It is currently Sat Aug 19, 2017 8:31 pm

All times are UTC - 5 hours [ DST ]




Post new topic Reply to topic  [ 7 posts ] 
Author Message
 Post subject: Piston Valve Rings
PostPosted: Tue Aug 08, 2017 5:58 pm 

Joined: Sun May 03, 2009 11:52 am
Posts: 21
Location: Calgary, ALberta, Canada
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


Offline
 Profile  
 
 Post subject: Re: Piston Valve Rings
PostPosted: Tue Aug 08, 2017 6:31 pm 

Joined: Sun Aug 22, 2004 7:19 am
Posts: 5175
Location: southeastern USA
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.

_________________
"Techies never minded eating bits and jots of their work. They were grit and grease inside and out and could turn a pile of junk into a magical kingdom."

Andrea Hairston


Offline
 Profile  
 
 Post subject: Re: Piston Valve Rings
PostPosted: Wed Aug 09, 2017 12:58 pm 

Joined: Mon Aug 23, 2004 2:09 pm
Posts: 349
Location: Los Angeles
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.


Offline
 Profile  
 
 Post subject: Re: Piston Valve Rings
PostPosted: Wed Aug 09, 2017 1:07 pm 

Joined: Thu Apr 14, 2005 9:34 pm
Posts: 1825
Location: Copenhagen, Denmark
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.

_________________
Steven Harrod
Lektor
Danmarks Tekniske Universitet
Institut for Systemer, Produktion, og Ledelse


Offline
 Profile  
 
 Post subject: Re: Piston Valve Rings
PostPosted: Wed Aug 09, 2017 3:43 pm 

Joined: Wed Jun 13, 2012 10:38 pm
Posts: 229
Location: Copenhagen, Denmark
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

_________________
Stuart Harrod
Steam shop machinist
Nordsjællands Veterantog
Veterantoget.dk


Offline
 Profile  
 
 Post subject: Re: Piston Valve Rings
PostPosted: Wed Aug 09, 2017 4:48 pm 

Joined: Sun Aug 22, 2004 7:19 am
Posts: 5175
Location: southeastern USA
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......

_________________
"Techies never minded eating bits and jots of their work. They were grit and grease inside and out and could turn a pile of junk into a magical kingdom."

Andrea Hairston


Offline
 Profile  
 
 Post subject: Re: Piston Valve Rings
PostPosted: Wed Aug 09, 2017 5:53 pm 

Joined: Sun May 03, 2009 11:52 am
Posts: 21
Location: Calgary, ALberta, Canada
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


Offline
 Profile  
 
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 7 posts ] 

All times are UTC - 5 hours [ DST ]


 Who is online

Users browsing this forum: Google [Bot], Yahoo [Bot] and 36 guests


You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot post attachments in this forum

Search for:
Jump to: