Loco Lubrication

[mswift]

Hi
Can anyone give me their thought, experience regarding lubrication for my 5" gauge Britannia.

I have a traditional mechanical lubricator but I also have two Displacement Lubricators which I thought of installing.

I have no doubt that the latter work but how reliable and efficient are they.

I have two but would it be overkill to fit both and could I replace totally the mechanical lubricator?

I really do need a wee bit of advice with this.
Cheers
Mike

[steamer]

Either will work, but I think the displacement units you have are a touch small volume wise, and it would be nice to have a sight glass to see the oil level, otherwise you're guessing on level.

Displacement lubricators, properly built and installed are very reliable, and are dumb as a rock simple.    Getting a mechanical pump "un air bound" can be a royal pain in the 

That said, if you can see the level you can act pre-emptively and fill a mechanical one easily.   the displacement unit no so much unless you can isolate it.

So if you can put in units with sight glasses and isolation, i'd go with the displacement

Otherwise go with the pump.

Dave

[Jo]

Mechanical pumps are great to provide you with that speckled smuts effect all over the face of the driver as they normally deliver too much oil. Too much is better than too little (unless you have to wash their clothes  )

The bee's knees are hydrostatic oilers with glycerine in a sight glass so you can see how much oil is (or is possibly not) flowing into the cylinders 

Edit: Link to an article on Hydrostatic lubricators: https://www.nwmes.org.uk/wp-content/uploads/2019/06/Hydrostatic-Lubricator.pdf

Jo

[john mills]

The mechanical pump can be very reliable and easy to see its working just a trace of oil at exhaust is all that is required often adjusted to give too much with you will get all over you and your passengers.
I have made LBSC design and found to work reliably .
John

[Charles Lamont]

A displacement lubricator with no control valve will empty very quickly.

[mswift]

Wow.....Many thanks for all your advice received yesterday, much appreciated.

I have some thinking to do if I want to mount (if possible) an oil tank below the footplate for a displacement lubricator given the pony truck is under there.
I saw on YouTube a drawing showing such an arrangement which is intended to give a much greater oil storage capacity but no actual video of such an arrangement.

I might take the boiler off the chassis again as its really easy to do at the moment.
Then I will be able to see what I can do within the chassis.

I was thinking of mounting a mechanical lubricator between the frames in front of the smokebox, seems to be enough room but I recall it was very difficult getting an operating rod to the lubricator arm.....will have another look shortly.

Just had a look through my model photos and found one of the cab end showing the pony truck etc......I think this negates any chance of mounting a reservoir in this area.
Included another of some boiler pipework in this area if your interested?

[mswift]

A bit tight but just enough room for the lubricator
Hard part running the link
Sorry for bad photo the lubricator is sat on a piece of wood on the bogie.

[Jo]

I heard someone once asked why you need two hollow tube stays through a boiler:

1, For the blower.
2, For the Hydrostatic oil feed.

 

Jo

[Mike R]

A follow on question if I may - how to size the lubricator or know how much oil is needed?  Is there a rule of thumb based on number of cylinders, and cylinder size, or boiler capacity or ?

Mike

[Jo]

You start on a high oil feed rate and see how much oil is being sprayed up the chimney when you take the engine for a run. You then drop the flow back until you get an oily finger if you rub it round the inside of the chimney but not oil all over the driver's face.

I think I already mentioned: Too much oil is much better than too little.


Size of the oil tank depends on how much running you intend on doing between topping up the oil tank. More cylinders will use more oil.

Jo

[john mills]

If you don't know how big the tank needs to be have a look at some of the existing designs so me have been around for a long time now and
if you look at your local club track you can have a look and see and ask what they are using . lots of designs have quite adequate oil lubricators.
John

[steamer]

If you don't know how big the tank needs to be have a look at some of the existing designs so me have been around for a long time now and
if you look at your local club track you can have a look and see and ask what they are using . lots of designs have quite adequate oil lubricators.
John

Excellent advise John.

If you're running saturated steam, you won't need to much.   It goes up with some superheat  (100F) and then it gets complicated with lots of superheat.     With lots of superheat, you will probably need a mechanical pump and some oil suitable for the steam state.

Dave

[Mike R]

Thanks for the answers, I guess I should have been a bit clearer in the question.  Lets say I'm designing a new steam engine, how is the lubricator sized if its a mechanical displacement type? 
I'm guessing the answer still comes down to experience, whether your own or learning from others and doing the copy cat method of someone else's design for as similar a use case as a first best first guess.
Enough to keep a film on everything when running but not so much that its coming out in quantity like Jo describes as coating the drivers face (or the desk if a stationary model).  I can see that for a model too much is better than not enough as using 50ml vs 100ml for a day isn't going to affect the finances in any meaningful way (except for the excess laundry).

[Alex]

Mike;

The Raritan locomotive was designed with CI pistons, rings and cylinders, and a plug on top of each cylinder to squirt oil in at the end of the day. It's saturated steam, so the condensate provides the lubrication. (it has cylinder drain cocks so you can get the condensate out at the end of the run)

Most of the full sized locomotives I've had the pleasure of working on have had mechanical lubricators, each feed can be adjusted at the lubricator as each pump has an (the lubricator contained numerous pumps, depending on the model) adjustable throw. These were set by the shop, not by us!

However the Shay at the NMST had an interesting hydrostatic lubricator, 4-feed, 3 to the cylinders, one to the air compressor. The on/off valve had a setting for off, compressor only, and running. IIRC, about a drip (floats up) every 4 seconds was set by adjusting the feed valves on the lubricator body.

My model Shay (Kozo, Version 1) has a "hydrostatic" lubricator to the Gamage(?) design, disguised as an air compressor tank on the running board, but as you'll understand from talking, it's never been run, and sits inside a display case. 

My Tich with mechanical lubricator goes through its' tank of oil rapidly, but it's gunmetal cylinders and valves, and O-rings on piston and rods, and the superheater flue has been blocked since the year dot, so it's running saturated, and anyway, the oil ended up on my steaming hat and glasses and tee-shirt and...

We do tend to over oil our little models... at least I do - but once you put the time into building them, you don't want to damage them, so "another drop of oil isn't going to matter", right?

JohnS.