Author Topic: Arnold Throp Corliss Valve setting  (Read 2815 times)

Offline Les#053

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Re: Arnold Throp Corliss Valve setting
« Reply #15 on: January 27, 2016, 08:28:41 AM »
Hi everyone, thanks for the offer of help, it is really appreciated.

Jerry, I will try to get the photos and video done later today.

Les


« Last Edit: January 27, 2016, 12:54:34 PM by Les#053 »

Offline Les#053

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Re: Arnold Throp Corliss Valve setting
« Reply #16 on: January 27, 2016, 12:47:59 PM »
Hi Jerry

Attached is the link to the video, and some not very good photos.

Hopefully you might be able to see what I'm doing wrong!


Les


« Last Edit: January 27, 2016, 12:55:08 PM by Les#053 »

Offline vcutajar

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Re: Arnold Throp Corliss Valve setting
« Reply #17 on: January 27, 2016, 01:31:43 PM »
Les

I have been looking at you latest video in slow motion.  I do not know if it matters or maybe it's an optical illusion.  I noticed that the left hand inlet valve moves more than the right one.  In fact it seems that at some point it disconnects from that central pivot arm.

Vince

Offline Les#053

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Re: Arnold Throp Corliss Valve setting
« Reply #18 on: January 27, 2016, 03:22:41 PM »
Hi Vince

Yes you are right, that is the last video I have of it running and I think that was one of the things I thought I was correcting
and I haven't had it running since.

Serves me right for making multiple changes without testing between them!

Just found the answer to one of my questions, there is a note on the drawing to say that the steam eccentric leads the crank by 42 degrees and the
exhaust follows by 45 degrees.

I decided to try and check this, the only way I could think of without dismantling the crankshaft was to count the barring teeth on the flywheel as they looked fairly even.
I set the steam eccentric to its high point using a DTI and marked a tooth, I then moved the crank to the vertical position and counted the teeth.

96 barring teeth = 3.75 deg/tooth X 14 teeth = 52.5 deg for Steam and 11 teeth = 41.25 for Exhaust

Can anyone see any glaring errors in this fairly crude method?


Les

Offline Captain Jerry

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Re: Arnold Throp Corliss Valve setting
« Reply #19 on: January 27, 2016, 04:23:14 PM »
Les

Thanks for the new pictures.  Very easy to see and analyze.  There is one more piece of information that is needed.   That is where does the valve actually open?  It appears from the pics that the valves use inside admission but it is impossible to actually see the valve in relation to the control arms which are very visible.  Full size corliss engines have a witness mark on the opposite end of the valve stem that shows this.  The bonnet on the other side of the cylinder must be removed  to see it. Here is aa link to an article that gives a lot of detail on vaalve adjustment.  You will have to go down to figure 877 and 878 to see this.  There is a lot of additional information that pertains to valve gear that is quite different from yours.  Don't let it confuse you.  If your model does not have these marks you may want to look into it.  It is a critical piece of the adjustment.  It is usually adjusted  by loosening the steam arm on the front of the cylinder and rotating it in relation to the valve.

My guess at this point is that is where the problem lies and when that is set properly, the engine will run in the right direction.

I do not claim to be an expert on this subject but I have invested a lot of time reading as much of the old literature as I can find in order to get a couple of Corliss engine to run.  A lot of the older articles a difficult to understand and may need ro be re-read a time or two or more.  Thanks to the internet all of that expertise is available.  Keep us posted on your results.  I am truly interested.

By the way, that is a very nice model with a lot of interesting mechaanical detail that I have not seen.  One of the reasons that I like Corliss engines is the great number of ways that were devised to do the same thing.

Jerry
There are thing that you can do and some things you can't do.
Don't worry about it. try it anyway.

Offline Les#053

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Re: Arnold Throp Corliss Valve setting
« Reply #20 on: January 27, 2016, 05:29:22 PM »
Hi Jerry

Picture one shows the left hand exhaust just beginning to open and the right hand one fully closed, picture two shows the right hand side.

It seems to be impossible to stage the inlets for a picture as they are held apart by a spring between them and I ran out of hands.

I've included a PDF of the theory if everything had been made to dimension.

You mentioned about a link to an article but I can't seem to see it.


Les

Offline Captain Jerry

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Re: Arnold Throp Corliss Valve setting
« Reply #21 on: January 28, 2016, 12:37:59 AM »
Les

My apologies for not including the link to the referenced article.  Here it is:

http://www.wkinsler.com/technology/corliss/figures/index.html

I hope it makes sense.  The witness marks on the opposite end of the valve shaft makes it possible to see exactly when the valve opens or closes.   Just to re state the situation, with the bonnet on the backside of the cylinder there should be a witness mark on the frame that corresponds to the opening edge of the valve face.  On the end of the valve shaft, there should be a witness mark that corresponds with the leading edge of the valve.  If there are no such marks, it would be very worthwhile to create them, even if it means taking the valve apart.

