Cylinder Head Assembly: Service and Repair

TJ
:

REMOVAL
- Remove fuel injectors.
- Remove drive belt.

NOTE Mark running direction of the drive belt before removing. This orientation MUST be maintained when reinstalling.

- Remove intake manifold.




- Remove cylinder head bolts in reverse order of the tightening sequence.
- Remove throttle cable.
- Disconnect exhaust.

DISTORTION, CHECKING

NOTE: Cylinder head should be clean and free of gasket material before performing this check.




- Use straight edge US 1030 and feeler gage to check for distortion.
- Maximum permissible distortion is 0.1 mm (0.004 in).

REFACING

- Measure distance between cylinder head bolts surface and lower edge of cylinder head.
- Minimum dimension 118.1 mm (4.65 in).

INSTALLING

NOTE: Prior to installing cylinder head be sure that crankshaft is at TDC and that camshaft markings are aligned.

- Install cylinder head gasket on locating pins with word OBEN (and/or part number) facing cylinder head.
- Install cylinder head, insert head bolts finger tight.



- Tighten cylinder head bolts in three step sequence as follows (engine cold):

Step I = 40 Nm (29 ft Ib)
Step II = 60 Nm (44 ft Ib)
Step III = 1/2 additional turn (180°) to each bolt in one movement (two 90° turns are permissible).

NOTE: It is not necessary to re-tighten cylinder head bolts during scheduled maintenance or after performing repairs.

- Install drive belt.

- Adjust accelerator cable by inserting movable clip into cable adjustment slots so that with pedal fully extended to the floor; full throtttle is just reached.