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Old 04-24-2020, 02:44 PM   #21 (permalink)
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The valve functions as a two part unit. The center of that stainless steel valve stem is hollow bored straight down to the cross hole, so it functions as any other goodall valve would.

The slotted head of the shaft sits atop a o-ring seal, which is pulled down from below by the spring and nut assembly, which makes a safety valve (albeit a crude one).

In addition to what Pete said above, there should be a piece of stainless (or brass) wire through that lower hole in the base of the valve stem.

That will hold the goodall tubing (1/16" ID aircraft silicone fuel tubing works fine) in place and prevent it from being shot down into the boiler when the pump bottle is used.

The stack works like this:
Valve stem comes down from top of valve
O-ring under the valve stem head (silver threaded shaft with holes)
Spring and nut from bottom of valve body
Tubing on shaft with cross hole
Wire stopper on bottom cross hole.

Will take a photo of an assembly if that helps
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Old 04-24-2020, 05:51 PM   #22 (permalink)
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Thanks so much.

This is really helpful. The rubber tube must have broken into pieces and unfortunately, most of it is inside the boiler now. The little piece of wire/cotter pin is also inside the boiler now. I will need to make or find a replacement unless I can get it out of the boiler.

I will see about finding a piece of that tubing as well. A picture would be very helpful.

It is not the fill valve that allows you to fill the boiler while warm though. It's the regular boiler fill that you can only open when cold.

IMG_7863 by G.T. Keplinger, on Flickr

It's the one on the right in the above photo. The "goodall" valve is the one on the left unless the other valve is also technically a goodall valve.




Quote:
Originally Posted by rbednarik View Post
The valve functions as a two part unit. The center of that stainless steel valve stem is hollow bored straight down to the cross hole, so it functions as any other goodall valve would.

The slotted head of the shaft sits atop a o-ring seal, which is pulled down from below by the spring and nut assembly, which makes a safety valve (albeit a crude one).

In addition to what Pete said above, there should be a piece of stainless (or brass) wire through that lower hole in the base of the valve stem.

That will hold the goodall tubing (1/16" ID aircraft silicone fuel tubing works fine) in place and prevent it from being shot down into the boiler when the pump bottle is used.

The stack works like this:
Valve stem comes down from top of valve
O-ring under the valve stem head (silver threaded shaft with holes)
Spring and nut from bottom of valve body
Tubing on shaft with cross hole
Wire stopper on bottom cross hole.

Will take a photo of an assembly if that helps
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Old 04-24-2020, 06:59 PM   #23 (permalink)
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Not as such. The one on the left in that photo is the primary safety valve. There should be a cap on it (assume it's removed for the photo)which routes the venting steam down through the copper pipes astride the boiler.

The hole on the right is for the part in question earlier. That is the Goodall valve and also has a secondary feature of a backup pressure relief valve, should the primary fail to vent enough steam or function properly.

Don't worry about the tube and cotter pin/wire loop being in the boiler. They are inert in this case and the wire will settle to the bottom of the boiler without issue. The tubing will not harm anything.

A cotter pin will do OK to replace the original safety wire, but beware you need a stainless steel one or it will rust with time.

Unless the tubing is replaced, the double function goodall/safety valve will continue to leak steam from the goodall portion of the valve, regardless of the tension on the spring for the safety valve spindle.

Pictures of how it should look forthcoming.
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Old 04-24-2020, 07:05 PM   #24 (permalink)
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Quote:
The center of that stainless steel valve stem is hollow bored straight down to the cross hole, so it functions as any other goodall valve would.
So it's a Goodall valve inside a safety, so it can bounce up if there's enough pressure. Amazing.
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Old 04-26-2020, 05:18 PM   #25 (permalink)
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Thanks again for the advice and help. I went to a local RC Hobby Shop near me yesterday and they gave me some short pieces of tubing in two diameters and I bought some piano wire. I know it will rust but it's working for now until I can get some stainless wire. Here's a picture of the rebuilt valve and a video of the Mikado running. It made all the difference in the world.

https://www.flickr.com/photos/188081...posted-public/

https://www.flickr.com/photos/188081...posted-public/


Quote:
Originally Posted by rbednarik View Post
Not as such. The one on the left in that photo is the primary safety valve. There should be a cap on it (assume it's removed for the photo)which routes the venting steam down through the copper pipes astride the boiler.

The hole on the right is for the part in question earlier. That is the Goodall valve and also has a secondary feature of a backup pressure relief valve, should the primary fail to vent enough steam or function properly.

Don't worry about the tube and cotter pin/wire loop being in the boiler. They are inert in this case and the wire will settle to the bottom of the boiler without issue. The tubing will not harm anything.

A cotter pin will do OK to replace the original safety wire, but beware you need a stainless steel one or it will rust with time.

Unless the tubing is replaced, the double function goodall/safety valve will continue to leak steam from the goodall portion of the valve, regardless of the tension on the spring for the safety valve spindle.

Pictures of how it should look forthcoming.
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Old 04-26-2020, 09:57 PM   #26 (permalink)
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Excellent work! You'll want to cut the tube just a little shorter so it isn't up in the threaded section. Otherwise, it'll start to leak past there eventually.
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Old 04-27-2020, 10:14 AM   #27 (permalink)
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Looks good. It almost made me think of buying one - I know where there are 3 for sale for $650 each.


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I bought some piano wire. I know it will rust
Almost anything will stop the tube falling off. A brass rod, small brass nut-and-bolt, brass strip, etc.
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Old 04-27-2020, 09:29 PM   #28 (permalink)
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That's a good price. I might be tempted to buy another one.

I know the B&O had 100 of them.

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Looks good. It almost made me think of buying one - I know where there are 3 for sale for $650 each.



Almost anything will stop the tube falling off. A brass rod, small brass nut-and-bolt, brass strip, etc.
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Old 04-27-2020, 09:30 PM   #29 (permalink)
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Thanks again for the tip. I will trim it a little bit before I run it again. My kids were asking me to run it again today. Maybe tomorrow.

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Excellent work! You'll want to cut the tube just a little shorter so it isn't up in the threaded section. Otherwise, it'll start to leak past there eventually.
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Old 04-28-2020, 11:08 AM   #30 (permalink)
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Quote:
That's a good price. I might be tempted to buy another one.
There are some 0-4-0s too.


https://forums.mylargescale.com/138-...1-new-2-a.html
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