Replacement of Valve Guides
1. Invert the cylinder head and remove the valve guides using the proper removal drift (see Table 2).
FIGURE 3 - CYLINDER HEAD BASIC BORE GAUGE:
2. Clean the cylinder head bore and check which size valve guide must be inserted (grey-brown or red), refer to steps 3-5. For checking the basic bore, a newly developed bore gauge is available similar to the valve guide bore gauge (see Figure 3, top right corner).
FIGURE 2 - MEASURING POINTS:
3. The cylinder head bore must also be measured at both ends, at axis A and at axis B (see Figure 2).
FIGURE 4 - STANDARD REAMER (14.035 OR 15.035 MM DIAMETER):
4. If the basic bore gauge cannot be inserted to its entire length (8 mm) at any measuring point, the standard (grey-brown) valve guide must be used.
In this case, ream the cylinder head bore with the applicable standard reamer (Figure 4). Refer to Table 2.
5. If the basic bore gauge can be inserted to its entire length (8 mm) at any measuring point, the repair (red) valve guide must be used.
In this case, machine the cylinder head bore with the applicable broach (see Table 2).
Reaming the Cylinder Head Bore, Standard Size, (Standard Reamer)
1. Lubricate the cylinder head bore with cutting oil or kerosene.
2. Keeping the reamer perfectly vertical, insert and start reaming under light pressure (be sure to lubricate with cutting oil or kerosene during this operation).
3. Always turn the reamer in the clockwise direction (never counterclockwise) and pull it out only from the bottom of the bore.
Now the bore has the required size with the specified interference for the standard (grey-brown) valve guide.
CAUTION: Be careful with the reamers and keep them in their protective covering when not in use, in order to prevent the cutting edges from being damaged.
Reaming the Cylinder Head Bore, Repair Size (Broaching Tool)
Before installing, a repair (red) valve guide, machine the cylinder head bore with the applicable broach (diameter: 14.2 or 15.2 mm, see Table 2).
FIGURE 5 - GUIDE SLEEVE:
FIGURE 6:
FIGURE 7:
For this reaming operation a guide sleeve is necessary (Figure 5-7), because the bore for the valve guide and the valve seat ring must be aligned accurately. Refer to Table 1 for the appropriate guide sleeve and broach combination.
Refer to Table 1 for placing proper side (A or B, Figure 5) of guide sleeve into the valve seat insert.
1. Thoroughly clean the cylinder head (especially the inside of the valve seat inserts) using a cylindrical brush (special tool no. 000 589 10 68 00).
2. Prepare the appropriate broach and guide sleeve combination (see Table 1) for the broaching operation.
If necessary, remove chips from the cutting, edges of the broach using a stiff plastic brush or similar tool.
3. Check if the guide sleeve fits exactly in the valve seat insert and is not obstructed by carbon deposits or burrs around the valve seat insert.
4. Apply engine oil to the cutting edges of the broach and to the bores in the guide sleeve and the cylinder head.
5. Push the broach down into the guide sleeve.
IMPORTANT: Be sure that the proper end (A or B) of the guide sleeve has been installed into the valve seat insert.
6. Let the guide sleeve align itself by rotating it in the valve seat insert and by pushing the broach pilot diameter into the cylinder head bore.
7. Tap the broach through the cylinder head bore with a plastic mallet (250 g) and an aluminum punch (length: approximately 130 mm).
8. Clean the cylinder head bore with a cylindrical brush (special tool no. 000 589 10 68 00).