REMOVAL & INSTALLATION
B20 and B30 Engines
- Remove the retaining screws and the valve cover and gasket.
- Remove the rocker shaft-to-cylinder head bolts and lift out the shaft and rocker arms as a unit.
- Lift out the pushrods, keeping them in order (an upside down shoebox with numbered holes makes an excellent holder) and check them for straightness by rolling them on a flat surface. Replace any bent pushrods.
- Inspect the rocker shaft arms. If the shaft and rockers are coated with baked-on sludge, oil may not be reaching them. Clean out the oil feed holes in the rocker shaft with 0.020 in. (0.5mm) wire (piano wire). If the clearance between the rocker arms and shaft exceeds 0.004 in. (0.1mm), the rocker arm needs to be rebushed. The rocker arm bushings are press fitted, and are removed with a drift. When pressing a new bushing, make sure that the oil hole in the bushing aligns with the hole in the arm.
- Position the pushrods on their respective lifters. Install the rocker shaft and arm assembly on the head, and install the retaining bolts. Use a three step tightening procedure. Working from front to rear, tighten all the retaining bolts to 10 ft. lbs. (14 Nm). Following the same pattern, tighten all the bolts to 15 ft. lbs. (20 Nm), then make a final pass tightening all the bolts to 20 ft. lbs. (27 Nm).
- Check to see that valve lash has remained within specifications. Adjust valve lash, if necessary, as outlined in General Information & Maintenance .
- Install the valve cover with a new gasket, and tighten the valve cover retaining screws. Do not overtighten the valve cover bolts.
See Figures 1 and 2
- Disconnect the negative battery cable.
- Disengage the ignition system connector located on the right shock tower.
- Using a 5mm Allen wrench, disconnect the control pressure regulator and lay the regulator on the intake manifold.
- Remove the oil filler cap and hoses.
- Remove the vacuum pump (left rear of engine); on B27, remove air pump if so equipped. Remove the air inlet duct running to the top center of the motor.
- On air conditioned models, remove the AC compressor. On B27s, remove the rear bracket. DO NOT loosen or remove any hoses at the compressor; simply remove the entire unit and use wire to tie it out of the way. Do not allow the compressor to hang by its hoses.
- Loosen the valve cover bolts and remove the valve covers.
- The rocker arm bolts double as cylinder head bolts. When loosening, follow the cylinder head bolt tightening sequence diagram. If removing both rocker shafts, mark them left and right.
Do not jar or strike the head while rockers and bolts are out, as the cylinder liner O-rings may break. If this happens, the engine requires a full tear-down to clean coolant out of crankcase and install new seals.
- To install, place the rocker shaft in position on the proper side of the engine. Install the bolts finger-tight, then use a three step tightening procedure. Tighten the bolts in the order shown in the illustration.
- Reinstall valve covers with new gaskets. Replace all components in reverse order, remembering to adjust the belts. When reinstalling the vacuum pump, use a new gasket and make sure the pump contacts the top side of the camshaft.