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Well, after what seems like forever, I find myself at the point where I am tuning my roundhouse liberty belle. The nice folks at RH sent me some O rings which I used to seal the steam inlet pipe. One thing on that - the steam pipe and the T have a gap of about 1/16". I put in two of the O rings, and there seems to be enough compression to hold the 20 PSI I can generate with the hand pump. Hoping that hot steam will further seal that connection. I assume this is how these are to be connected, but somehow think that the steam pipe should actually extend in to the T, at least a little bit.

So, tuning. This is fun! I was making small adjustments and not really get anywhere, so I opened up the valve chest covers and tried to do it by setting the slide valves at about the same place, thread count wise. It looked like I had it timed about right, and applying pressure, I was treated to some pretty rough running. Eventually, I got to the point where in reverse, I was getting nice smooth movement, even as low as half a pump stroke (maybe 5 PSI). Surprisingly, forward is very rough. So it seems I am biased toward reverse running. I can feel the valve is not closing when the left piston is reaching TDC (through back pressure). I can force it to move, and at the higher pressure, the other side seems to be able to push it through. But, that's not how I want it to run. I try and make small adjustments (1/2 turn or full turn of the D valve), but is there another way? Just to be sure, looking from the cab toward the piston, turning the D valve clockwise moves the slider toward the valve gear.

I did add some steam oil to the valve chests, so hopefully, that is making its way down in to the cylinders.


I think the most challenging part of setting the timing is trying to figure out which side to try and adjust. Does it make sense to leave one side alone and set the other? Is there a 'more scientific' way to set valve timing? Either way, I enjoyed last evening's session, even if it was a little frustrating. When I emerged from the workshop, it was midnight. I wonder if that is the sign of a problem...
 

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David,

That's why I added a second O ring. Not sure why it doesn't go all the way in to the T, since both steam feed pipes are the same as before. Maybe I have the one side in too far. Thanks for the feedback.

Mark
 

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Posted By markoles on 02/06/2009 10:52 AM
Snip.... I wonder if that is the sign of a problem...



Yes, it is a sign. When you are ready to admit to yourself and others that you are a steam-aholic, go pick a number.


Mark, if you have never read through (or at least not recently) Dave Hottman's tuning article, it's good just to go over now and again. Check it out. (I have a copy that I printed out a while back, on a clip board on my work bench.) Ruby tuning, from the archive
 

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You first set the angle of the eccentrics (90-deg for Walshearts, Baker, Southern and others, other angles for Stephensons and a few others, slip eccentrics are another kettle of fish... make sure you understand where that angle is measured!) then you adjust the radius rod/valve rod length for equal exposure of the front and rear ports as the wheels rotate.
 

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Charles and 'dawg,

Thanks for the tips. I did check out the Ruby tuning PDF, and it was helpful. I went back the RH site, and downloaded the PDF concerning the Walscharts Valve Gear. This one appears to have all the info about timing, plus diagrams, and since it is a PDF, printing it out is much easier.

Mark
 
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