Coles Corliss Steam - Need Help

[dsenechal57]

I have never set up a Corliss, but how hard can it be ?

My guess is as follows:

1. Figure out if you are trying to set the valves with the engine running over, as in the video above, and make sure you are not setting the valves for running under, which would have the flywheel rotate backwards from the video.

2. Remove the cylinder head from the end of the engine, and with a little air pressure turned on and fed into the top of the cylinder (using the normal feed point like in the video), rotate the flywheel to top dead center.
The upper valve near the cylinder head that you removed should start to admit steam either just before the piston reaches top dead center, at TDC, or slightly after TDC. If you don't hear air coming into the cylinder somewhere around TDC, adjust the gear so that that event happens (called setting the admission point).

3. Rotating the engine to bottom dead center (BDC), as you rotate towards bottom dead center, the upper valve near the flywheel should start to open somewhere just before, at, or just after BDC. Perhaps you can feel a pull on the flywheel when that valve begins to open.

4. A lower valve should start to open when the piston is about 70% down the stroke (check me on that) to release the cylinder pressure.

5. The upper valves can trip shut anywhere from 12% of stroke to some late amount of stroke, depending on how much cutoff you want.
I don't think the cutoff point is critical for an engine with no load, but when running on air, you may want a little later cutoff since air does not expand like steam.

Does this make sense?

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I followed your instructions. The steam valve starts admitting air very early, somewhere around 45 degrees before TDC. It can be tweaked a little with the front adjustments, but nothing close to that much. I wonder if the eccentric might be off. Those four page instructions talk a bit about the eccentric, but (to me at least) they seem backward (contrary to what I'm seeing and the overall drawing on the plans).

 

[dsenechal57]

I think this is one of the diagrams in question (not my diagram).

I would assume that the right side is where the cylinder head screws on.

Exhaust valves would be at the bottom, steam valves at the top.

I would say this is the same view as I posted above.

The sequence is that the upper right steam valve opens around TDC, and as the piston moves down its stroke, the exhaust valve on the lower left has to open to relieve the pressure on the bottom of the cylinder.

The upper right valve closes at some point during the downstroke.

When the piston reaches BDC, the lower left exhaust valve is closed, the upper right valve is closed, the upper left valve opens, and the lower right valve opens, pushing the piston back up to top dead center.



View attachment 150756

This leads me to wonder if there was, indeed, more than one version of the Coles Corliss. The engine in the video you posted is pretty much a mirror image of the one that I have. Mine has the cylinder assembly on the left, and the flywheel on the right. If that's the case, the above diagram makes sense for the one you posted, but not for mine. I wonder if the other three pages of the "addenda" are also for the engine you posted, rather than one like I have.

 

[dsenechal57]

This certainly IS conphuzing. Why would anyone make a drawing that has the front backwards reversed and upside down flipped over? If one were to put in the piston rod, then one would know what is forward and reverse.

I think that there may have been more than one version of the Coles engine. GreenTwin posted a video of a Corliss engine in this thread that is a mirror image of mine. On the engine in his video, these instructions make much more sense.

 

[GreenTwin]

This certainly IS conphuzing. Why would anyone make a drawing that has the front backwards reversed and upside down flipped over? If one were to put in the piston rod, then one would know what is forward and reverse.

The drawing is right-side-up as shown, piston rod is going from the piston towards the left (see the arrow).

Steam valves on top, exhaust valves on the bottom.

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[GreenTwin]

I think you will have to check the eccentric position first, then get the admission valves set.
You may have to loosen the grub screw on the admission valve arm, and rotate the arm on the valve shaft.

Make sure you don't introduce any slack (in-out) on the valve shaft if you loosen the grub screw that holds the arm to the shaft.

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[GreenTwin]

Did I post this link ?

https://www.homemodelenginemachinist.com/threads/corliss-steam-engine-coles-power-models.32152/

 

[GreenTwin]

This is Randall Marquis's Coles Corliss.
Randall drives steam locomotives.

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[GreenTwin]

Its almost like there were left handed and right handed casting kits.

Randall's photo is not mirrored, since you can read the coffee can.


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[Richard Hed]

The drawing is right-side-up as shown, piston rod is going from the piston towards the left (see the arrow).

Steam valves on top, exhaust valves on the bottom.

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Yes, I get that. However, what the OP says about the instructions, it all seems wrong. He sent the four pages which are extremely difficult to read but also use some term for TDC and TBC which are not standard. If the instructions are correct on the amount of degrees to place the valves, then that is good and would be correct for a Corliss whether it was right hand OR left hand as he says in his latest post.

The OP also has lookt at the eccentrics and wonders if they are correctly made or mounted.

 

[Richard Hed]

That's a beauty!

This is NOT a Coles/Ray Corliss. This is almost a mirror image but it is NOT exactly the same. It is a very fine Corliss but NOT a Coles.

 

[Richard Hed]

Thanks for replying to my query, Richard.

There's a 4-page addenda with timing instructions, and I believe I have followed it correctly. However, it was written in a very confusing manner that makes it possible I did not. For example, "Schematic Valve Setting Sketch, as viewed from the back side of cylinder ass'y toward the valve wrist plate ass'y". But the wrist plate ass'y is on the FRONT. It also refers to what the valves and linkages should look like when the engine is "at rest". I have no idea what "at rest" means.

Anyway, to answer your question, I'm reasonably sure they're in the correct positions using the plans and that 4-page addenda as a guide, and based on my understanding on how the valves and linkages are supposed to work. The engine seems a little "stiff" but turns by hand without difficulty. One valve was stuck when I got it, but I got that resolved and all four move freely without binding.

There are just a lot of variables, all inter-related, and just one of which throws everything else off. I'm hoping there's someone in this forum with some experience with this engine that walk me through it and perhaps tell me what I might be doing wrong.

Thanks again for taking the time to reply!

Well, "at rest" should mean 'not running'. I would thimfpk the writer of this addenda would know that and assume that. However, that is what is so confusing--I wonder if he means TDC or BDC, which is exactly where you will want the piston to be?

 

[Richard Hed]

I followed your instructions. The steam valve starts admitting air very early, somewhere around 45 degrees before TDC. It can be tweaked a little with the front adjustments, but nothing close to that much. I wonder if the eccentric might be off. Those four page instructions talk a bit about the eccentric, but (to me at least) they seem backward (contrary to what I'm seeing and the overall drawing on the plans).

45deg? That valve should JUST be opening--You need to reset the valve stem?