BOLT 8T4908 - Caterpillar

Introduction
This procedure is intended to give information on inspecting the cylinder head. Refer to the Specifications Manual for information on dimensions and specifications for this procedure.Required Tools
Table 1
Required Tools
Part Number Part Description Qty
8S-6691 Cylinder Head Stand Set 1 Inspection Procedure
Remove the cylinder head from the engine.
Remove the water temperature regulator housing.
Inspect the cylinder head for signs of gas or coolant leakage.
Remove the valve springs and valves.
Clean the bottom face of the cylinder head thoroughly. Clean the coolant passages and the lubricating oil passages. Make sure that the contact surfaces of the cylinder head and the cylinder block are clean, smooth, and flat.
Inspect the bottom face of the cylinder head for pitting, corrosion, and cracks. Inspect the area around the valve seat inserts and the holes for the fuel injection nozzles carefully.
Illustration 1 g00842292
Typical example
(1) Cylinder head
(2) 8S-6691 Cylinder Head Stand Set
Put the cylinder head on the 8S-6691 Cylinder Head Stand Set (2).
Test the cylinder head for leaks at a pressure of 200 kPa (29 psi).
Illustration 2 g00924343
Flatness of the cylinder head (typical example)
(A) Side to side
(B) End to end
(C) Diagonal
(D) Distance
Illustration 3 g00860851
Typical example
(3) Straight edge
(4) Feeler gauge
Measure the cylinder head for flatness. Measure the flatness with straight edge (3) and with feeler gauge (4).
Measure the cylinder head from one side to the opposite side (A).
Measure the cylinder head from one end to the opposite end (B).
Measure the cylinder head from one corner to the opposite corner (C).Refer to Specifications, "Cylinder Head" for the requirements of flatness.Resurfacing the Cylinder Head
The bottom face of cylinder head can be resurfaced if any of the following conditions exist:
The bottom face of the cylinder head is not flat within the specifications.
The bottom face of the cylinder head is damaged by pitting, corrosion, or wear.
For engines without valve seat inserts, the valve depths are below the service limit.Note: The thickness of the cylinder head must not be less than 117.20 mm (4.614 inch) after the cylinder head has been machined.If the bottom face of the cylinder head is resurfaced, the recesses in the cylinder head for the valve seat inserts must be machined. Grinding this surface will ensure that no protrusion exists above the bottom face of the cylinder head. Refer to Specifications, "Cylinder Head Valves" for the correct dimensions.