GM 1644615 Cylinder Head, Machine

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There are two main types of cylinder heads: the Overhead Valve (OHV) and the Overhead Camshaft (OHC). OHC can be further divided into Single Overhead Camshaft (SOHC) and Dual Overhead Camshaft (DOHC). Cylinder heads contain valves, guides, seats, and valve springs. Proper maintenance and tuning of the engine are crucial to prevent wear on these components. When rebuilding a cylinder head, it's ideal to replace all valves, guides, seats, and springs, but depending on the engine's condition, some parts may be reused. The disassembly process involves using a valve spring compressor tool to remove the valves, locks, and springs. Inspection is done for wear and damage, and various specialized tools are used to measure valve clearances, valve guide diameter, and spring pressure. Refinishing and repairing the cylinder head components may require machine shop assistance. Valves may need to be refaced, guides replaced, and seats machined. After thorough cleaning and inspection, the assembly process involves lubricating and inserting valves into their original positions, installing springs, retainers, valve locks, and camshafts for the respective engine type.

To remove and install the cylinder head on a 4.5L or 4.9L engine, start by disconnecting the negative battery cable and draining the engine coolant. Remove the rocker arm covers, lower intake and right side exhaust manifolds, engine lift bracket, and oil dipstick tube. Reposition the AIR bracket and remove the cylinder head bolts to take off the cylinder head. Clean the sealing surfaces and bolt holes before installing a new head gasket over the dowels on the cylinder block. Install the cylinder head and tighten the bolts in the specified sequence and torque. Reinstall the engine lift bracket and AIR bracket, followed by the lower intake and right side exhaust manifolds, and rocker arm covers. Fill the cooling system, reconnect the negative battery cable, and check for leaks after starting the engine. For the left side, follow similar steps but remove the intake manifold, exhaust manifold, and AIR bracket before removing the cylinder head. Clean the gasket mounting surfaces and install the new head gasket before reinstalling the cylinder head and tightening the bolts. Finally, reinstall the AIR bracket, dipstick tube, exhaust manifold, lower intake manifold, rocker arm covers, and fill the cooling system. For the 4.6L engine, it is recommended to remove the entire powertrain and utilize the cradle as an engine-stand for easier cylinder head removal. Remove various components such as the intake manifold, camshaft covers, harmonic balancer, front cover, and oil pump before removing the cylinder head. Clean the gasket surfaces and combustion chamber before installing the new cylinder head with the specified torque for the bolts. Install the camshafts, set the camshaft timing, and install the remaining components before reinstalling the powertrain assembly.