Mercury 8R3Z-6049-A Cylinder Head Assembly

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1. Relieve the fuel system pressure and disconnect the cable from the negative battery terminal. 2. Drain the cooling system. 3. Remove the intake manifold and the exhaust manifolds. 4. Remove the valve covers. 5. Remove the drivebelt and the drivebelt tensioner. 6. Remove the camshafts and lifters. 7. Remove the two Camshaft Position (CMP) sensors at the rear of each cylinder head and disconnect any other electrical connectors.

New cylinder head bolts must be used for reassembly. Failure to use new bolts may result in cylinder head gasket leakage and engine damage. 15. The mating surfaces of the cylinder heads and engine block must be perfectly clean when the cylinder heads are installed. Use a gasket scraper to remove all traces of carbon and old gasket material, then clean the mating surfaces with lacquer thinner or acetone. If there's oil on the mating surfaces when the cylinder heads are installed, the gaskets may not seal correctly and leaks may develop. Cover the open areas of the engine with shop rags to keep debris out during repair and reassembly. Use a vacuum cleaner to remove any debris that falls into the cylinders. Do not use abrasive wheels or sharp metal scrapers on the heads or block surface; use a plastic scraper and chemical gasket remover, or the head gasket surfaces could develop leaks. 16. Check the engine block and cylinder head mating surfaces for nicks, deep scratches, and other damage. 17. Use a tap of the correct size to chase the threads in the cylinder head bolt holes. Dirt, corrosion, sealant, and damaged threads will affect torque readings. 18. Make sure the new gaskets are installed on the correct cylinder banks (Identify the left and right cylinder head gaskets; the shapes are different and cannot be interchanged). 19. Position the new gasket(s) over the alignment dowels in the engine block. 20. Carefully position the cylinder heads on the engine block without disturbing the gaskets. Install the NEW cylinder head bolts (the cylinder head bolts are torque-to-yield design and they cannot be reused). Following the recommended sequence, tighten the cylinder head bolts in five steps, to the torque and angle of rotation. Note: The method used for the cylinder head bolt tightening procedure is referred to as "torque-angle" or "torque-to-yield" method. Follow the procedure exactly. Tighten the bolts in the first step using a torque wrench, then use a breaker bar and a special torque-angle gauge to tighten the bolts the required angle. If the adapter is not available, mark each bolt with a paint stripe to aid in the torque angle process. 21. The remaining installation steps are the reverse of removal. 22. Install the engine. 23. Change the engine oil and filter and refill the cooling system, then start the engine and check carefully for oil and coolant leaks.

The head should be thoroughly cleaned and inspected, and if a complete engine overhaul is being done, finish the engine disassembly procedures before starting the cylinder head cleaning and inspection process.

If the inspection indicates that the valve components are in generally poor condition and worn beyond specified limits, reassemble the valves in the cylinder head.

Loosen the cylinder head bolts in 1/4-turn increments until they can be removed by hand, working in a reverse pattern of the tightening sequence.

The remaining installation steps are the reverse of removal, and then change the engine oil and filter before starting the engine and checking for leaks.

Check the installed valve spring height with a ruler graduated in 1/32-inch increments or a dial caliper. If the head was sent out for service work, the installed height should be correct, but don't automatically assume that it is. The measurement is taken from the top of each spring seat or shim(s) to the bottom of the retainer.

Apply a small dab of grease to each keeper to hold it in place. Compress the springs with a valve spring compressor and carefully install the keepers in the upper groove, then slowly release the compressor and ensure the keepers seat properly.

Position the new gasket(s) over the dowel pins in the engine block, ensuring they are oriented correctly.

Clean all the valve springs, spring seats, keepers, and retainers with solvent and dry them thoroughly, working on one valve at a time to avoid mixing up the parts.

Use the required camshaft retaining fixtures to lock the camshafts and leave the tools in place.

The head should be thoroughly cleaned and inspected, and if a complete engine overhaul is being done, finish the engine disassembly procedures before starting the cylinder head cleaning and inspection process.

The remaining installation steps are the reverse of removal.

Remove the exhaust manifold.

The remainder of the installation is the reverse of removal. Change the engine oil and filter, refill the cooling system, then start the engine and check carefully for oil and coolant leaks.