Piston Valve Engine - How to Reverse?

Look up Stephenson's link

A simple piston valve engine with no lap or lead can be reversed by swapping over the inlet and exhaust. A changeover valve can be made to do this. This doesn't need any change to the engine itself, just a valve with four ports. In one position A goes to B and C goes to D. In the other position, A goes to D and C goes to B.

You can't reverse a slide valve engine in this way because the valve would lift off the valve face when steam is applied to the inside.

Steering engines for ships used to use this idea.

John

If you do have some lead on the valve then the engine will run in one direction and that can be changed by the eccentric in the same way you would a normal slide valve engine be that with a simple slip eccentric or one of the other reversing gears such as the above mentioned Stephensons

Simplest way to reverse is as Jason said is with a slip eccentric this Grasshopper Engine I built has a piston valve and slip eccentric if you send me a PM with your email address I'll send you the plans.

Stew

Edited By Stewart Hart on 13/04/2017 07:33:33

Edited By Stewart Hart on 13/04/2017 07:34:07

Most Wilesco engines use a slip eccentric.

The Maxitrak Allchin uses Stephenson's linkage on a piston valve engine.

If you want a reverser valve (i.e. it swaps the inlet and exhaust) go read "Making Simple Model Steam Engines" by Stan Bray.

Edited By James Alford on 13/04/2017 17:07:22

Resurrecting a old thread of mine: I have been working on other things, but now am thinking about this engine again.

I have sketched out the attached plan, taking the dimensions and general layout from information on the internet. Whether they are good or not is another matter.

Have I understood it correctly that if I simply use a reversing valve to put steam in the pipes currently labelled "Ex", using the current "In" as the exhaust, the engine will run in reverse? The plan is to make this a twin cylinder, so it should be self-starting.

Regards,

James.

HI JAMES, A little late on the scene But for what its worthI have been constructing J P Bertinant's "Marcher" twin marine steam , engine Now the drwgs &casting set ( Messers Reeve' s Birmingham ) Come compleate with castings for either piston or slide valve operation inc castings for the reverser block (available seperatly) I opted for the piston valve as somewhat simpler inc the reverser block when using this set up engineis known as inside outside admission !!! confused you should be !! Regards PAUL S

Edited By Paul Smitherman 2 on 22/02/2022 16:07:28