-steves- wrote: ↑
Wed May 29, 2019 3:27 pm
you may also hear a clunking noise coming from the engine, not sure what this is as yet but I have not sat down and looked yet either. I had it all running as smooth as silk at one point this morning, but since putting it back together it has a few tight spots again,
I've found it pays to walk away if things aren't going right. While you mull it over in the back of your mind, eventually the answer comes to you........
Well done, you must have made the parts properly, or it would never have worked. If it has run well once, then it can be made to run again.
Does the chassis turn over smoothly by hand when not connected to the compressor? If not, you may have reversed a wheelset, or swapped rods when reassembling things. It shouldn't make a difference, but sometimes the tolerances add up the wrong way and some parts have only one orientation where everything works smoothly.
If the wheels and rods aren't binding, then it may be the valve timing that is out. With these little locos, the valves should be set line for line. Unlike larger scale and full size locos, any advance will make them run lumpy, as they don't have the weight and therefore momentum to compress the steam (or air) if the valve opens early, before the crankpin is at dead centre.
Also check that the piston rods are pushed into the crossheads far enough and aren't hitting a cylinder end cover. Been there.....
I've never built a slip eccentric loco, but FWIW my valve setting procedure should work.
- Centre the slide valve first, by adjusting the valve position on the valve rod so the valve openings are the same at each end, in both forward and reverse, or as near as you can get them. At this point it doesn't matter exactly where the eccentric is set.
- Only adjust the timing by adjusting the eccentric (or the stop collar in the case of slip eccentrics) once the valve has been centred. The valve should be just starting to open as the crankpin is at dead centre at both ends of the piston stroke.
- Once one side is timed, then repeat on the other side.
I use oiled brown paper gaskets for steam chest joints, as the gaskets don't have to be replaced each time the valve chest is opened while setting up valve gear.