Green Velvet Cylinder Squeak

[Builder01]

The squeak can also come from the slide valves, assuming the engine in question has slide valves. Steve Alley mentioned in his post, about damage on the D valve (slide valve).

David

[Soot n' Cinders]

The squeak can also come from the slide valves, assuming the engine in question has slide valves. Steve Alley mentioned in his post, about damage on the D valve (slide valve).

David

It may be from the valves, but Im not sure. It seemed to line up pretty well with the cylinder movements.

I can't imagine having squeal in iron cylinders with iron rings, as, iron to iron is a very good bearing surface with adequate lubrication. ...what about the gap in your puston rings, could they be to tight, expanding, and being to tight a fit in the cylinder .?

I doubt its the rings as changing oil seems to have taken care of it.

I have built a lot of shays and you need to crank the oil up until the stack looks wet. They take more steam oil to lub things. There should be a wet sheen to the stack top or ring. One customer was using Green velvet and he has steep grades, using the Johnson bar in revers to slow it down. Notice that it would not go down on compression anymore. I took the engine apart and found the D Valve was scored, Showing lack of Lub. Switch to Mobile Steam or and problem went away. I don't think there is enough Tallow in it. Animal fat. Most is 3 % but super heated is up to 5 % tallow. Tallow is like bacon fat or is. If you heat a frying pan on the stove and drop in engine oil it just balls up and bounce's around. But Tallow sticks to the metal. This is where our Lubrication is. At 125 LBS of steam is roughly 350 degrees.
In a three cylinder Shay engine the steam flow is much greater and faster. It carry's more condense water too. Very easy to push out the rod packing with wet cylinders. People say that's what the cylinder cocks are for. But even the full size had this problem, with not getting the cylinders up to temperature. When Cylinders are cold and the steam hits it, it condenses more. The hotter the cylinder is the less it does it. But we want this to make expanded steam.
Not saying green velvet is not good, its just that Shays need more oil. The piston speed is faster than a Rod engine. Tallow is Key.

Steve Alley

Thanks for the info Steve! You're little 1.5" scale shays definitely have the piston speed problem even worse than I do. To get one of those up to track speed, that engine has to be turning insanely fast.

[Soot n' Cinders]

More info from today! I opened up the cylinder heads to find a less than pleasing sight. The inside of the cylinder had almost no oil on it and there were traces of coked oil on the head. My cylinders are getting too hot for the 320 and its cooking rather than oiling.
After finding that I got a returned call from the good folks at the Brennan Oil Company, the distributor of Green Velvet right now. The guy I talked to definitely agreed that 320 was too light of a cylinder oil and the speed of the pistons combined with the temperature of the steam was over heating the oil. He would recommend a 460 grade steam oil but Green Velvet doesnt make one, and he wasnt sure about the 680 grade Sapon-A-Med. However, they do still have contact with Bill Petitjean and he is going to ask him about it tomorrow and get back to me with Bill's recommendation. On the bright side, they price the oils very reasonably. $150 for a 5 gallon bucket shipped.

[Fred_V]

glad to hear you have it running Tristan. How does it go other than the oil issue?
Fred V

[Kimball McGinley]

I tell the new engineers here at work "After you finish a new design that you think you have correct, try it out. Then listen to what the parts have to say; their opinion is much more valuable than yours!"

Your Shay (and Steve) are telling you all that you need to know.

Tough to hear about the crud in the cylinders. After you change oil, maybe then you can change your handle to "Soot n' Slipperiness" ???

[Soot n' Cinders]

I tell the new engineers here at work "After you finish a new design that you think you have correct, try it out. Then listen to what the parts have to say; their opinion is much more valuable than yours!"

Your Shay (and Steve) are telling you all that you need to know.

Tough to hear about the crud in the cylinders. After you change oil, maybe then you can change your handle to "Soot n' Slipperiness" ???

Well everything else is plenty slippery! The PB&J oil hangs around like crazy, as does their soda grease. I’m hoping the grease will become available again as it is a great open gear lube.