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| Piston Valve Rings http://www.rypn.org/forums/viewtopic.php?f=1&t=40999 |
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| Author: | Brian Manning [ Tue Aug 08, 2017 5:58 pm ] |
| Post subject: | Piston Valve Rings |
Over the weekend one of our locomotives went down with broken ring(s) on the l/s piston valve. This is no real problem as I have dealt with this before on another engine, however this time its being a bit obstinate. I got the valve rod out of the cross slide and the piston valve moves freely in the cylinder but stops dead just short of the first ring coming out. I'm assuming that it is being hung up on a ring in one of the other ports in the sleeve. Any trick in getting the valve to come out? Brian Manning |
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| Author: | Dave [ Tue Aug 08, 2017 6:31 pm ] |
| Post subject: | Re: Piston Valve Rings |
If it is a common built up valve piston assembly, you can disassemble it in the bore and remove it piece by piece. Might try opening the ports and looking for broken ring chunks fouling the ports holding the whole thing in. |
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| Author: | Bobk [ Wed Aug 09, 2017 12:58 pm ] |
| Post subject: | Re: Piston Valve Rings |
As Dave mentioned something is getting stuck in the port, a broken ring can do this. Push the valve spool back past the port and if you can rotate the assembly and try again. If the ring piece is in fact falling into the port then rotating the assembly will perhaps bring a larger ring piece to the bottom where it won't fall into the port. |
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| Author: | softwerkslex [ Wed Aug 09, 2017 1:07 pm ] |
| Post subject: | Re: Piston Valve Rings |
We had a problem like this last week. We had a lot of debris and rust in the valve chamber, both sides. We hammered the valves out with a sledgehammer. It took a lot of heavy blows. Something tells me it wasn't the best method. |
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| Author: | 10stewi [ Wed Aug 09, 2017 3:43 pm ] |
| Post subject: | Re: Piston Valve Rings |
Ill further details my dad provided by mentioning this was rust that had built up for 10 plus years of outdoor storage. It resulted in some thick stubborn rust hiding in the steam portion of the valve cage. This was like the problem described above, where the valve slid beautifully in the normal travel ranges, but became a b**ch outside of this. I will also mention upon cleaning the oil away from the normal travel sections that the surface held a good polished appearance. When removing the valve, I held a thick oak block between the sledge hammer and the rod stem. Measurements with a high quality caliper showed there was no increase or damage in the diameter of the valve stem (also no bends). Upon removing the second valve, we used a better method. We have a large gear puller where the arms are mounted in sliding blocks on an inverted T profile. The arms can be slid off and reversed. We used this by sticking the ends of the arms in the exhaust ports and the threaded screw with a block of bronze in between on the valve stem. Some areas it worked like a dream, and in others it required small hammer taps on the end of the threaded rod before moving and repeating the tightening process. From experience and effort involved....I would recommend the second process |
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| Author: | Dave [ Wed Aug 09, 2017 4:48 pm ] |
| Post subject: | Re: Piston Valve Rings |
Hygge, there's a huge difference between a valve removal from a working locomotive and from one that's been sitting and rusting for years. If a sledge hammer and heavy puller is required for a working locomotive, something has been terribly wrong with it for a long while...... |
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| Author: | Brian Manning [ Wed Aug 09, 2017 5:53 pm ] |
| Post subject: | Re: Piston Valve Rings |
Thanks, and as BobK mentioned, we did push it back and tried to rotate it then pull ahead. After about 3 hrs of "playing" with it , it finally came out no problem., no oak blocks or sledge hammers involved:-) I can't think about all the damage that would do , since we are trying to get it repaired and back out on the road. New rings next week and should be good as new. Thanks Brian MAnning |
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