Valve Guide: Testing and Inspection
INSPECTIONValve
(1) Clean valves thoroughly and discard any burned, bent, warped, and cracked valves.
(2) Measure valve stems for wear. Refer to Engine, Specifications.
NOTE: Valve stems are chrome plated and should not be polished.
Valve Guide
(1) Remove carbon and varnish deposits from inside of valve guides with a reliable guide cleaner.
(2) Measure valve stem guide clearance as follows:
(3) Install valve into cylinder head so it is 14 mm (0.551 inch) off the valve seat. A small piece of hose may be used to hold valve in place.
Fig.
(4) Attach Special Tool C-3339, dial indicator to cylinder head and set it at right angle of valve stem being measured (Fig. 106).
(5) Move valve to and from the indicator. Refer to Engine, Specifications for valve guide specifications. If guides are out of specifications, ream to next oversize.
(6) Ream the guides for valves with oversized stems if dial indicator reading is excessive or if the stems are scuffed or scored.
(7) Service valves with oversize stems and over size seals are available in 0.15 mm (0.005 inch) and 0.40 mm (0.015 inch) oversize.
NOTE: Oversize seals must be used with oversize valves.
(8) Select the correct size reamer to accommodate the oversize valve stem. Refer to Valve Guide Oversize Chart.
(9) Slowly turn reamer by hand and clean guide thoroughly before installing new valve. Do not attempt to ream the valve guides from standard directly to 0.40 mm (0.015 inch). Use a step procedure of 0.15 mm (0.005 inch) to 0.40 mm (0.015 inch), so the valve guides may be reamed true in relation to the valve seat. After reaming guides, the seat runout should be measured and resurfaced if necessary. See Refacing Valves and Valve Seats.
NOTE: Replace cylinder head if guide does not clean up with 0.40 mm (0.015 inch) oversize reamer, or if guide is loose in cylinder head.
VALVE GUIDE OVERSIZE CHART