Valve & Valve Guide

1. Inspect valve for damaged or bent stem, roughness or damage to face, or damage or uneven wear of stem tip, replacing as necessary.
2. Check valve head margin thickness and compare as follows:
a. On SOHC engines, intake valves should be .03-.049 inch (.75-1.25mm).
b. On DOHC engines, intake valve margin thickness should be .054 inch (1.38mm).
c. On SOHC engines, exhaust valve margin thickness should be .047-.071 inch (1.2-1.8mm).
d. On DOHC engines, exhaust valve margin should be .053 inch (1.35mm).
3. Measure valve length. On SOHC engines, minimum length should be 4.776 inches (121.31mm) for intake valve or 4.828 inches (122.63mm) for exhaust valve. On DOHC engines, minimum length should be 4.5165 inches (114.72mm) for intake valves or 4.7299 inches (120.14mm) for exhaust valves.
4. Measure valve stem diameter. On SOHC engines, diameter should be .2744-.2750 inch (6.97-6.985mm) for intake valve or .3159-.3165 inch (8.025-.804mm) for exhaust valve. On DOHC engines, diameter should be .2331-.2356 inch (5.92-5.985mm) for intake valve or .2329-.2354 inch (5.915-5.980mm) for exhaust valve.
5. Measure valve guide inner diameter. On SOHC engines, diameter should be .276-.2768 inch (7.01-7.03mm) for intake valve or .3177-.3185 inch (8.07-8.09mm) for exhaust valve. On DOHC engines, diameter should be .2366-.2374 inch (6.01-6.03mm) for intake valve and exhaust valves.
6. Measure valve stem to guide clearance, which should be .0010-.0024 inch (.025-.06mm) for intake valve or .0012-.0026 inch (.030-.065mm) for exhaust valve. If clearance exceeds .0079 inch (.2mm), replace valve and/or valve guide.

Fig. 18 Checking Valve Guide Protrusion:

7. On SOHC engines, replace valve guide as follows:
a. Gradually heat cylinder head in water to 190°F.
b. Using tool 490249010A or equivalent, remove valve guide from side opposite combustion chamber, then remove valve guide clip.
c. Install clip onto valve guide and, with cylinder head heated to 190°F, tap valve guide in from side opposite combustion chamber until clip contacts cylinder head.
d. Check that height A on 1989-91 models shown in Fig. 18, is .52-.543 inch (13.2-13.8mm) for intake valve or .772-.795 inch (19.6-20.2mm) for exhaust valve. On 1992 models height A should be 0.717-0.740 inch. For 1992 models the shapes of the intake and exhaust valve guides are different, use the exhaust valve guide on both sides as a replacement.

Fig. 19 Valve Guide Protrusion Measuring Tool Assembly. DOHC Engine:

8. On DOHC engines, replace valve guide as follows:
a. Using punch tool No. 49 B012 005 or equivalent and a hammer, remove valve guide from side of opposite combustion chamber.
b. Assemble special tools as shown in Fig. 19, so that depth on 1989-91 models is .701-.724 inch and 0.716-0.740 inch on 1992 models.
c. Tap valve guide in from side opposite combustion chamber until tool contacts cylinder head.
d. Ensure valve guide projection is within specification.