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Stanley slide valve differences
Posted by: SSsssteamer (IP Logged)
Date: November 12, 2005 03:18PM
<HTML> A well known Stanley engine rebuilder wrote: "We have both spent hours over the phone measuring valve faces and blocks in the past with no answers and lots of different dimensions. However, we do know that the short end of the valve goes on the head end not on the crank end. This probably has something to do with the fact that if you look at the piston action you will find that the piston is at the middle of it's stroke when the connecting rod is at right angles with a line drawn from the counterweight stub to the crank centerline and not when that line is perpendicular to the frame rods. As a result it takes a longer portion of the crankshaft rotation for the piston to travel from the middle of the cylinder to the bottom than it does from the middle to the top. Weird, huh? More food for thought! We know if you make the valve faces even, the engine will run poorly. A friend did this with a new block from John Goold on his 30hp car that ran horribly. "Proper" valves were made with uneven face widths and it runs great now. "
In making new valves for our 30 hp Mt Wagon, the slide valves' faces were of different widths. The front face was 0.050" narrower than the rear face. In checking a couple of sets of 20 hp valves, the same differences were noted. So I made new valves with these same differences and reinstalled them. The 10 hp type 6 engine has equal sized faces as does several other early engines. I was told that the unequaled width valve face differences were found mostly on the model 735 engines. The valve eccentrics are ground differently to require these different valve face widths. By model 740, I was told that the slide valves were again symmetrical again. Which all engines require the different sized slide valve faces? I have been building up engines from missmatched parts. Is there an easy quick way to determine which crankshafts require which valves?</HTML>
In making new valves for our 30 hp Mt Wagon, the slide valves' faces were of different widths. The front face was 0.050" narrower than the rear face. In checking a couple of sets of 20 hp valves, the same differences were noted. So I made new valves with these same differences and reinstalled them. The 10 hp type 6 engine has equal sized faces as does several other early engines. I was told that the unequaled width valve face differences were found mostly on the model 735 engines. The valve eccentrics are ground differently to require these different valve face widths. By model 740, I was told that the slide valves were again symmetrical again. Which all engines require the different sized slide valve faces? I have been building up engines from missmatched parts. Is there an easy quick way to determine which crankshafts require which valves?</HTML>
Re: Stanley slide valve differences
Posted by: Rolly (IP Logged)
Date: November 12, 2005 04:37PM
<HTML>Any good design of outside admission valves using Stephenson links for the valve operation will have a wider face on the button end of the valve. Toward the crank end.
Two events you always want to be equal at both ends of the cylinder are lead and compression. It you do the geometry, laying out valve gear with Stephenson links you always get a wider face on the crank end of the valve.</HTML>
Rolly
Two events you always want to be equal at both ends of the cylinder are lead and compression. It you do the geometry, laying out valve gear with Stephenson links you always get a wider face on the crank end of the valve.</HTML>
Rolly
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