Andrew C
Part of the e-furniture
Posts: 447
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Post by Andrew C on Aug 22, 2014 20:40:39 GMT
HI some advice from the experts is needed here.
I steamed my 5in Britannia today
I have a squeak that seams to be from one side and also I think one direction of the stroke although cant be sure. It only occurs under steam as the loco pushes along freely.
I also have a distinctly woolly exhaust beat.
Am I correct in thinking that these are both symptoms of bad fitting piston valves ?
I am still not happy that the lubrication is satisfactory but that is mostly down to the fact the loco has not done much mileage yet
Any Ideas?
Andrew.
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pault
Elder Statesman
Posts: 1,496
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Post by pault on Aug 22, 2014 21:06:53 GMT
Hi Andrew
the squeak could well be a piston gland blowing
Regards
Paul
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Post by Deleted on Aug 23, 2014 8:58:42 GMT
Hi Andrew
I sometimes get this with my Modelworks Britannia. It was more frequent before I fitted the PTFE piston valve rings, but it still happens from time to time. As you say, it seems to be on one side and on one direction of stroke. The experts at my club thought it sounded like a whistle of escaping steam rather than a metal-on-metal squeak. I think it probably happens when one of the lubricators is not pumping properly. It seems that the lubricators can develop air locks if you let the tank empty completely, so even if the spindle is turning it may not be delivering oil. The lack of oil perhaps lets more steam blow past the valves, or perhaps as Paul says past the piston gland.
Kind regards, John
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Post by Deleted on Aug 23, 2014 9:16:24 GMT
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Andrew C
Part of the e-furniture
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Post by Andrew C on Aug 23, 2014 21:49:45 GMT
I spent a good hour and a half re packing the piston gland. Ran on aid and it still squeaks. There was little or no packing in them. Thanks anyway Paul they needed doing.
John I think you are on to something there. If you open the regulator just right you can stall the engine at the point the squeak starts. Having then wandered around listening the sound is coming up the blast pipe, using a screwdriver as a stethoscope you can hear the sound coming from one of the piston valves.
The lubricators are not working to my satisfaction yet.
Tomorrow's job is to pore some steam oil in and see if after it has been spread about a bit the squeal stops
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Post by Jim on Aug 23, 2014 21:51:34 GMT
Good to hear from you John.
The clips of Britannia running, with or without squeaks, is great and has given me quite a few ideas for the day, hopefully soon, when Boadicea at last runs under her own steam.
Jim
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Post by Deleted on Aug 24, 2014 9:09:18 GMT
Hi Andrew That's quite reassuring - if you can get it to squeak or squeal when the engine is stalled, that proves that it's a steam (or, in your case, air) leak and not a nasty mechanical rubbing problem. I've also noticed that it only happens when the regulator is partly open - it stops if I close the regulator and coast along, or, more surprisingly, if I give it full power. Incidentally I think that if I were to try running on air now after fitting PTFE valve rings there would be dreadful leakage past the cold rings. Here's another video for you, Jim, showing the engine starting off with cold rings and you can see the initial blast up the chimney which stops after a couple of seconds as the rings warm up: www.britanniabuilder.com/Steamingvideo010511.wmvKind regards, John |
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Andrew C
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Posts: 447
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Post by Andrew C on Aug 24, 2014 20:37:35 GMT
Glad you can see the vids safari can't show them on my phone and internet explorer just hangs. Will have a fiddle with some settings and see what I can do. On the engine front ran for about half an hour before failing the loco due to the right hand mechanical lubricators non return valve becoming a allow steam into the oil valve  Still we ran for a bit at my granddaughters 1st birthday. Steamed the 56xx instead for a while but that also need some TLC (30 years old now). Kept the kids happy for a while. The plan is to get the work shop back in operation then check the piston valves for size (both ends of the bore) and remake the PTFE rings. |
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Post by Deleted on Aug 25, 2014 8:52:26 GMT
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Andrew C
Part of the e-furniture
Posts: 447
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Post by Andrew C on Aug 25, 2014 22:13:07 GMT
Hi john
Yes thanks for that. It sounds a very similar noise, albeit I think quieter on yours. It's difficult to tell with the background noises generated by the speed she is running. I have not got Robert Burns up to that sort of speed so the noise is more pronounced.
I have the lighting done on the workshop today so need now to install the sockets and I can then begin to place the machines and work bench. Once that is done we are on to fixing the valve gear and lubricators.
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