Engine Parts: The Names You Need to Know

The core engine parts most people refer to are the engine block, cylinder head, pistons, piston rings, connecting rods, crankshaft, camshaft(s), valves, timing belt/chain, intake and exhaust manifolds, fuel injectors (or carburetor in older engines), throttle body, spark plugs and ignition coils (gasoline) or glow plugs and high‑pressure injectors (diesel), oil pump and oil pan, water pump, radiator and thermostat, gaskets and seals, flywheel/flexplate, and key sensors like oxygen, MAF/MAP, and cam/crank position sensors. Below is a clear, categorized breakdown of engine part names used in modern internal combustion engines, noting where designs differ.

Core Structure and Rotating Assembly

These parts form the engine’s foundation and convert linear piston motion into rotational power. They are common to most four-stroke gasoline and diesel engines.

• Engine block
• Cylinders
• Cylinder head
• Head gasket
• Pistons
• Piston rings
• Wrist pin (gudgeon pin)
• Connecting rods
• Crankshaft
• Crankcase
• Flywheel (manual) / Flexplate (automatic)
• Harmonic balancer (crankshaft damper)
• Timing chain/belt/gearset
• Timing cover
• Valve cover(s) (rocker cover)
• Oil pan (sump)

Together, these components define displacement, compression, and the basic mechanical operation that drives the vehicle’s transmission.

Valvetrain

The valvetrain controls intake and exhaust flow into and out of the cylinders, synchronized with the crankshaft via the timing drive.

• Camshaft(s) (SOHC/DOHC or in-block for OHV)
• Cam phasers (variable valve timing, VVT)
• Lifters (tappets) / Hydraulic lash adjusters
• Pushrods (in OHV/pushrod engines)
• Rocker arms
• Intake valves
• Exhaust valves
• Valve springs
• Valve retainers and keepers (collets)
• Valve guides and valve stem seals

Valvetrain architecture varies widely: overhead cam designs enable higher RPM efficiency, while pushrod (OHV) layouts emphasize compact packaging and low-end torque.

Air and Fuel System

These parts meter, deliver, and mix air and fuel before combustion. Modern engines are largely electronically controlled and fuel-injected.

• Air filter and airbox
• Intake ducting and resonators
• Mass airflow sensor (MAF)
• Manifold absolute pressure sensor (MAP)
• Intake air temperature sensor (IAT)
• Throttle body (or electronic throttle)
• Intake manifold
• Fuel tank
• Fuel pump (in-tank), lift pump (diesel)
• Fuel lines and fuel filter
• Fuel rail
• Fuel injectors (port or direct injection)
• Carburetor (older/legacy engines)
• Positive crankcase ventilation valve (PCV)
• Exhaust gas recirculation valve (EGR) and EGR cooler (where fitted)

Airflow sensing (MAF/MAP) works with throttle position and fuel injection to maintain the correct air–fuel ratio for performance, economy, and emissions.

Ignition (Gasoline) and Combustion Aids (Diesel)

Gasoline Ignition Components

Gasoline engines ignite an air–fuel mixture using a timed spark. These parts generate and time the spark event.

• Spark plugs
• Ignition coils or coil packs (coil-on-plug in most modern engines)
• Ignition wires (older/non-COP systems)
• Distributor and rotor (older systems)
• Crankshaft position sensor (CKP)
• Camshaft position sensor (CMP)
• Knock sensor
• Engine control unit/module (ECU/ECM)

Electronic ignition and coil-on-plug designs have largely replaced distributors, improving reliability and spark precision.

Diesel Fuel/Combustion Components

Diesel engines rely on high compression and precise fuel injection; combustion aids focus on cold starts and high-pressure delivery.

• Glow plugs
• High-pressure fuel pump
• Common-rail (accumulator)
• High-pressure injectors
• Lift pump (low-pressure supply)
• Fuel filter/water separator

Modern common-rail systems enable multiple injection events per cycle, reducing noise and emissions while improving power and efficiency.

Lubrication System

These parts supply, filter, cool, and monitor engine oil to reduce friction and wear and to carry away heat.

• Oil pump
• Pickup tube and strainer
• Oil pan (sump)
• Oil filter
• Oil cooler (engine- or radiator-integrated)
• Oil galleries (internal passages)
• Oil pressure sensor/switch
• Dipstick and filler cap

Healthy oil pressure and filtration are critical for bearing life; many engines integrate coolers to stabilize oil temperature under load.

Cooling System

The cooling system regulates engine temperature for durability and emissions control, especially under varying loads and climates.

• Water pump (coolant pump)
• Radiator
• Thermostat
• Coolant reservoir/expansion tank
• Radiator fan(s) and fan clutch or electric fan module
• Heater core
• Coolant hoses and pipes
• Engine coolant temperature sensor (ECT)

By circulating coolant through the engine, heater core, and radiator, the system prevents overheating and supports cabin heating.

Forced Induction (If Equipped)

Turbochargers and superchargers compress intake air to increase power density; related parts manage boost and temperature.

• Turbocharger (turbine and compressor)
• Wastegate (internal or external)
• Blow-off valve or diverter/recirculation valve
• Intercooler (air-to-air or air-to-liquid)
• Charge pipes/boost hoses
• Boost pressure sensor
• Supercharger (roots, twin-screw, or centrifugal)

Turbo systems are common on modern downsized engines, improving efficiency and torque; intercooling reduces intake air temperature for denser charge.

Exhaust and Emissions

After combustion, exhaust is routed and treated to reduce noise and harmful pollutants before leaving the tailpipe.

• Exhaust manifold
• Oxygen sensors (O2, wideband/AFR)
• Catalytic converter (three-way catalyst)
• Diesel oxidation catalyst (DOC) (diesel)
• Diesel particulate filter (DPF) (diesel)
• Selective catalytic reduction (SCR) system and DEF injector (diesel)
• NOx sensors (diesel)
• Muffler and resonator

Modern emissions systems rely on precise sensor feedback and catalysts to meet stringent regulations while maintaining performance.

Belts, Pulleys, and Accessories

While not all are “inside” the engine, these belt-driven components are integral to engine operation and vehicle systems.

• Serpentine/accessory belt(s)
• Automatic tensioner and idler pulleys
• Alternator
• Power steering pump (or electric power steering module in newer cars)
• Air conditioning compressor
• Vacuum pump (often on turbocharged/diesel engines)

Accessory drives vary by model; many newer vehicles electrify some functions, but belts and pulleys remain widespread.

Engine Control and Key Sensors

Electronic controls coordinate fueling, spark, boost, and emissions through a network of sensors and actuators.

• Engine control unit/module (ECU/ECM)
• Wiring harness and connectors
• Throttle position sensor (TPS) / Accelerator pedal position sensor (APP)
• Crankshaft position sensor (CKP)
• Camshaft position sensor (CMP)
• Mass airflow sensor (MAF)
• Manifold absolute pressure sensor (MAP)
• Intake air temperature sensor (IAT)
• Engine coolant temperature sensor (ECT)
• Oxygen/air–fuel ratio sensors
• Knock sensor
• On-board diagnostics port (OBD-II)

These electronics enable precise, adaptive control, improving drivability, fuel economy, and compliance with emissions standards.

Summary

From the engine block, pistons, crankshaft, and camshafts to the intake, fueling, ignition, lubrication, cooling, exhaust, and control electronics, an engine is a coordinated system of mechanical and electronic parts. The names above cover the standard components you’ll encounter on modern gasoline and diesel engines, with variations based on layout, induction, and emissions technology.