Converting single acting to double acting

[nigel jones 5Participant @nigeljones5]

I have a Vee twin single acting oscillating steam engine which I would like to make double acting. The cylinder pivots on its mid point. Is it as simple as duplicating the existing inlet/outlet holes as a mirror image or is there more to it (I will ensure the con rod end is steam tight). Thanks.

[nigel jones 5Participant @nigeljones5]

[JasonBModerator @jasonb]

That's basically all you need to do is have an extra hole and passage to the opposite end of the cylinder and another pair on the pivot. The fun part is drilling the passage sin the pivot to link the pairs of holes.

[nigel jones 5Participant @nigeljones5]

Thanks Jason – ive not tried running it yet but it struck me that it had been designed to run double acting but then had been plumbed in wrong – please take a look at the photo and you will see what I mean?

[JasonBModerator @jasonb]

That does look like a double. You can just see the tops of the plugs where they cross drilled to join the ports.

Plumbing looks OK. If we said the open brass union on the right of the photo was the inlet then that is plumbed to the inlet on the left cylinder. The blanked off one on the right cylinder would be the exhaust and is plumbed to the other exhaust hidden behind the flywheel and the taken away by the open ended pipe.

Would get rid of that aluminium flywheel for a start.

[JasonBModerator @jasonb]

I think that is the Blackgates one you have there.

If you look at this one the two inlets are plumbed together as are the two exhausts

Only difference to yours is that uses the holes at the side for inlet and exhaust as per drawings but yours has not had these drilled but instead has a hole from the back of the port face into each of the long linking cross drillings.

If you want to get really fancy then the pipes can be taken into a manifold and a switchover valve built so you can change direction by feeding steam into the exhaust and out the inlet which is handy if used in a boat. As this very nice restoration by Ramon shows

Edited By JasonB on 30/04/2018 20:44:58

[nigel jones 5Participant @nigeljones5]

Thanks JB – good news indeed. Its a bit rough so I will strip and machine if needed. Any idea where I can get a drawing of the reversing block?

[JasonBModerator @jasonb]

You could message Ramon on her, he does not post that much but should get the message notification, more of that engine in this thread

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