Engine Disassembly + Inspection

Raise the engine and position it next to an engine stand. Mount the engine to the engine stand with bolts. Most stands use a plate with several holes or adjustable arms. The engine must be supported by at least four bolts that fit solidly into it. The engine should be positioned so that its center is in the middle of the engine stand's adapter plate. This will ensure that the engine is not too heavy when rotated on the engine stand.

In most cases, the flywheel or flexplate must be removed to mount the engine on its stand. Mark the position of the flywheel on the crankshaft. This aids the reassembly of the engine. To do this, loosen-but don’t remove-the attaching bolts in a "star" pattern to reduce the chance of distorting the flywheel. At times, the flywheel will turn with the wrench as the bolts are being loosened. When this happens, a fly wheel lock should be used to stop the flywheel from turning. Once all of the bolts are loosened, take hold of the flywheel while removing the bolts. The flywheel can be quite heavy and if it falls, you can be injured or the flywheel can be damaged. The flywheel for manual transmissions should be inspected for possible damage and for signs of clutch problems. Place the flywheel on a flat surface.

Once the engine is securely mounted to the engine stand, remove the sling or lifting chain. The engine can now be disassembled and cleaned. Always refer to the service manual before you start to disassemble an engine.

Slowly disassemble the engine and visually inspect each part for any signs of damage. Look for excessive wear on the moving parts. Check all parts for signs of overheating, unusual wear, and chips. Look for signs of gasket and seal leakage.

USING SERVICE INFORMATION

Look up the specific model car and engine prior to disassembling the engine.

Cylinder Head Removal

The first step in disassembly of an engine is usually the removal of the intake and exhaust manifolds. On some inline engines, the intake and exhaust manifolds are often removed as an assembly.

+++0-21 Remove the valve cover and disassemble the rocker arm components. Check the rocker area for sludge. Keep the rocker arms or rocker arm assemblies in the order they were installed.

+++0-22 When loosening cylinder head bolts; follow the sequence given by the manufacturer.

+++0-23 A major buildup of sludge on the bottom of this oil pan.

+++0-24 From (A) grime to (B) shine.

SHOP TIPS-- It’s important to let an aluminum cylinder head cool before removing it.

To start cylinder head removal, remove the valve cover or covers and disassemble the rocker arm components ( +++0-21) according to the guidelines given by the manufacturer. Check the rocker area for sludge. Excessive buildup can indicate a poor maintenance schedule and is a signal to look for wear on other components.

On OHC engines, the timing belt cover must be removed. Under the cover is the timing belt or chain and sprockets. In the service information, there will be a description of the type and location of the timing marks on the crankshaft and camshaft sprockets. If possible, rotate the crankshaft to check the alignment of the sprockets. If the shafts are not aligned, make note of this for later reference. The valves will hit the pistons on some engines when the timing belt or chain slips, skips, or breaks. These engines are commonly called interference engines. When the valves hit the piston, they will bend. The valves in freewheeling engines won’t hit the piston when valve timing is off. However, the keys and keyways in the camshaft sprocket may be damaged.

Interference engines typically have a decal on the cam cover that states the belt must be changed at a particular mileage interval. Potential valve and/or piston damage is the reason why timing belt replacement is recommended.

The belt or chain must be removed before removing the cylinder head. Locate and move the belt's tensioner pulley to remove its tension on the belt. Slip the belt off the camshaft and crankshaft sprockets, if possible.

When removing the cylinder head, keep the push rods and rocker arms or rocker arm assemblies in exact order. Use an organizing tray or label the parts with a felt-tipped marker to keep them together and labeled accurately. This type of organization greatly aids in diagnosing valve-related problems. Remove the lifters from the block and place them in the order they were installed.

The cylinder head bolts are loosened one or two turns each, following the pattern specified by the manufacturer ( +++0-22). The sequence is typically the opposite of the tightening sequence. If there is no specified procedure, the bolts ought to be loosened one or two turns, beginning in the ends and working toward the center. This prevents the distortion that can occur if bolts are all loosened at once.

The bolts are then removed and the cylinder head can be lifted off. The cylinder head gasket should be saved to compare with the new head gasket during re assembly. Set the cylinder head(s) on cardboard or another soft surface to prevent damage to the sealing surfaces.

Section 12 for the procedures for disassembling and servicing cylinder heads.

The water pump is normally mounted to the front of the engine. Unbolt and remove it. Rotate the engine block so the oil pan is up. Remove the pan's attaching bolts. Then lift off the oil pan. Once the pan is removed, look inside for metal shavings and sludge. Both of these are indications of problems.

Disassembly of the engine block can begin now.

Section 11 for the procedures for disassembling and servicing engine short blocks.

Next: Cleaning Engine Parts

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