Valve guides and valve seats (1) Check each valve for carboning, burning, wear or other defect on head; also check cap end and stem for cracks. Replace the valve if damaged. (2) Check each valve guide for wear. Remember, the guide wears down more rapidly at its both ends than at any other parts. Measure the inside dia- meter of the guide at its ends and a t its middle part in two directions. Measure the outside dia- meter of each valve stem. If the measurement exceeds the repair limit in Table below, replace the valve guide. ( , , , , ) ~: . :~ Wear on valve guide (3) Valve face and valve seat Specifications Unit: mm (in.) Check valve face and valve seat for wear and contact.
If valve face is found excessively worn, reface it by using a valve refacer. To reface the valve, proceed as follows: Specifications Unit: mm (in.) -17 - Item Standard Repair limit Clearance of valve stem in valve guide Intake 0.055 -0.OS5 (0.00217 -0.00335) 0.15 (0.0059) 0.070-0.105 (0.00276-0.00413) 0.20 (0.0079) 18 ± 0.3 (0.709 ± 0.012) Valve stem diameter Intake S -0.045 -0.060 (0315 -0.00177) . -0.00236 -0.10 (-0.0039) Exhaust 8 -0.060 -0.080 (0315 -0.00236) .
-0.00315 -0.15 (-0.0059) Item Angle Sinkage Valve seat Width Nominal value 30° Standard Repair limit Service limit Valve seat n ~ ~~~ ~I~am C:J~ ~ Face i Sinkage O.S (0.031) ±0.2 (±O.OOS) 1.3 (0.051) Width 1.4 (0.055) ±0.14 (±0.005S) 1.6 (0.063) 1 ~ t Valve seat Valve sinkage angle l Counterbore Valve margin Valve margin 1.7 (0.067) Reface up to 1.2 (0.047)