Well, I spent a few minutes tweaking the motor today. No new parts, just a timing wheel made from a 360 deg protractor.
Here are some videos:
The Engine running about 2500 RPM. Being as there is no real throttle to control RPM, you control it through mixture. Richer runs cooler and slower, lean runs hotter and faster. One issue with the vapor carb is that this is a moving target as the powerful hydrocarbons vaporize first and so you have to add a ton of air, then what is left is less volatile and you have to adjust it with less air bypass to enrich the mixture.
I used a smaller and lighter flywheel (5 inches) than the plans called for because this is about all my 7x12 can turn. Maybe when the cam timing is better and the ignition more reliable, I can get it slower, but this is about it for now.
The old timing light I have pops ghost images, but the timing is pretty close to 10 degrees BTDC. I did not have the timing wheel when I shot this, so I will use it when I fine tune the ignition timing.
After 20 minutes and 2 tanks of Coleman fuel with a few drops of Marvel Mystery Oil, the cylinder only got up to 190 degrees and the head only up to 145. I do not see it being run much harder than this, so that is about my benchmark for temp. Then she ran out of gas....
The coil was mounted with the old bracket from when I had the coil mounted fixed to the Webster base. If it becomes a permanent part, I will make a more elegant mounting system. Timing is changed by rotating the position of the flywheel and the new 1/4-20 setscrews hold it very well. Right now it HAS to be clamped tight to the table because the flywheel is way out of balance from the addition of the magnets. I might epoxy some washers 180 degrees to balance it.
The Vapor tank is a transplant from the Webster. It ran good, so I just wanted as few variables as possible to get it running smooth. The tank for this engine will be made when my rotary table arrives.
The intake valve seem to be floating a bit causing it to stay open and blow fuel out of the tank. I later deduced was exhaust timing closing too early and creating pressure in the cylinder, then the intake opened and the pressure went into the tank, spewing fuel. But, I had some stronger springs, so I put them on just to make sure. The other ones seemed a bit week.
The Marvel mystery oil does not burn so it just collects in the cylinder. This is a good thing. Once it is broken in I will reduce the mixture as even now it does not smoke when running. The smoke you see in the videos is from 3and1 oil used to lube the valves and cams.
There is a little burnt oil and carbon on the exhaust side as to be expected when it is so oil rich. This is after about an hour of running and 10 tanks.
Still on the fence when it comes to the piezo ignition. I might see if I can tuck this coil in under the cam in a tasteful way. I do not know if it will deliver a reliable spark at cam RPM, so it might have to stay on the flywheel. Maybe if I paint the lamination silver or something...
More to come...
