Usage:
3408C (9TD, 9XM, 9ER, 67U) Industrial, 3408C (1LG, 8RG, 1TS, 99U) Marine, 3408C (2BG, 78Z) Generator Set Engines;
3412C (9XF, 8AR, 38S) Industrial, 3412C (3JK, 5RL, 7BL, 60M, 9BR) Marine, 3412C (2WJ, 81Z) Generator Set Engines
Effective with the commercial engines shown in the chart, the valve mechanism groups include valve bridges that do not ride on dowels. See Illustration 1. Formerly, valve bridges that rode on dowels were used. See Illustration 2. At the same time the valve bridges that do not ride on dowels became effective, new longer inlet and exhaust valves became effective. The distance from the top retainer groove to the top of the valve stem is 3.0 mm (.12 in) longer in the new 122-0321 Exhaust Valve and new 122-0322 Inlet Valve than the 115-2367 Exhaust Valve and 115-2368 Inlet Valve. See Illustrations 3 and 4.
NOTE: Install 122-0321 Exhaust Valves or 122-0322 Inlet Valves on engines with a serial number higher than those shown in the chart. For earlier engines, use 115-2367 Exhaust Valves and 115-2368 Inlet Valves.
Illustration 1.
Typical valve mechanism with valve bridges that do not ride dowels. The arrow identifies the valve bridge.
Illustration 2.
Typical valve mechanism with a valve bridge that rides on a dowel. The arrow identifies the valve bridge.
Illustration 3.
122-0321 Exhaust Valve or 122-0322 Inlet Valve. (X) = 15.45 mm (.608 in).
Illustration 4.
115-2367 Exhaust Valve and 115-2368 Inlet Valve. (Y) = 12.45 mm (.490 in).