Apology for so long in responding.
That is very nice work on your boiler, I must commend you for your ability and patience in soldering.
The pipe that is in your pic, if any water goes over the top it does not look like there is a way for it to return to the center drum and will assuredly exit through the piping. I don't think the threat of carry over is too much concern. As I wrote above, my friends boiler simply has a hole in the center in the upper head with a "T" welded to it and he has never mentioned carry over problem and he runs his car very often. He's never had any water damage to the engine. He's had many lower end issues, because he runs his system at 400 psi and the engine was really designed for 200 psi. He runs his steam bike at 800 psi, it sure makes that little "1/4 Horsepower" Charles Strelinger/PM research engine sing at about 1400 RPM, he has broken and repaired it many times. He built a new 3 cylinder engine using three of those engine kits. I think he got all three for 750 dollars at the Engineering modeling show NAMES show.
The valves I am using. This is for my Locomobile steam carriage, the steam plant is very simple and very basic. Only have the necessities. Feed pump and hand pump, throttle, and relief valve. The fitting out the bottom of the drum to the lower sight glass provides good accurate reading during operation. It acts a bit strange at fire up, rising very high and then subsiding and stabilizing. The sight glass is about 20" away and when I go around left corners, the water goes up and when I go around right turns the water goes down. The top fitting for the glass is connected to a line that I use as a "top blow", this is a valve for getting rid of excess water during fire up or if we forget to open the bypass and overfill with the feedpump while driving, all it takes is a pretty girl to get the valves clattering
, we usually fire up with the boiler completely full for about 20 seconds and then start valving it off. My Ofeldt only has about a gallon of water, but it will run about 1 or 2 miles with that volume.
I also use the top blow at shows, the car is so quiet with the muffler, I hear people talking when I drive past and I hear them say something like "oh that is an early electric car" and then I give a couple blasts with the top blow out the back to let them know that it's steam. They look very puzzled.
-Ron