08/01/2024
Valve guides for EMD available for purchase.
The new close tolerance nitrided valve guide, part numbers 8310840/40082769, is now available exclusively through the Parts Department at a 16% discount on standard sizes and a 66% reduction for oversize. This price reduction has been enabled by the complete overhaul of the valve guide manufacturing process, which now includes a suite of new automated machines. Additionally, a novel gun reaming technique—akin to the method used for boring rifle barrels—has been introduced, offering enhanced dimensional stability and control for improved tolerances and extended service life, superseding the old single-point boring tool method. For optimal wear compatibility between the valve stem and guide, the stem must be harder than the guide; otherwise, the longevity of both components could be significantly compromised. The nitriding process applied to the valve guides after precision machining imparts a dual hardness to the surface. Carbon and nitrogen synergistically create a thin, tough, ductile, and abrasion-resistant outer layer, while a deeper layer, enriched with nitrogen, provides excellent anti-galling characteristics and minimizes the risk of bell mouthing. Beneath the secondary hardness layer lies a fine-grained, pearlitic iron matrix that ensures the valve guide's stability in demanding conditions. The nitriding finish not only enhances lubricant retention for reduced wear between the valve stem and guide but also contributes to the component's longevity. The standard valve guide is numbered 8310840, and the oversize variant is 8338304.
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