Cylinder Head Assembly: Service and Repair

Fig. 28 Pre-chamber installation:

Fig. 29 Cylinder head tightening sequence:

Fig. 30 Cylinder head bolt identification:

Fig. 31 Cylinder head bolt locations:

If a cylinder head is being removed to correct a head gasket problem on these engines, a few checks should be made to ensure the cause of the condition is corrected. The checks are as follows:
a. Cylinder head warpage. If any cylinder head is warped more than .010 inch, it should be replaced. Resurfacing is not recommended.
b. Cylinder head to cylinder block dowel pin interference. With the head properly positioned on the block, without the head gasket installed, run a .005 inch feeler gauge around the perimeter of the area where the head and block meet. There should be zero clearance, thus ensuring the head is flush with the block and no dowel pin interference exists.
c. Prechamber location. The cylinder head prechambers must not be recessed into the cylinder head or protrude out of the cylinder head by more than .004 inch as this will affect head gasket sealing.
d. Head gasket sealing bead. Ensure the head gasket sealing bead goes around all core holes in the block and head. If the sealing bead crosses a raised, depressed or stamped area, the raised area should be filed and the depressed or stamped area filled with RTV sealer and assembled before the RTV sealer cures.
e. Cylinder head cracks. Minor surface cracks in the cylinder head valve port area between the intake and exhaust ports are considered a normal condition and does not warrant replacement of the heads.
1. Remove intake manifold as outlined previously.
2. Remove valve cover. It may be necessary to remove any interfering accessory brackets.
3. Disconnect glow plug wiring.
4. If right side head is to be removed, remove ground strap from head.
5. Remove rocker arm bolts, pivots, rocker arms and pushrod. Note locations of valve train components so they can be installed in original locations.
6. Remove fuel return lines from injection nozzles.
7. Remove exhaust manifold.
8. Remove engine block drain plug on side of block that cylinder head is being removed.
9. Remove cylinder head bolts, then cylinder head.



10. If necessary to remove pre-chamber, remove glow plug and injection nozzle, then tap out pre-chamber with a suitable drift, Fig. 28.
11. Reverse procedure to install. Do not use any sealing compound on cylinder head gasket. Torque cylinder head bolts in sequence, Fig. 29, to 100 ft. lbs., then 130 ft. lbs.
New head bolts with increased torque capacity were introduced into production during March 1980 and are now available, Fig. 30.
When replacing a cylinder head, it is recommended new head bolts be used if they have not already been installed in the engine. When installing later production model head bolts, be sure to clean and oil the threads. Before installation of the cylinder head ensure bolt holes are tapped deep enough into the block. Blow out any chips or liquid in the bolt holes. Then position cylinder head on cylinder block without the cylinder head gasket. Install bolt and tighten by hand until bolt head contacts the cylinder head. This will indicate that the holes are tapped deep enough into the block, allowing for proper torque. For cylinder head bolt location, refer to Fig. 31.
A new designed head gasket went into production in March 1981, and is available for service replacement. It can be identified by the use of blue print O sealer instead of orange. This gasket is of the slotted and shim design.
No sealer should be used on the gasket during installation. Also the prechamber shield on the cylinder head gasket must be installed toward the cylinder head.