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topct
10-01-2010, 03:33 PM
Need to know how tight the sliding valve needs to be. The engine needs a gasket under the valves cover and when I took the cover off noticed that the valve is loose on its operating rod. Is there some kind of rule of thumb as to how tight it should be against the ports?

Also, for running it on compressed air for short demos, what kind of oil can I squirt into it?

This is an Orr & Sembower. It stands about 40 some inches tall and it does run now. It's just got this horrible air leak out of the valve chest and with the valve being loose my little compressor cant get more than about 30 revolutions out of it before I run out of air.

http://img.photobucket.com/albums/v78/topct/IMG_0157.jpg

small.planes
10-01-2010, 03:56 PM
If its a 'normal' slide valve then it should be able to float. The pressure different between inlet and exhaust (usually the center port) holds the valve against the ports, but allows any condensate to force the valve off its seat without hydraulicing the engine.

Google slide valve, you'll find illustrations Im sure.


Dave

tdmidget
10-01-2010, 04:00 PM
For lubrication an in-line oiler and airtool oil should be fine. If you run it on steam then you will need a steam cylinder oil.

Liger Zero
10-01-2010, 04:39 PM
Is that an actual engine or a functioning scale model?

Either way, very cool.

JCHannum
10-01-2010, 05:25 PM
The pressure differential does hold the slide valve in place, but the valve face and valve chest surfaces should be a very close fit, lapped if possible. It might help to grease the surfaces initially to help in obtaining a seal.

That is an attractive engine, what is the bore & stroke? How large is your air compressor?

Rich Carlstedt
10-01-2010, 11:27 PM
What is that contrivance on the exhaust Pipe..looks like a check valve???
As Jim said , the pressure will keep the valve against the valve face ----except if the exhaust is restricted, in which case the exhaust pressure may lift off the valve from the face.This occurs especially if timing is late
On a Horizontal engine, gravity helps, but on a vertical engine, only pressure differential of supply and exhaust keep the faces intact
For leak control, lapping in the valve works wonders

Nice engine

Rich

aviatakl
10-02-2010, 12:51 AM
Yes, the pressure of steam holds the 'D' valve against the steam port of the cylinder. The valve should be 'tight' between the top and bottom nuts that hold the valve in the correct position. The valve generally has a slightly larger hole or slot that the valve rod is connected to the valve. This allows the valve to move and be held to the port face by the pressure of the steam.

Your engine is a single direction type. That is to say it would probably need a 'kick' by hand in the direction you want it to run. This is indicated by the single valve rod and one Eccentric.

I also notice that you are applying the 'air' for motive force via the top of the valve chest. Is there not a steam entry port on the side of the valve chest?

You have adjustment for the 'cut off' of the valve position via the locking nuts at the top of the eccentric rod, and at the bottom end of the valve rod. Normally, a small engine like this has no overlap or cutoff set to the valve which is set to the middle of the valve stroke with the piston at extreme end position of stroke.

Jim O'Donnell

topct
10-02-2010, 08:48 AM
Thanks for the replies.

I will leave the valve alone to float on the ports. The engine does run and it should get better just by sealing up the chest. I have some air tool oil that I can squirt into it for the short demo runs.

The story I have gotten on this engine is that it came from one of the areas gold mines. It has been in storage/display at the local fair grounds for several years. The steam inlet port at the top of the chest was plugged to close it up and the exhaust pipe had a cap on it when it came here. I will guess that all the original piping was removed and to attempt to make it look a little more complete someone has just grabbed some fittings and screwed them on. The "T" on the exhaust just has a plug in it.

Whoever saved this thing from the scrap yard did a good job of oiling and greasing everything and it seems to be in very good condition. I would guess this one never was used or stored outside. There is not single sign of rust anywhere I can see.

