Contents: Removal ⇊ Installation ⇊
Caution! Wait until the engine has completely cooled down before starting work.
Removal
1. Bring the piston of the first cylinder to the TDC position of the end of the compression stroke (see Section Bringing the piston of the first cylinder to the top dead center (TDC) position).
2. Disconnect the negative cable from the battery.
Warning! If the car stereo system is equipped with a security code, make sure you have the correct combination to activate the audio system before disconnecting the battery!
3. Drain the cooling system and remove the spark plugs (see Chapter Settings and ongoing maintenance).
4. Unscrew the bolts securing the intake manifold mounting bracket and the bolts securing the exhaust manifold flange to the exhaust manifold (see Sections Removal and installation the intake manifold and Removal and installation the exhaust manifold).
Note: The head can be removed together with the pipeline and exhaust manifold, however the procedure is significantly simplified (due to the reduction in the mass and size characteristics of the unit) if the mentioned elements are first dismantled.
5. Remove the air intake pipe (see Section Removal and installation the intake manifold) and the cylinder head cover (see Section Removal and installation the cylinder head cover). Remove the ignition distributor assembly with the cover and high-voltage wires (see Chapter Engine electrical equipment).
6. Remove the steering pump (see Chapter Suspension and steering).
7. Remove the timing belt (see Section Removal, condition check and installation of the timing belt and timing drive gears), rocker arm assembly (see Section Removal, condition check and installation of rocker arm assembly) and the camshaft (see Section Removal, condition check and installation of the camshaft).
8. Loosen the clamp and disconnect the water hose connected to the cylinder head directly under the ignition distributor.
9. Acting in the reverse order to that shown in the illustration, in several steps (1/4 turn per approach) loosen the head mounting bolts enough to make it possible to unscrew them manually. Try to remember the installation position of each of the mounting bolts - during assembly they must be screwed in strictly in their original places.
10. Remove the cylinder head from the engine. If the head does not separate from the block, you can use a lever, which should be inserted between the steering pump bracket and the block (under no circumstances pry the head under the mating surface). Place the head removed from the engine on a couple of wooden blocks to avoid damaging the gasket surfaces.
10. A description of the procedures for disassembling the head and checking the condition of its internal components is given in Part General and major engine repairs of this Chapter. At this stage, evaluate only the flatness of the mating surface.
11. Assess the condition of the threaded portion of the head mounting bolts by measuring their diameter at two points with a micrometer. If any of the bolts show signs of wear, replace the entire set.
Installation
1. The mating surfaces of the cylinder head and block must be absolutely clean and dry.
2. Carefully clean the mating surfaces of the head and cylinder block. After scraping off the remaining gasket material and carbon deposits, wipe the surfaces with a rag soaked in acetone. The presence of old gasket material on the mating surfaces when installing the head may lead to a violation of the seal of the gasket fit and, as a result, the development of leaks. When processing the block, plug the cylinder holes with a rag to prevent small debris and various foreign objects from getting into them (as a last resort, thoroughly vacuum the cylinders). Since the head and cylinder block are made of a soft aluminum alloy, act with special care, trying not to leave scratches and burrs on the mating surfaces (use only copper or plastic tools to scrape off deposits).
3. Check the mating surfaces of the head and block for deep scratches, burrs and other damage. Minor defects can be eliminated with fine-grained sandpaper. In more serious cases, the only alternative is to regrind or replace the components. Use a tap of the appropriate size to run the threaded holes for the head mounting bolts. Clamping the bolts in a vice by the head one by one, go over their threads with a die - the presence of old sealant, dirt and corrosion products in the threads leads to a discrepancy between the actual tightening force of the fastener and the readings of the torque wrench indicator. On F23A5 series engines (without VTEC), remove the oil sprayer from the block, clean it and reinstall it.
4. Place a new sealing gasket (with the "TOP" marking facing up) on the cylinder block. Lubricate the edges of the timing belt cover that are mating with the block with sealant. Carefully install the head on the cylinder block.
5. Lubricate the threads and the underside of the heads of the mounting bolts with clean engine oil and screw the fasteners back into place. Tighten the cylinder head mounting bolts in three stages to the required torque, following the exact order (see Fig. Specifications). Due to the critical nature of the bolts, the authors of this Guide recommend that the following precautions be taken when tightening them:
- a) It is preferable to use a torque wrench equipped with a ratchet drive with a torque limiter. Otherwise, proceed with extreme caution, trying not to accidentally strip the threads.
- b) If the bolt starts to make any sounds (squealing, creaking, clicking, etc.) when being screwed in, unscrew it completely and try again.
6. Place the toothed wheel on the camshaft journal (see Section Removal, condition check and installation of the camshaft).
7. Installation of the remaining components is carried out in the reverse order of their dismantling.
8. Don't forget to fill the cooling system and check the levels of all working fluids.
9. Manually turn the crankshaft slowly counterclockwise two full turns.
Caution! If resistance occurs when turning the shaft, stop immediately to avoid damaging the valves when they come into contact with the piston bottoms, return to the original position and check that the timing marks are correctly aligned.
10. Start the engine and check that the ignition timing is set correctly (see Chapter Settings and ongoing maintenance).
11. Warm up the engine to normal operating temperature and check for signs of leaks. Make sure the engine is functioning properly.
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