From looking at the second video and the first set of photos, my best guess is the position of the arm on the front end of the valve shaft is not correctly set,  This is probably true on all four valves.

Jerry
There are thing that you can do and some things you can't do.
Don't worry about it. try it anyway.

Offline Captain Jerry

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Re: Arnold Throp Corliss Valve setting
« Reply #22 on: January 28, 2016, 12:53:30 AM »
The reference marks are also shown in figure 960.

There are thing that you can do and some things you can't do.
Don't worry about it. try it anyway.

Offline Les#053

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Re: Arnold Throp Corliss Valve setting
« Reply #23 on: January 28, 2016, 11:55:28 AM »
Jerry

Thanks for the link, really interesting article, if what you need to know about Corliss valves isn't there it isn't anywhere.

I've been doing a lot of thinking and decided that if those eccentric keys are really as far out as I believe they are I'm never going to get this running right.
It would also explain why I can't seem to get the exhaust valves synchronised with the steam valves.

So, reluctantly, I'm going to do a complete strip down, check those key-way positions accurately and do a few other things such as put those valve position markings in, make
a few new gaskets etc.

It maybe a little while before I have any progress to report as I'm quite slow and don't get as much shop time as I would like.

Will keep you posted on the outcome Jerry.


Les

Offline Captain Jerry

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Re: Arnold Throp Corliss Valve setting
« Reply #24 on: January 28, 2016, 02:02:08 PM »
Les

Congratulations on your decision to work it out.  If things don't seem to be working like they should, you need to get to the bottom of it.  The eccentrics may be a part of it but your measurement of the angles show that they are set pretty close to the design and I think your method was valid.  It seems odd that they are keyed in, particularly as the reference source shows a setup called "squaring the valves" that involves adjusting the eccentrics.

Good luck with your investigation.  I know that the referenced source will be a great  help as it has been for me.

Jerry
There are thing that you can do and some things you can't do.
Don't worry about it. try it anyway.

Offline Les#053

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Re: Arnold Throp Corliss Valve setting
« Reply #25 on: March 30, 2016, 04:30:35 PM »
Still can't get this engine to run in the correct direction, and as Alan commented this means that the crosshead is pulling up into the keep plates rather than down into the bed.

Either I have interpreted the drawings incorrectly (a distinct possibility) or the drawings are at best misleading.

Picture N01 shows the information given on the plans, I've assumed from this that the crank is at TDC as shown in picture N02 Fig A.

Earlier in this post Jerry suggested that he believes the exhaust should lead the inlet and as he is clearly very knowledgeable on Corliss valve gear I intend to take his advice and modify
the keyways accordingly.

What I can't decide is whether to follow Fig B and leave the leading and trailing angles the same, or follow Fig C and swap the angles as well.

I have been in touch with Bob Potter from Southworth Engines who has been very helpful and sent me loads of pictures, but he hasn't got this far on his engine yet
and as he says people don't always notify him of any errors found. He is very kindly trying to contact people he knows who have completed the engine but has not got back to me yet.

Any ideas would be much appreciated


Les

Offline Les#053

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Re: Arnold Throp Corliss Valve setting
« Reply #26 on: May 19, 2017, 11:27:58 AM »
Well I did wonder at times whether I would ever get there, it still needs some fine tuning as it doesn't run that smoothly,
hopefully it just wants running in. It seems to need a lot of air, 25 PSI and will not tick over very slowly.

My thanks to Colin Palmer for the pictures he sent me, they really helped, and to Terry Fleet for the chat we had on the phone,
it was his suggestion that I might have the valves 180 degrees out that was the turning point, I had indeed got the inlet valves wrong.



Offline vcutajar

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Re: Arnold Throp Corliss Valve setting
« Reply #27 on: May 19, 2017, 12:16:50 PM »
Glad you managed get it running.

Vince

Offline Alan Haisley

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Re: Arnold Throp Corliss Valve setting
« Reply #28 on: May 24, 2017, 12:43:25 PM »

An engine that pretty SHOULD run!

Near Raleigh, NC, USA

Online crueby

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Re: Arnold Throp Corliss Valve setting
« Reply #29 on: May 24, 2017, 02:15:47 PM »
That is VERY nice! Wonderful sound to it.