Oil starvation

I am having a bad year with squeaking cylinders. Yesterday I acquired a new 5" gauge loco, which was running fine on the rolling road when I went to collect it. As soon as I put it on my track and pushed it along, a horrible squeak from one or even both (inside) cylinders. I assumed oil starvation, and the chimney does seem dry, so I undid the oil supply line and checked everything. Lubricator (mechanical) is working absolutely fine, clacks seem OK. I even pumped a little oil directly into the steam chest. All to no avail This is the third time something like this has happened this year (last year it was injectors - they're now all fine!) Any suggestions on how to get out of this new fine mess?

Well Oliver, The lubricator isn't working against pressure, just atmospheric. Any water under the oil in it? If not I would suspect the piston fit. This is where you need an old car oil pressure gauge

Stan.

Does the level of oil in the lubricator get lower when operating. This would indicate that it is working against steam pressure (unless there is a leak somewhere). Squeak on only one cylinder could indicate a blocked supply line but you said that it is on both cylinders ?. Can you increase the volume of oil from the lubricator ?

Paul

The other thing with this loco is that the valve chest is beneath the cylinders, so any oil injected in would sit on top of the valve cover as far as I can see. (The valve cover being the lowest part of the assembly) I've now become intrigued as to how it would ever mix with the steam and find its way onto the port face. It must have worked once! Thanks for the suggestions so far!

Martin.

Edited By Martin Ashley on 17/10/2020 22:01:52

I have a loco that is 60 years old now, outside cylinder, piston valve and it had a single lubricator feeding both cylinders which appeared to feed as it needed constant topping up. However when I removed the pistons a few years back they had O rings as rings and one side was still in reasonable shape the other completely knackered! All the pipe work was clear but it seemed all the oil was going to the LHS! I made a new lubricator with twin pumps in a single tank with a central divider. I can now monitor that both sides drop at the same rate and be certain both cylinders are definitely getting oil. With your valves being underneath it's best if the oil is introduced close to the steam flow into the steam chest but if you think about the speed of events even if the oil is laid on the valve cover it should still get picked up and carried through.

Paul.

Thanks Paul, appreciate your taking the time to reply. Yes, I've heard that one lubricator supplying both cylinders can be bad news. I would guess particularly with outside cylinders. This loco of mine is of course inside cylinder with the oil feed going into the middle of the front of the chest. She's thirty years old, so I guess it must have worked most of that time! Maybe, as you say, with valves flailing around and steam moving about the oil does somehow get picked up into the flow. I'm now suspecting clacks and will take them apart tomorrow. Bizarre, since this engine is a replacement for one that had outside cylinders, two lubricators and a blow back into one of the lubricators that must have been responsible for a squeak in that engine. Hence my original comment about a bad year for lubricators!

Martin.

Not much to add all well covered but I know on bigger loco's if the piston alignment as set by the crosshead is out it can give funny noises as the piston is rubbing the bore especially when running slow. Occasionally piston rings can make similar noises, strip down and they look fine, reassemble just the same!

Peter