Valve Spring: Service and Repair

Fig. 13 Camshaft bearing cap installation:

CAMSHAFT BEARING CAP

1. Align camshaft bearing caps with arrows pointing toward timing chain, Fig. 13. Install caps in numerical order.

Fig. 14 Rocker arm shaft assembly:

ROCKER ARM SHAFT ASSEMBLY

1. Refer to Fig. 14 and install bolts into front bearing caps.
2. Install wave washers, rocker arms, bearing caps and springs in order shown, Fig. 14.
3. Place rocker shaft assembly into position, then rotate camshaft until dowel pin hole is at vertical center line, Fig. 5.
4. Tighten camshaft bearing cap bolts in the following order:
a. No. 3 cap bolts to 85 inch lbs.
b. No. 2 cap bolts to 85 inch lbs.
c. No. 4 cap bolts to 85 inch lbs.
d. Front cap bolts to 85 inch lbs.
e. Rear cap bolts to 85 inch lbs.
5. Repeat steps 4a through 4e, increasing torque to 175 inch lbs.

Fig. 15 Measuring installed valve spring height:

INSTALLED VALVE SPRING HEIGHT

1. Measure installed height of valve spring between spring seat and spring retainer, Fig. 15. Installed height should be 1.590 inch. If height is greater than 1.629 inch, replace spring.

VALVE CLEARANCE ADJUSTMENT

1985 non-turbo and all 1986-88 engines use an auto-lash adjuster located in the rocker arm. No adjustments are required.
1. Check torque on cylinder head bolts before performing valve adjustments.
2. With engine at operating temperature, position piston at TDC on compression stroke.

Fig. 16 Valve clearance adjustment:

3. Loosen valve adjuster locknut, then adjust valve clearance by rotating adjusting screw while measuring with a feeler gauge, Fig. 16.

Fig. 16 Valve clearance adjustment:

4. Valve clearance should be as follows: Intake - .006 inch.; Exhaust - .010 inch.
5. Tighten locknut securely while holding adjusting screw with screwdriver.

JET VALVE SERVICE

1. Install jet valve assembly into cylinder head.
2. Using suitable socket, torque jet valve to 168 inch lbs. Ensure that socket wrench is not tilted with respect to center line of jet valve as damage to the valve stem may result. Check torque on cylinder head bolts before performing jet valve adjustments.
3. With engine at operating temperature, position piston at TDC of compression stroke.

Fig. 17 Jet valve clearance adjustment:

4. Loosen jet valve adjuster locknut, Fig. 17.
5. Proper valve clearance is obtained by rotating adjusting screw while measuring clearance with feeler gauge.
6. Valve clearance should be .010 inch.
7. Tighten locknut securely while holding adjusting screw with screwdriver.