Valve Stem Guides
The valve stem guides, one on each side of the engine, keep the valves properly lined up on the steam ports as the “monkey motion” goes up and down.
I started machining the guides by squaring up two blocks of steel.
Next, the valve guide channels were milled.
Then the sides were milled away and flange holes drilled.
The valve stem crossheads were machined from bronze.
Brass valve guide retainers to hold the crossheads in place.
Then I turned and machined the link block washers that mount to the valve stem crossheads.
One of two complete valve guide contraptions waiting to be installed on the engine.
Valve guide assembly mounted to the main crosshead guide.
D-Valves
The D-valves are used to divert incoming high-pressure steam to the top and bottom of each cylinder via ports in the steam chests. They are actuated through a complex pushrod system driven by eccentrics on the crankshaft.
The D-valves were born of this chunk of squared-up brass.
I machined the valve stem keeper slots for both valves on one side and then flipped the block to machine the “D” shaped recesses on the valve face, leaving enough material between them for the separation cut and finish mill.
After splitting the two valves apart.
D-valves, stainless steel valve stems and valve stem keepers.
D-valve assembly installed in the steam chest and connected to the valve stem guide.
It looks like you are building an engine similar to the one I built and got running in 2018 (Mich-Cal #2 by Bill Harris). I started mine in the late 1990’s before any castings were available. You definitely have an advantage there. I back dated mine to look like 1880ish. You can see it run here: https://youtu.be/HplDwhcpULI
Mine runs on propane and is a lot of fun. Thank you for liking the silver brazing ost I put on my blog recently. Tim Guenther
Beautiful Shay, Tim! That looks like a great runner. Great camera shots, too. I especially enjoyed the cold-weather plumes – something we don’t experience much of down here in Florida!