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Post by peter99 on Feb 25, 2023 18:20:48 GMT
My Y4 Loco has not had much attention over the last 2/3 years mainly for the reason that I wanted to up grade my air brush capable air compressor to something like what I have now, a Burisch 3HP 90L 14cfm belt drive, which really I needed to get suitable for steam. What a beast! I keep it in my garage/workshop and it's up to pressure in 2/3 minutes then all is silent. The family, the other side of the wall, are unaware of it. I needed something like this to test the loco and trace for air leaks and very good the Burisch is! One air leak I have rather perplexes me and that is with the regulator closed air is issuing up the chimney from the cylinder exhaust pipes. Can anyone advise where this air leak could be originating from? There is no movement from the wheels/linkage.
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uuu
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Post by uuu on Feb 25, 2023 19:41:35 GMT
At IWMES, we have a club loco that had a similar air leak. Clearly the regulator was leaking - but also the slide valves used to lift, and stick onto the upper surface of the valve chest, so the gas could just flow straight from inlet to exhaust - no movement from wheels.
We milled ridges into the upper surface of the valve, to discourage it from sticking. OK - we had all sorts of other issues - but this would give the symptoms you describe.
Wilf
PS,- unless you have piston valves, of course.
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Post by peter99 on Feb 25, 2023 20:19:47 GMT
At IWMES, we have a club loco that had a similar air leak. Clearly the regulator was leaking - but also the slide valves used to lift, and stick onto the upper surface of the valve chest, so the gas could just flow straight from inlet to exhaust - no movement from wheels. We milled ridges into the upper surface of the valve, to discourage it from sticking. OK - we had all sorts of other issues - but this would give the symptoms you describe. Wilf PS,- unless you have piston valves, of course. Many thanks Wilf! I will try adjusting the regulator (by spring adjustment) and then move on to the valve chests with it's slide valves. Have got to do something as the loss of air is considerable but still leaving sufficient for a good turn of revs to the wheels on the rolling road at 80/90psi. Presumably by milling the ridges on the slide valves would give extra area for downward pressure.
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uuu
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Post by uuu on Feb 25, 2023 20:40:30 GMT
We thought the ridges were worth trying - we couldn't see any downsides. There would be no change to the downward pressure in normal operation - the opposite side components of each ridge would cancel each other out.
Wilf
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Post by peter99 on Mar 5, 2023 16:00:09 GMT
I removed the inner steam dome, but not without some effort separating the close fitted joint where I had applied locktite 574. and adjusted the Regulator which has reduced the omissions somewhat up the chimney. What omissions there are up the chimney I will except for the time being, but I think I have a problem with the RH cylinder as I have noted when operating the water drain tap's there is reduced air pressure compared with the LH cylinder. The flange of inner steam dome has now been sealed satisfactorily using Granville liquid gasket with light oil on one face.
I have another query which I would like advice. After an on the trolley steam test I am proposing to have a short 25 ft straight test track, ali rail with plastic sleepers, on the brick patio with the track cushioned using a strip of fake grass. Would this be OK in the short term? That is my query. I am hesitant for the time being of having a track on the lawn as access is down steps from the patio and there is a mowing the lawn problem. Doug Hewson's write-up mentions I believe a 10ft radius, but I could do a 12ft rad. And whatever the pundits say the Y4 is not a one man lift! Well not for me it isn't! The family just wants to see the Y4 in motion as it has taken 18 years to get to this stage but one does get involved with other things!
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uuu
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Post by uuu on Mar 5, 2023 17:47:12 GMT
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