Beam engine build

[Johnjo]

Hello everyone, I am fairly new to this forum and new to model engineering in general. As a first project I decided to make Brian's version of the Elmer beam engine. I have almost completed machining all the parts, just a bit of work to do on the base and some silver soldering and then I'm ready for assembly. Now here's where I need a bit of advice. Having never built anything like this before can someone explain in simple terms about the setup and timing of the engine. For example what position should the crank and con rod be in in relation to the throw of the eccentric rod. Any advice would be much appreciated.

 

[lathe nut]

Johnjo, can't help you there but there are great mechinical minds in this group that will help, I call them "the well spring of wisdom" glad of your build, hope you took photo's as you went and post them and a post of it running, glad for you, Joe​

 

[Richard Carlstedt]

John I just found your post, so this is a bit late I am afraid, but to answer your question on a simple
steam engine with a D valve , that is no lap or lead , the maximum eccentric throw is always 90 before the max crank throw point
AND the eccentric max point leads the crank shaft in that direct.
So if the crank is at 6 O'clock and the eccentric is at 9 O'clock the engine will run Clockwise and if the eccentric is at 3 O'clock
it will run CCW.
Rich

 

[Jasonb]

You will find that most engines run better particularly if using steam with some lead, I typically use 30degrees as a starting point and adjust from there. So that means you need the max throw of the eccentric to be 90deg + 30deg = 120Degrees from the crank pin. So with crank pin at 12Oclock max eccenytric throw is a 4o'clock for one direction or 8o'clock for the opposite direction.

Be aware that a lot of beam engines use a bell crank of some sort to get the horizontal movement of the eccentric rod to the vertical direction of the valve so that can reverse the direction it will run in from what Rich says above.