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Post by dhamblin on Mar 6, 2024 21:33:51 GMT
Ok, that's spooky, I think my one has the same problem! Occasionally put it in full forward gear, open the regulator and all you hear is steam escaping up the chimney. Give the loco a 'jerk' forwards and it starts moving with no problem.
Taking the cylinders off this month to do a re-packing exercise and fix the steam leaks, so might find something of interest.
Regards,
Dan
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Post by keith1500 on Mar 7, 2024 7:16:49 GMT
I had similar problem with my Speedy. The fault was valve sleeve where it was pressed into the block. The steam was short circuiting around it. Most notable when stationary.
I proved this by popping a snug fitting piece of PTFE, long enough to block off the ports. Applied steam or air and found it exiting the blast nozzle. You can open and close the cylinder cocks this will show if the leak involves the cylinder
Keith.
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JonL
Elder Statesman
WWSME (Wiltshire)
Posts: 2,909
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Post by JonL on Mar 7, 2024 17:18:10 GMT
Dan, could your issue be the snifting valve? On a slide valve engine I would suspect the valves were not seating, but as a Brit is piston valves it could be your snifting valve is leaking and it either sounds like your steam is going up the chimney or it really is and you have something amiss with your snifter!
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Post by dhamblin on Mar 7, 2024 20:36:11 GMT
Actually, I think Keith has hit the nail on the head. On the rear face of the left hand cylinder assembly, where the piston rod cover meets the valve chest cylinder I noticed the paint had bubbled and indeed was pulsing as the valve gear turned over. That makes me think there is a sealing issue between the valve chest cylinder and the bore it sits in, which would explain how it can bypass the valve arrangement.
Also, I've got a video from the November track test from the moment I started off with the cylinder drains open and an air temperature of around 5 deg C. The left hand cylinder is definitely doing something odd as the right hand one is giving sharp, clean expulsions of steam, whereas the left hand one is doing much shorter less intense bursts for part of each wheel revolution.
Might be worth checking your cylinder for same issue Jon, as it should display similar symptoms?
Regards,
Dan
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JonL
Elder Statesman
WWSME (Wiltshire)
Posts: 2,909
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Post by JonL on Mar 10, 2024 12:24:33 GMT
Yes that does sound quite likely. Oh what fun!
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Post by keith1500 on Mar 12, 2024 22:18:33 GMT
I wasn’t up for any major rebuilding in order to solve the problems. So, when I had a chance the cylinders came off and the repairs were done in two stages. The leak to the outside was exhaust to front where the sleeve protrudes beyond the cylinder block. This was solved with soft solder. I run a fillet around all four to ensure all leaks are solved. The internal leaks were solved by “injecting” liquid PTFE into the leak area. Basically, I filled the port with liquid PTFE and used compressed air to force it into the leak. Then blew the ports passageways clear and cleaned out the gunk with cotton buds etc. Check it for leaks and repeated as necessary or moved to another port.
It seemed to work okay. I haven’t done a lot of running so can not report on the success.
I wrote a short article for the club magazine. I’ll see if I have a copy of that helps?
Keith.
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JonL
Elder Statesman
WWSME (Wiltshire)
Posts: 2,909
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Post by JonL on Mar 17, 2024 18:51:16 GMT
So I used her yesterday and to my astonishment not only is the lubricator now delivering far better the cylinder leakage appears to have sealed itself. After some initial hesitation it ran beautifully all day, with the only minor issue being the reversing shaft drive universal joint slipping. I'm confused but happy...
A friend who owns a Polly 2 drove her and came back astonished at how powerful it is. I guess I hadn't noticed as i've been slowly tweaking it to improve but yes, I think for its size its a decently powerful locomotive now.
Thanks to everyone who answered to help me out above, it is all noted.
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