ROD ASSEM. 7J9652 - Caterpillar

The exhaust bypass valve controls the flow of exhaust gas to the turbine wheel in order to maintain the desired boost pressure.
Illustration 1 g00820045
Section view of an exhaust bypass valve
(1) Cap
(2) Locknut
(3) Adjusting screw
(4) Opening for the tube from the turbocharger compressor's outlet
(5) Opening for the breather
(6) Diaphragm
(7) Valve Before the initial engine start-up, remove cap (1). Loosen locknut (2), and turn adjusting screw (3) inward for approximately four turns in order to fully close the exhaust bypass valve. Be careful not to tighten the screw too far.Attach an emissions analyzer to the exhaust elbow.After the engine is started, apply a partial load. Turn the carburetor's load adjusting valve and observe the emissions analyzer. Turn the load adjusting valve until the desired level of exhaust emissions are obtained.
Illustration 2 g00942890
Angle of the throttle plate
Increase the load. Adjust the exhaust bypass valve in order to adjust the boost pressure. Monitor the position of the throttle plate, the desired engine rpm at full load, and the exhaust emissions. Continue to adjust the carburetor's load adjusting valve and the exhaust bypass valve. Make adjustments until the engine is operating at full load with a throttle angle of approximately 70 degrees.When the desired operation is achieved, tighten locknut (2) according to the engine's Specifications. Install cap (1).If you suspect that there is a problem with the exhaust bypass valve, perform an inspection. Make sure that the tube from the turbocharger compressor's outlet is not obstructed. Make sure that the breather is not obstructed.If necessary, remove the exhaust bypass valve for disassembly and inspection.
The exhaust bypass valve cover is under spring compression. To prevent personal injury, use caution when removing the cover.
Inspect diaphragm (6) for damage. Make sure that the valve does not stick. Inspect valve (7) and the valve seat for wear. Repair the exhaust bypass valve or replace the exhaust bypass valve.