Green Velvet Cylinder Squeak

This forum is dedicated to the Live Steam Hobbyist Community.

Moderators: Harold_V, WJH, cbrew

Soot n' Cinders
Posts: 701
Joined: Wed Jun 27, 2012 5:24 pm
Location: Marietta, Georgia

Green Velvet Cylinder Squeak

Post by Soot n' Cinders » Tue Sep 25, 2018 9:16 am

After doing some research, Im wondering if Im doing something wrong. I tried some Green Velvet Sapon-A-Max 320 in my shay the other day and my cylinders started to squeak and just generally not sounding happy even after spinning to lubricator ratchet by hand a couple turns. I know a lot of people like the Green Velvet oil and use it successfully but I didnt have much luck with it.
My shay pops at 125psi and has 2in bore cylinders. The lubricator is an American Model Engineering twin ram pump run off the rear reverse eccentric that has a total throw of 0.5". The rod is set in the inner hole of the arm, giving about 3 clicks per revolution. When I borrowed some Mobil Super 600, the squeak went away. Is there something off with my setup or can I just not use Sapon-A-Max 320?
I know the Super 600 is an ISO 460 grade oil, but Green Velvet does not make a 460 steam oil. So has anybody tried using the Sapon-A-Med 680 in our little engines?
-Tristan

Projects
-2.5" scale Class A 20 Ton Shay

User avatar
Builder01
Posts: 454
Joined: Mon May 18, 2015 5:26 am
Location: Erie, PA

Re: Green Velvet Cylinder Squeak

Post by Builder01 » Tue Sep 25, 2018 11:19 am

I had a similar situation happen to me using "generic" cylinder oil. I was running with one click on my mechanical lubricator and getting occasional squeaking. When I increased it to 2 clicks, no more squeak! My cylinders are much smaller than yours and need probably much less oil. At any rate, the solution was more oil. I have yet to try Green Velvet.

David

User avatar
cbrew
Posts: 2726
Joined: Sat Jan 04, 2003 12:17 pm
Location: Vancouver Wa

Re: Green Velvet Cylinder Squeak

Post by cbrew » Tue Sep 25, 2018 11:35 am

Tristan, is this the first time you have any real time in steam?
If it is not live steam. its not worth it.

Soot n' Cinders
Posts: 701
Joined: Wed Jun 27, 2012 5:24 pm
Location: Marietta, Georgia

Re: Green Velvet Cylinder Squeak

Post by Soot n' Cinders » Tue Sep 25, 2018 12:03 pm

Yes and no. The shay was just fired up a week and a half ago, but the green velvet test wasn’t done till several days into running. It had been running on what I think was Mobil Super 600 and when my can ran out I tried the green velvet. I ran about 5 trips on the green velvet with the squeaking getting more persistent. The next day I refilled the lubricator with some heavier steam oil, may have been Mobil 600 or Green Velvet 680 but I don’t remember, and the problem went away after the first trip with that.
-Tristan

Projects
-2.5" scale Class A 20 Ton Shay

User avatar
cbrew
Posts: 2726
Joined: Sat Jan 04, 2003 12:17 pm
Location: Vancouver Wa

Re: Green Velvet Cylinder Squeak

Post by cbrew » Tue Sep 25, 2018 12:21 pm

ok, first though was a tight fit between moving parts but your testing shows other wise.

is the squeaking coming from the packing? what type of packing did you go with? ( i am asking for my info )
If it is not live steam. its not worth it.

Soot n' Cinders
Posts: 701
Joined: Wed Jun 27, 2012 5:24 pm
Location: Marietta, Georgia

Re: Green Velvet Cylinder Squeak

Post by Soot n' Cinders » Tue Sep 25, 2018 12:28 pm

I think the squeak is the rings on the cylinder, which is iron on iron. The packing is square graphite yarn from McMaster-Carr.

I’m wondering if the speed of the engine is having an effect. My engine has to turn 100rpm per 1mph, more than double that of something like an Allen engine.
-Tristan

Projects
-2.5" scale Class A 20 Ton Shay

James Powell
Posts: 312
Joined: Fri Oct 28, 2011 10:42 pm

Re: Green Velvet Cylinder Squeak

Post by James Powell » Tue Sep 25, 2018 12:38 pm

Probably thickness of the oil. Is the shay superheated?

My Caribou doesn't like TK460, but is happy with what I assume is 1200w (it's Gulf, so was 20 years old 20 years ago...). Superheated, and tight piston valves. With the 460, it tends to seize up at speed. It too suffers from small wheels and fast piston speeds. (8.5 mph out of 3" wheels...mind, it is a rod engine)

James

Soot n' Cinders
Posts: 701
Joined: Wed Jun 27, 2012 5:24 pm
Location: Marietta, Georgia

Re: Green Velvet Cylinder Squeak

Post by Soot n' Cinders » Tue Sep 25, 2018 12:51 pm

The shay is not superheated, not that superheat in this scal is true superheat anyway.
I have 6” drivers and a 2:1 gear ratio, so that’s the equivalent of a rod engine with 3” drivers. Doing the math, for 3mph my pistons are moving almost 2ft per second on average. I don’t know what the peak speed of the piston would be during the rotation, but it’s quick
-Tristan

Projects
-2.5" scale Class A 20 Ton Shay

User avatar
cbrew
Posts: 2726
Joined: Sat Jan 04, 2003 12:17 pm
Location: Vancouver Wa

Re: Green Velvet Cylinder Squeak

Post by cbrew » Tue Sep 25, 2018 12:56 pm

Soot n' Cinders wrote:
Tue Sep 25, 2018 12:28 pm
I think the squeak is the rings on the cylinder, which is iron on iron. The packing is square graphite yarn from McMaster-Carr.

I’m wondering if the speed of the engine is having an effect. My engine has to turn 100rpm per 1mph, more than double that of something like an Allen engine.
hmm, when my lubricator quit at Train mountain one time, my Allen started to squeak at the packing. once i wet the packing with oil the squeak went away. I pumped a couple shots of oil into each cylinder and that allowed me to get the loco back to top of the hill

being a new engine, I would crank up the oil output and see if that helps. or just stay with the thicker oil
If it is not live steam. its not worth it.

Steve Alley
Posts: 185
Joined: Thu Dec 20, 2012 12:30 am

Re: Green Velvet Cylinder Squeak

Post by Steve Alley » Tue Sep 25, 2018 2:06 pm

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

User avatar
Builder01
Posts: 454
Joined: Mon May 18, 2015 5:26 am
Location: Erie, PA

Re: Green Velvet Cylinder Squeak

Post by Builder01 » Tue Sep 25, 2018 3:28 pm

As I mentioned in my first post, when I increased the lubrication delivery, the squeak went away. The condition at the stack went from a dry and crumbly residue, to what is now a wet ring.

David

hoppercar
Posts: 48
Joined: Sun Jul 22, 2018 4:09 pm

Re: Green Velvet Cylinder Squeak

Post by hoppercar » Tue Sep 25, 2018 4:38 pm

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 .?

Post Reply