Cylinder Heads

Cylinder Block

The cylinder block is the main engine casting housing the cylinders, crankshaft, and oil galleries. When sourcing a used block:

• Verify the casting number matches your engine family and displacement

• Inspect cylinder bores for scoring, cracks, or out-of-round wear (requires measurement with a bore gauge)

• Check main bearing journal condition — scoring indicates inadequate lubrication history

• Confirm the deck surface is flat (a warped deck requires machining before use)

A used block typically requires machine shop evaluation before committing to a rebuild.

Crankshaft

The crankshaft converts piston motion to rotation. When sourcing a used crankshaft, have the main and rod journals measured for size and taper — worn journals require grinding to the next undersize, which requires matching undersize bearings. Check for cracks with magnetic particle inspection if the source vehicle had a known engine failure.

Cylinder Head

Cylinder heads are among the most commonly sourced used engine components — often for head gasket repairs where only the head needs replacement. Critical checks:

• Have the deck surface measured for flatness — a warped head surface must be machined

• Inspect valve seats and guides for recession or cracking

• Check for cracks between valve seats and around combustion chamber edges (common on aluminum heads after overheating)

• Verify the casting number matches your application — the same engine may have multiple head castings with different port configurations

Always install new head gaskets and ARP head studs or bolts — never reuse head gasket hardware.

Camshaft

The camshaft profile determines valve lift and timing, directly affecting engine power character. When buying used, verify the cam lobes show no flat spots (which indicate spalling or wear). Camshafts are specific to engine family and grind specification — a performance cam from the same engine block will change the power delivery characteristics.

Camshaft Housing

The camshaft housing is the casting that supports the camshaft and its bearings, used on overhead-cam engines where the cam rides in a dedicated carrier rather than the head itself. Match the housing to your exact engine and cam configuration, and inspect the bearing bores for scoring before reuse.

Timing Cover

The timing cover seals the front of the engine block, houses the front crankshaft seal, and on some engines mounts the water pump. Match by part number — the timing cover is engine-specific and may include or exclude water pump provisions depending on the application.

Oil Pan

The oil pan serves as the engine's oil reservoir and is typically replaced after impact damage or severe corrosion. On many vehicles, removing the oil pan requires partially lowering the engine or subframe — factor this into labor cost estimates. Always use a new gasket; RTV alone is not a reliable seal on most applications.

Engine Oil Cooler

The oil cooler is a heat exchanger (usually coolant-to-oil) that keeps oil temperature in range during heavy use. On diesel and turbocharged engines, this is a common failure point — internal contamination (oil in coolant or coolant in oil) often points to oil cooler failure. When replacing, always flush the cooling system thoroughly after an oil cooler failure.

Harmonic Balancer

The harmonic balancer (crankshaft damper) absorbs torsional vibration and drives the serpentine belt. A common failure mode is rubber layer separation — the outer ring separates slightly from the inner hub, causing vibration and timing mark inaccuracy. Verify the timing marks on the replacement match the original orientation. A special puller and installer tool is required; never hammer a harmonic balancer onto the crankshaft snout.

Vacuum Pump

The vacuum pump generates brake booster vacuum on engines that lack sufficient intake manifold vacuum, such as diesels and many turbocharged or direct-injection gasoline engines. It is a straightforward used-part replacement — verify the mounting bolt pattern, outlet port sizes, and drive type (gear or belt driven) match the engine's provisions.

Secondary Air Injection Pump

The secondary air injection pump injects air into the exhaust during cold start to reduce emissions. It is a relatively straightforward used-part replacement — verify the mounting bolt pattern and outlet port sizes match. A failed secondary air pump commonly triggers an emissions-related check engine code.