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gamh44
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Joined: Tue Mar 24, 2015 4:03 pm
Location: Australia

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Post by gamh44 »

All

I am looking to bring the locomotive below back into service after around 13 years of hibernation and am looking for some advice.
The attachment IMG_3044.PNG is no longer available
The issue I am faced with is stuck valves. The bottom valves on both gauge glasses, the blower valve and the throttle valve are all unwilling to move. All other valves (and there's quite a few!) move freely. Here are offending valves in the cab:
Stuck Valves
Stuck Valves
With the dome removed, the slide valve regulator can be seen:
Regulator
Regulator
So what to do? I would like to think that steaming the boiler might provide enough heat to coax the valves to open but I would like to do a hydraulic test before doing that, just to be sure.

The engine has a copper boiler, if that matters.

Any and all advice appreciated.

Geof
blff cty lcmtv wrks
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Re: Return to Service

Post by blff cty lcmtv wrks »

have you tried loosening up the bonnet, or what ever it is called, just a bit while trying to open the valve? a very wise old gentlemen who had a great knowledge of live steam told me that when you shut down a hot engine for the day, that as it cooled off, it would contract in size somewhat, and that would cause an already shut valve to shut even harder and possibly stick shut. his remedy was to loosen the bonnet, while trying to open the valve , and when the handle was freed up, tighten the bonnet back, while holding the valve open. his advice was to leave all valves open about a half turn. it has worked for me. jmho.

big c
bluff city locomotive works
Pontiacguy1
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Re: Return to Service

Post by Pontiacguy1 »

What scale/gauge is this? Reason to ask, what size are the valves in the photos? Are they 3/16" model taper pipe, or 5/16" MTP, or something else? Cecil is right... Just cracking the valves after you blow down will keep them from sticking. Not only does the metal contract from cooling and make a valve stick harder, but any scale that's in there will get on them and almost glue the parts together. Cracking the valves and then opening/closing them a couple of times before firing up will help to keep them freed up and in good shape.

Have you tried putting a little bit of oil down in the throttle valve? It looks like a slide plate in there, and a little bit of oil on it isn't going to hurt anything. Also, maybe back off of the packing gland and make sure that it isn't stuck. Usually, the throttle rod going through the packing and into the boiler is made from Stainless, but I've seen people use mild steel before, and it would actually rust in place if you left it. In that case, what we had to do was store it with the throttle about half-way open and use oil in the packing. When you went to fire it up after a few months or more of storage, you would put a little bit of oil on the packing, and then you could work the throttle lever in and out. If you left it all the way in, it would be stuck pretty hard and it was a lot of trouble getting it to work.

Very nice looking locomotive, by-the-way.
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gamh44
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Location: Australia

Re: Return to Service

Post by gamh44 »

Thanks for the replies.

Yes, I am not sure why these valves were closed after its last run back in 2004 - it was (and still is) regular practice. All the other valves were at least cracked open. In saying that, the regulator looks like it is slightly opened. Could mean the problem is at the control end which would be good news, i suppose.

The engine is 3.5" gauge in 3/4" scale (I believe). I am not sure of the exact threads on the valves, although I should be able to find out by removing one of the other ones. I would think they will all be the same.

I have doused the dry pipe to the regulator with light oil with no luck at this stage. Hopefully the problem is at the other end. I am confident (although testing my memory) that the regulator control is all stainless.

I will have a look at loosening the gland nuts and see if that helps and report back.
Pontiacguy1
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Re: Return to Service

Post by Pontiacguy1 »

Don't worry about the pipe sizes, I was just trying to get an idea of the size you have, and it being 3/4 scale tells me that they are pretty small.

Try taking the packing loose or even take it out if your throttle is still stuck.
James Powell
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Re: Return to Service

Post by James Powell »

If it's a 3/4" engine, and a copper boiler, I would fill the boiler, and use a medium propane torch to gently bring it up to just past boiling, then try the valves again with it all warm.

Steel boiler- hydro first...or at least try tapping in the corners of the firebox with a screwdriver...

If the valves are truely closed, then you should be able to at least hydro for getting some steam (& warming everything up) without any difficulty.

James
Mike Walsh
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Re: Return to Service

Post by Mike Walsh »

Regarding the throttle... You mentioned that it could be seized at the control end. I doubt it, but stranger things have happened. Quick way to check is...

Disconnect the throttle lever from either the actuating rod (that goes through the boiler) or from it's mounting bracket -- Do either of these two pivot points show evidence of seizing? No? Can you turn the actuating rod? You will likely not be able to turn it fully due to the other end of the actuating rod being mounted on the throttle block, but you should be able to see some degree of motion... This would help verify that the throttle actuating rod is not seized in the packing of the backhead. You could also try loosening the packing around the actuating rod... But the key word is Loosen... Don't remove it fully. Not yet, anyway. I would handle this a number of different ways, but I cannot make further recommendations without actually seeing, feeling the locomotive.

Also... Get the right tools. Don't use a 8" crescent wrench to remove the valve bonnets. Use the proper size box end wrench. Craftsman offers miniature crescent wrench sets. I splurged on this so that I had the right tools when the job called for it.
Kimball McGinley
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Re: Return to Service

Post by Kimball McGinley »

The best wrench for hollow valve packing nuts etc. is a "tubing wrench" or my A + P mechanic friend called them "line wrenches." These are 6 points as opposed to 12 points in a regular box end wrench and so they grip the hex more securely. They also feature a slot that fits the tubing to be able to access flare nuts.
SteveM
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Re: Return to Service

Post by SteveM »

Kimball McGinley wrote: Wed Mar 28, 2018 11:55 am The best wrench for hollow valve packing nuts etc. is a "tubing wrench" or my A + P mechanic friend called them "line wrenches." These are 6 points as opposed to 12 points in a regular box end wrench and so they grip the hex more securely. They also feature a slot that fits the tubing to be able to access flare nuts.
I've seen them called "flare nut wrenches".

If you can slip a box wrench over the nut (e.g. by removing the valve handle) then a set of ignition wrenches might wok nicely.

Here's what a flare nut wrench looks like:
gearwrench-open-end-wrenches-81648-64_1000.jpg
Steve
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gamh44
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Re: Return to Service

Post by gamh44 »

Thanks to all. Some excellent advice. I should get a chance to have a closer look over the weekend and will post my success.
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