UENR0623-02 71 Air Inlet and Exhaust System 7. If an engine valve lash is found in any position, examine the valve mechanism components for excessive wear or damage. Examine the hydraulic lash adjusters for damage. 4. Service wear occurs on an engine which has been in operation. If the valve depth below the cylinder head face on a used engine exceeds the specification for service wear, the following components must be replaced. i04215789 Valve Depth - Inspect Valves Valve inserts Table 8 For the wear limits for the inlet valves and exhaust valves, refer to Specifications, “Cylinder Head”. 5. Check each valve for cracks. Check the stems of the valves for wear.
Ensure that the valves are the correct fit in the valve guides. Refer to Systems Operation, Testing and Adjusting, “Valve Guide - Inspect” for the procedure to inspect the valve guides. 6. Check the load on the valve springs. Refer to Specifications, “Cylinder Head Valves” for the correct lengths and specifications for the valve springs. i04483849 Valve Guide - Inspect Perform this test in order to determine if a valve guide should be replaced. Illustration 61 g01201916 Typical example 1. Ensure that the face of the valves are clean. Ensure that the bottom face of the cylinder head is clean. Ensure that the cylinder head is not distorted.
Refer to Systems Operation, Testing and Adjusting, “Cylinder Head - Inspect” for the procedure to measure flatness of the cylinder head. Illustration 62 g00314806 Measure the radial movement of the valve in the valve guide. (1) Valve guide (2) Radial movement of the valve in the valve guide (3) Valve stem (4) Dial indicator (5) Valve head 2. Use the Tooling (A) to check the depths of the inlet valves and the exhaust valves below the face of the cylinder head. Use Tooling (B) to zero Tooling (A). 1. Place a new valve in the valve guide. 3. For the minimum and maximum limits for a new engine for the inlet valves and the exhaust valves, refer to Specifications, “Cylinder Head”. 2.
Place a dial indicator with a magnetic base on the face of the cylinder head. Required Tools Tool Part Number Part Description Qty A 21825617 Dial gauge 1 B 21825496 Dial gauge holder 1