The valve guides are so named because they guide the stem of the valve during its motion. By properly locating the stem of the valve, the head and face of the valve are kept in proper relationship to the head. Occasionally, the valve guides will wear, causing poor valve sealing and poor engine performance. If this problem is suspected, check the sideways play of the valve within the guide.
If the play is minimal, it may not be necessary to replace the guides. A competent machine shop can knurl the guides. This process raises a spiral ridge on the inside of the guide, thereby eliminating the wobble and properly locating the valve. This is not a cure-all; it can only be done to correct minimal wear. Severe wear requires replacement of the valve guides.
REMOVAL & INSTALLATION
The use of the correct special tools or their equivalent is REQUIRED for this procedure.Gasoline Engines
See Figures 1 and 2
The valve guides on the B20 and B30 engines can be pressed out with Volvo special tool No. 2818 and a press. New guides are installed with special tool No. 2819 and a press. Substitution tools can be used for either of these operations, however, when installing the new guides, distance A in the illustration must equal 0.689 in. (17.5mm) for all B20 and B30 engines except the B20E and the B20F. For the B20E and B20F, distance A should equal 0.705 in. (18mm).