a Poppin 26 years ago. It ran, but not well. I live just shy of 6000 feet elevation and the reduced air pressure here makes flame lickers a little more of a challenge. This one runs well. I have learned a few things over the years. I have about an hour of running time on the engine after getting it adjusted. Mostly in 5 to 10 minute runs.
The crankshaft and valve shaft both run in ball bearings and the cam follower is also a ball bearing. The standard is built up from 4 parts bolted together with 2-56 screws. Makes life much easier. The cylinder head is cast iron as I plan to try a sliding valve on it instead of the leaf valve. Note that this one is version 1. Version 2 will have the slide valve. I machined all the common parts at the same time so there will only be a few new parts to make for the second engine. The base plate had increased in thickness from 1/8 to 1/4 thickness to allow a little taller alcohol burner with out having to step the still unmade wooden base plate. The burner still has to be made. I have been using an old one for testing.
I have the oil cup for the engine, but although it could be functional if installed, any oil in the cylinder will increase the drag enough to keep the engine from running. The biggest problem about running the cylinder/piston with out lubrication is water. Cast iron likes to rust. I set the rotation up so withe the crankpin down the valve is open. The engine is free enough that the weights of the crankpin, big end and connecting rod will rotate to the down position when standing if the engine is stopped with the crankpin any where more than 30 degrees or so off the top position. This allows the cylinder to dry out after a run. Alcohol flames have quite a bit of moisture in them so some water vapor collects in the cylinder. After running, turn the engine over a few times to bring fresh air in to help displace it. Of course if you live where there is high humidity that may not help much. 15 percent humidity is high here if it is not raining, and that only happens a few times a year.
Gail in NM,USA
