1.4 VALVES, SPRINGS, GUIDES, INSERTS, SEALS AND ROTATORS When servicing exhaust valves, determine which type of exhaust valve is contained in the engine. If an exhaust valve must be replaced, use the same type that was removed. Do not mix exhaust valve types within an engine. Both exhaust valves are available from service stock for this purpose. Exhaust valve lash settings are affected by the type of exhaust valve that is contained in the engine. The valve lash settings and injector timing height are listed on the valve rocker cover. Refer to section 13.2. Figure 1-67 Minimum Valve Stem Diameter Two types of exhaust valves are used on Series 60 engines.
Pre-1991 model engines use a nickel-based alloy which can be identified by a forged "U" on the combustion face. 1991 model and beyond engines use an austenitic based alloy which can be identified by a forged "H" on the combustion face, and by a machined identification ring above the valve lock groove. See Figure 1-68. The identification ring can be seen from the right side of the engine with rocker cover removed. (Rev. 2005) All information subject to change without notice. 1-82 6SE483 0507 Copyright © 2005 DETROIT DIESEL CORPORATION