GM 25192555
Exhaust Valve

These tools serve to service and repair the valve: km-571-b(Gage), km-805(Valve Guide Reamer), km-340-1-c(Cutter Set). The necessary service tools include km-571-b (Gage) together with km-805 (Valve Guide Reamer) and km-340-1-c (Cutter Set). The valve stem requires lubrication with a fine-grained paste which can be distributed through regular motion of the valve off its seat by using a commercial valve grinding tool. Use a fine-grained paste to lubricate valve components before examining both valve head contacts and cleaning all components in the Cylinder Head. Examine the valve cone for crater line burns. Note that valve grinding is limited to two cycles before reground and that the valve face maintains a 45-degree angle. Measure the constructed height of both intake and exhaust valves. Use the km-571-b (Gage) combined with a standard inside micrometer to measure valve guide diameters which may currently feature production-installed oversize dimensions. Each valve guide and valve stem end features an oversize service code which links to the valve guide reaming table for determining the correct size, reamer, and production code for each service. Gevante the valve guide by running the km-805 (Valve Guide Reamer) from valve headtop towards the next available size through the upper guide side. Post-production remove the original markings then stamp in the new code. Cut the intake and exhaust valve seats by placing the Cylinder Head on wooden blocks then using km-340-7 from km-340-1-c (Cutter Set) according to the instructions. Ream the valve guide by rotating the km-340-13 (Cutter) at a 44.5-45 degree side and setting both the km-340-13 (Cutter) at a 30-degree upper correction angle and the km-340-26 (Cutter) at a 60-degree lower correction angle. Inspection and cleaning of the Cylinder Head chippings must follow to verify that the valve seat width conforms to these requirements: the specs for valve seat width show 1.17-1.57 mm (0.046-0.062 in) for intake and 1.4-1.8 mm (0.055-0.071 in) for exhaust. Intake 1.17-1.57 mm (0.046-0.062 in) and exhaust 1.4-1.8 mm (0.055-0.071 in).