Setting valves

Valve Formulas

From Larry Koehl, Live Steam Magazine, June 1976

The Throw of Eccentric formula, below, applies only to locomotives using Stephenson valve gear.

Larry suggests adding up to 0.002 inches to the Throw of Eccentric value for each pin in the valve gear (including the eccentric, too) because, even when new, there will be lost motion, possibly enough to eliminate the lead.

External Links

• "Steam Cutoff - Part 1 - Fun with Efficiency", PLS Gazette
• "Steam Cutoff - Part 2 - More Fun With Efficiency", PLS Gazette
• "Finding Locomotive Dead Centers", Jeffrey G. Hook
• "Steam Engine Steam Cutoff Explained"
• Locomotive Valves and Valve Gears, with a Special Treatise on Valve Setting
• Allen Models of Michigan catalog contains a write-up on how to set valves for an Stephenson Valve Gear.
• "The Company Notch", DiscoverLiveSteam.com