SENR9977 39 Testing and Adjusting Section 3. Slowly apply air pressure to the wastegate so that the actuator rod moves 1.0 mm (0.039 inch). The air pressure should be within 107 to 117 kPa (15.5 to 17.0 psi). Ensure that the dial indicator returns to zero when the air pressure is released. Repeat the test several times. This will ensure that an accurate reading is obtained. i02254773 Engine Valve Lash - Inspect/Adjust 4. For more information on installing a new turbocharger, contact your Perkins dealer or your Perkins distributor. To prevent possible injury, do not use the starter to turn the flywheel. i01888954 Compression - Test Hot engine components can cause burns.
Allow additional time for the engine to cool before mea- suring valve clearance. The cylinder compression test should only be used in order to compare the cylinders of an engine. If one or more cylinders vary by more than 350 kPa (51 psi), the cylinder and related components may need to be repaired. Valve Lash Setting Valve lash setting Inlet valve ........................... 0.2 mm (0.008 inch) Exhaust valve ................... 0.45 mm (0.018 inch) A compression test should not be the only method which is used to determine the condition of an engine. Other tests should also be conducted in order to determine if the adjustment or the replacement of components is required.
Refer to Systems Operation, “Engine Design” for the location of the cylinder valves. Valve Lash Adjustment If the valve lash requires adjustment several times in a short period of time, excessive wear exists in a different part of the engine. Find the problem and make necessary repairs in order to prevent more damage to the engine. Before the performance of the compression test, make sure that the following conditions exist: The battery is in good condition. The battery is fully charged. Not enough valve lash can be the cause of rapid wear of the camshaft and valve lifters. Not enough valve lash can indicate that the seats for the valves are worn. The starting motor operates correctly.
The valve lash is set correctly. Valves become worn due to the following causes: All fuel injectors are removed. The fuel supply is disconnected. Fuel injectors that operate incorrectly 1. Install a gauge for measuring the cylinder compression in the hole for a fuel injector. Excessive dirt and oil are present on the filters for the inlet air. Incorrect fuel settings on the fuel injection pump. 2. Operate the starting motor in order to turn the engine. Record the maximum pressure which is indicated on the compression gauge. The load capacity of the engine is frequently exceeded. 3. Repeat Steps 1 and 2 for all cylinders.
Too much valve lash can cause broken valve stems, springs, and spring retainers. Too much valve lash can be an indication of the following problems: Worn camshaft and valve lifters Worn rocker arms Bent pushrods