The intake and exhaust valves and seats are finished to set angles. After complete the valve refacing process, examine what remains on the margin. When refacing valve seats, avoid scraping metal from along the head gasket while fixing the valve seat only. Making sure to pick the right size of valve guide pilots guarantees the plate surface is true. With a dial indicator, check that the runout at the valve seat does not go higher than 0.051 mm (0.002 in.) To check if the valve is making contact, use Prussian blue on the valve seat; if the blue stays on the valve face as a dot, everything is fine. For a transfer to the top, lower the seat with a 15-degree stone; for one to the bottom edge, fix the valve seat with a 65-degree stone. Should the angle or width be wrong, the cylinder head must be changed; if they remain correct, the worn or burned valve seats can be repaired. The intake and exhaust seat width should be between 1.50 and 2.00 mm (0.059 - 0.078 in.). Once valve seats or faces are ground, put the valve in the cylinder head and check distance from the tip of the valve to the spring seat. If the valve tip needs adjustment, keep grinding it until it is perfect and then resurface the tip chamfer, if needed, so the seal is not ruined. Lastly, check the spring's installed height after refacing; if the height is too much, add a 0.794 mm (0.0312 in.) spacer to the head counterbore to reduce the spring's height to the correct level.