Removal and inspection
1. Remove the cylinder head cover (see Section Removal and installation of covers of heads of cylinders).
2. Bring the piston of the first cylinder to the TDC position (see Section Bringing the piston of the first cylinder to the top dead center position (TDC)).
3. Remove the ignition distributor (see chapter Engine electrical equipment).
4. Remove the timing belt and balance shaft drive belt (see Sections Removal, condition check and installation of rocker arm assembly and Removal, condition check and installation of camshafts).
5. If necessary, unscrew the camshaft gear mounting bolt to remove it from the trunnion.
Note. To block the shaft from turning, insert a screwdriver through one of the holes in the gear.
6. Remove rocker assembly (see Section Removal and installation of exhaust manifolds). If the camshaft bearing caps are to be removed from the assembly, they must be marked in the order of installation (mark asymmetrically to ensure caps are correctly positioned during installation).
7. Checking the axial play is as follows:
- a) Install the camshaft in the engine and secure it with bearing caps (rocker assembly removed);
- b) Fix the dial gauge on the cylinder head, resting its plunger against the end of the shaft;
- c) Using a large screwdriver as a lever, pull the shaft all the way back and zero the meter, then push the shaft forward and read the instrument reading;
- d) Compare the measurement result with the requirements of the Specifications;
- e) Excessive axial play indicates wear on the camshaft or cylinder head.
8. Remove the camshaft, wipe it dry with a clean rag or paper towel and transfer to a workbench.
9. To check the lateral runout (it would be more correct to entrust the performance of this check to car service specialists):
- a) Lay the camshaft removed from the engine in two V-shaped prisms, then press the plunger of the dial gauge against the neck of the central bearing and measure the amount of runout when the shaft rotates;
- b) Compare the measurement results with the requirements of the Specifications;
- c) In case of excessive runout, the camshaft must be replaced.
10. Check the camshaft bearing washers and the inner surfaces of the bearing caps for scratches and burrs. In case of detection of serious defects, the cylinder head must be replaced with a new or remanufactured one. With calibrated plastic wire (Plastigage set) measure the operating clearances in each of the bearings. Compare the measurement results with the requirements of the Specifications. If the clearance of any of the bearings is out of range, replace the camshaft and/or cylinder head.
Note. Instructions for using the Plastigage kit are given in Sections Installing the crankshaft and checking the operating clearances of the main bearings and Installing connecting rod and piston assemblies and checking the working clearances in the connecting rod bearings of the crankshaft.
11. Assess the degree of wear of the camshaft cams:
- a) Carefully inspect the forming surfaces of the working ledges of all cams, checking them for scratches, scuffs, cavities and signs of uneven wear;
- b) If a defect is found in at least one of the cams, replace the camshaft. Do not forget about the need to identify the causes of wear - check the engine oil for the presence of abrasive particles in it. Check the condition of the oil pump and the patency of all oil flows (wear of the cam lifts is most often associated with oil contamination or a violation of its supply);
- c) Using a micrometer, measure the height of the cams. Compare results of measurements with requirements of Specifications, in case of need replace a camshaft.
12. Check the working surfaces of the rocker arms of the valve drive for signs of wear, scuffs, cavities and other defects.
13. If any of the above defects is detected, check the condition of the engine oil and the serviceability of its supply to the cylinder head. Only after identifying and eliminating the cause of the violation, proceed with the installation of replacement components (head, camshaft or rocker arm assembly).
Installation
1. Thoroughly clean the camshaft, the beds of its bearings in the cylinder head and covers, as well as the rocker arms of the valve drive. Try to completely remove the slightest traces of sludge and dirt. Use only a clean, lint-free cloth to wipe components.
2. Grease cams and bearing necks of a camshaft with special assembly greasing.
Attention! If the shaft is not thoroughly lubricated before installation, serious damage to the bearings and cams can result in the first seconds after the engine is started, before normal oil circulation begins. Carefully lower the camshaft into the cylinder head (its gear should be deployed with a mark "UP" up.
3. Replace rocker assembly (see Section Removal, condition check and installation of rocker arm assembly).
Note. On VTEC models, be sure to clean the oil jet.
4. Correct position of a gear wheel of a camshaft so that its two lateral labels were combined with the top cut of a head of cylinders. Install the timing belt and balance shaft drive belt with related components (see Sections Removal, condition check and installation of cogwheels and a belt of a drive of balancing shafts and Removing, checking the condition and installing the gas distribution belt and timing gears).
5. Further installation is carried out in the reverse order to the dismantling of the components.