GM 55558728
Exhaust Valve

Performing valve service and repair requires using three essential tools namely km-571-b (Gage), km-805 (Valve Guide Reamer), and km-340-1-c (Cutter Set). Start by putting a fine-grained paste on the valve stem and operating the valve against a grinding tool to spread the lubricant around. Look at the valve contact marks on both valve head and Cylinder Head components while cleaning all valve-related parts. Check if the valve cone shows burn marks from grinding and know that you can grind the valve two times before the stem part and the 45-degree angle needs to be used. Check the distance between intake and exhaust valves during their assembly. Check valve guide dimension with the km-571-b (Gage) and regular micrometer while noting about factory-installed valve oversizes. Each production value has an oversize service code on both valve guide and stem ends along with specific cutting tools details in the valve guide reaming table. Use the km-805 valve guide reamer at the Cylinder Head top to reach the next available size and replace both the production and service codes. Set the Cylinder Head on two wooden blocks and use the km-340-7 (Cutter) from the km-340-1-c (Cutter Set) to cut the valve seats where intake and exhaust meet. For this task use km-340-13 (Cutter) to cut 44.5-45 degree side (b), 30 degree side (a) with km-340-13 (Cutter), and 60 degree side (c) with km-340-26 (Cutter). Check for chippings in the Cylinder Head while inspecting that the valve seat opening fits these size ranges: intake 1.17-1.57 mm (0.046-0.062 in) and exhaust 1.4-1.8 mm (0.055-0.071 in).