I think whats really amazing is that without doing anything to it other than to check for anything binding and removing the cap from the exhaust, screwing a air hose barb and applying air the thing made its first chuff after sitting for so long. Grabbing the larger flywheel and giving it a good pull it made about two revs before all my air leaked out. All I have for air is a 3 1/2 horse 30 gallon compressor so letting it pump up again and reattaching the air hose I quickly gave the wheel a pull and the engine then ran for several revolutions. I am hoping that a gasket under the valves cover to keep my limited air from escaping will let it run longer.

I can see the attraction to these things standing next to it while it chuffs away. It is sitting on a concrete floor in my storage shed and even as small as it is you can feel what feels like a minor earthquake in your feet as it runs.

gary350
10-02-2010, 09:22 AM
The engine you have may have been restored that is probably why it is in such good condition. I had an engine almost identical to yours, sold it to a guy in Memphis about 10 years ago. Your engine probably has a oil pump in the bottom and an oil tank. Oil pumps up to the top and rains down on the moving parts inside the crankcase. Your engine should run for display on about 5 psi air pressure and turn about 10 RMPs at that pressure.

I built a steam boiler for my engine it was 4.9 gallons. As long as the boiler is less than 5 gallons you are not required by law to have it inspected and tested. This boiler ran my 4x4 steam engine at about 20 RPMs on about 5 psi steam pressure all day as long as I kept it full of water and the fire going. I could build up 120 psi steam pressure and run the engine at 500 RPMs for about 30 seconds.

topct
10-02-2010, 10:25 AM
The engine you have may have been restored that is probably why it is in such good condition. I had an engine almost identical to yours, sold it to a guy in Memphis about 10 years ago. Your engine probably has a oil pump in the bottom and an oil tank. Oil pumps up to the top and rains down on the moving parts inside the crankcase. Your engine should run for display on about 5 psi air pressure and turn about 10 RMPs at that pressure.

I think it is more "well preserved" rather than restored. There is no oil pump in it. There are two oil cups on the connecting rod, one on top and another at the crank end. The crankshaft bearings have a cup on the top of the caps with a large hole that goes down into the bearing. These have been packed with grease. I'm guessing that isn't correct but it has kept any moisture out and depending on how much more work the owner wants me to do I think it will be alright for now.

If anyone happens to know what actually was used to lubricate the crank bearings on this series of engines I can pass that on to the owner and let him decide what he wants to do.

oil mac
10-02-2010, 11:21 AM
Gene,
I notice inboard from the large flywheel on the engine, is a little flanged pulley, I would guess that at some stage in the engines early life, it likely had a drive from this pulley up to a Pickering governor mounted on the inlet steam pipe
It is a nicely proportioned little engine from the photo simple &reliable, It is nice it has survived & in good condition
At the present, i have a single cylinder horizontal in for repairs, pretty ancient old thing, I would reckon a large model cylinder approx 3"stroke x 1&1/4" bore, fairly poor state, It has a badly bent valve rod, When i reset the tiny slide valve I will ensure a "light friction" between the valve rod collars-- no shake & a little lift with my fingers, I certainly do not want another bent rod or burst cylinder cover Like you folks, it will get a run on air to test all is well.
Dan.

topct
10-02-2010, 11:43 AM
Gene,
I notice inboard from the large flywheel on the engine, is a little flanged pulley, I would guess that at some stage in the engines early life, it likely had a drive from this pulley up to a Pickering governor mounted on the inlet steam pipe
It is a nicely proportioned little engine from the photo simple &reliable, It is nice it has survived & in good condition Dan.

Thanks for that bit of info. I was wondering what that pulley was for and it makes perfect sense. They would want a constant speed out of it for whatever the were driving.

I probably went along with an inline oiler and various other small parts. I think it's only luck that the two drip oilers are still on the side of it.

barts
10-02-2010, 12:03 PM
If anyone happens to know what actually was used to lubricate the crank bearings on this series of engines I can pass that on to the owner and let him decide what he wants to do.

You can use 600W steam cylinder oil on those bearings w/o any problems... alternatively, heavy way oil works well too; it has tackifiers that help keep the oil in place. If the bearings are very worn, grease may work better for occasional demos as it's less messy.

- Bart