Inspection

1. Place the cylinder head on two wooden supports, gasket side down..

2. Clean the valve guide bores with a cylindrical brush (special tool no. 000 589 10 68 00) and check the valve guide bores with the applicable newly developed gauge (see Table 2).

FIGURE 1 - VALVE GUIDE BORE GAUGE:

The "no go" end of the gauge has an oversize of +0.22 mm (+220, see Figure 1). If this end of the gauge can be inserted into either end of the valve guide to its entire length (5 mm), the valve guide must be replaced. The valve guide bore gauges are available in diameters of 8, 9, 10 and 11 mm.

NOTE: The 10 mm bore gauge is used for diesel engines and is not covered in this information.

FIGURE 2 - MEASURING POINTS:

Since used valve guides are never completely round, the ends of the gauges are specially shaped (Figure 1, top right corner). This allows an oval bore to be measured. Both ends of the valve guide must be measured with the gauge, at axis A and at axis B (see Figure 2).

3. Replace defective or oversize guides.