Valve travel
Valve lap ( steam lap and exhaust lap if there is any exhaust lap)
Valve lead at top and bottom dead center (This with the steam lap will give us the angle of advance. The lead is the amount the steam port is open with the piston at dead center.
Take these numbers for ahead and astern....we will see if its even.
Width of the steam ports
Width of the exhaust port
Width of the bridges between the ports.
Do this on the HP and LP sides. Then we will know where we are anyway
It would be good to know what the volume of the reciever is.....filling it with water and then weighing the water is a good way to do that pretty accurately.
From this known point, we can start to think about the new gear and compare the motion/movement of the new gear to the old one. That way we will have an idea if we are getting better or worse as we design it.
A box link looks like a common bar link with two curved bars. The difference is the inside face of the bars has a machined groove that a bearing fits into. I have that on my engine and I did if for a reason. My engine runs about 600 rpm. There is no way in hell I can get an oil can spout on an oil hole in a moving link at that speed. With the bearing inside, capilary action wicks the oil in, and the enclosed form hangs on to it longer. I just squirt a little on the top side of the link and it goes right where I want it.
Its origins as I have been told were in our early steam navy on the Pinance and cutters.
It would appear the Engineers 3rd class where filing the link slots on conventional links longer trying to get better valve events and generally screwing up the engines.
This link is tamper proof....or at least tamper resistant.
It is a true pain in the backside to make accurately....it requires a fixture and a rotary table on the mill.....not for everyone.....but I like it.
Heres a sketch of the information I think we need to start with anyway.
Dave
...Not knowing that, the lead when the piston is at top dead center would allow me to calculated the angle of advance.
