MANIFOLD-FUEL 3447826 - Caterpillar

3406B Truck Engines Equipped With Jacobs BrakeReference: "Remanufactured Cylinder Heads For 3406 Engines " in this issue.A new exhaust valve bridge is used when the Jacobs Brake® is installed on 3406B engines having the newer 7W2200 or the 7W6 Cylinder Heads, not serviced. The former exhaust valve bridge interferes with the new 40 mm 7W5435 Nozzle Adapters used on the above cylinder heads. Effective with 3406B Truck Engines 7FB21132, the new Jacobs 013469 Exhaust Valve Bridge should be used on engines using 40 mm nozzle adapters. The 013469 Exhaust Valve Bridge can be used on both 3406 and 3406B Engines. The former 010831 Exhaust Valve Bridge can only be used with cylinder heads using 1W2950 Nozzle Adapters (55 mm).
The new bridge is similar to the former bridge except for a machined cut which provides clearance for the newer nozzle assembly. The new bridge is identified by the Jacobs part number stamped with ink on the bridge stem. The illustration shows the difference between the two bridges.
Comparing the Jacobs 013469 and 010831 Exhaust Valve Bridges.
Do not grind or modify the former 010831 Bridge to provide clearance for the 40 mm nozzle adapter. Grinding or modifying the bridge in any way may affect the heat treatment, reducing bridge strength. Bridge failure and engine damage may result.