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Aftermarket
Replacement parts not made by the original manufacturer but designed to function the same or improve upon OEM specifications. Often used for performance enhancements.

Alternator
A generator that produces alternating current (AC) to charge the battery and power the electrical system when the engine is running.

Assembly Lube
A high-viscosity lubricant applied during engine assembly to protect components during initial start-up before oil circulation.

Backlash
The amount of play between two meshing gears, such as camshaft and distributor gears. Critical to timing precision.

Balance Shaft
A weighted shaft used to counteract engine vibration in inline or V-type engines.

Bore
The diameter of the engine cylinder. Overboring is common in rebuilds to restore worn cylinders or increase displacement.

Blueprinting
A precise engine build process in which all components are machined and assembled to exact tolerances—often exceeding factory specifications.

Camshaft
A rotating shaft with lobes that open and close the intake and exhaust valves in timed sequence with the piston strokes.

Carburetor
A device that mixes air and fuel for combustion in pre-fuel injection engines. Performance rebuilds often involve tuning or replacing carburetors.

Clearance
The measured space between moving parts, such as between the piston and cylinder wall or crankshaft and bearings.

Compression Ratio
The ratio of the total cylinder volume when the piston is at the bottom of its stroke to the volume when it’s at the top. Higher ratios can improve performance.

Crankshaft
The main rotating component that converts the pistons’ linear motion into rotational energy to drive the vehicle.

Cylinder Hone
A tool used to create a crosshatch pattern in cylinder walls for proper piston ring seating during break-in.

Deck Height
The distance between the cylinder head mounting surface and the piston at top dead center (TDC). Affects compression ratio and squish.

Detonation
Uncontrolled combustion in the cylinder, often caused by improper timing or low-octane fuel. Damaging to engine components.

Distributor
A mechanical device that routes high voltage from the ignition coil to the correct spark plug at the correct time.

Drag Racing Cam
A high-lift, long-duration camshaft designed to keep valves open longer at high RPM for maximum power in short bursts.

Exhaust Manifold
Channels exhaust gases from the cylinder head to the exhaust pipe. Often upgraded to headers for performance builds.

Expansion Plug (Freeze Plug)
A plug fitted into the engine block to allow for expansion due to freezing coolant or to seal casting holes.

Feeler Gauge
A precision measuring tool used to set valve lash, spark plug gap, and other critical engine clearances.

Flathead Engine
An older engine design with valves located in the block rather than the head. Known for simplicity and ease of modification.

Flywheel
A rotating mass attached to the crankshaft that helps smooth engine operation and engages with the clutch in manual transmissions.

Gasket
A sealing material placed between two mating surfaces to prevent leakage of oil, coolant, or combustion gases.

Gapless Rings
Piston rings designed with a secondary rail to minimize combustion leakage, used in high-performance and drag engines.

Harmonic Balancer
A crankshaft-mounted device that reduces engine vibration and prolongs crankshaft life.

High-Lift Cam
A camshaft with lobes designed to open the valves farther than stock, allowing more air/fuel mixture in and more exhaust out—ideal for racing applications.

Honing
The process of finishing cylinder walls with abrasive stones to restore proper surface finish and geometry.

Ignition Points
Part of a contact breaker system that opens and closes to trigger spark. Typically used with a condenser in older ignition systems.

Intake Manifold
Distributes the air/fuel mixture from the carburetor to the intake ports of the cylinder head.

Lifters (Tappets)
Riding on the camshaft, lifters transfer cam lobe motion to pushrods (in OHV engines) or directly to valves (in OHC engines).

Line Boring
A precision machining process to restore or align the main bearing bores in the engine block.

Main Bearings
Support the crankshaft and allow it to rotate within the engine block. Precision fitting is essential in a rebuild.

Magneto
An ignition device generating current independently of the battery, used in early performance and race engines.

Micrometer
Precision measuring tool used to measure diameters, thicknesses, or small distances, essential in engine assembly.

Oil Pump
Circulates engine oil to bearings, camshaft, and valve train. High-performance pumps often used in racing builds.

Overbore
Enlarging the cylinder bore during machining to remove wear or increase engine displacement.

Overhead Valve (OHV)
An engine design where the camshaft is in the block and operates the valves via lifters, pushrods, and rocker arms.

Piston
A cylindrical component that moves up and down within the cylinder, transferring combustion force to the crankshaft.

Piston Rings
Seals fitted around pistons to maintain compression and control oil. Typically include compression rings and oil control rings.

Plastigauge
A thin plastic thread used to measure bearing clearance by flattening under torque to give an accurate reading.

Points and Condenser
Part of traditional ignition systems, where points open to break the coil’s primary circuit, and the condenser prevents arcing.

Porting
Modifying the intake and exhaust ports in the cylinder head to improve airflow and performance.

Pushrod
Connects the lifter to the rocker arm in OHV engines to transfer motion for valve actuation.

Rocker Arm
Pivots on a shaft or stud to open the valves when actuated by pushrods or camshaft lobes.

Rod Bearings
Bearings between the connecting rods and crankshaft journals, allowing smooth movement under load.

Runout Gauge (Dial Indicator)
Used to measure shaft straightness or flatness on surfaces—critical in crank and camshaft inspection.

Seat Cutting
Machining valve seats for proper angle and surface finish to ensure a good seal with the valve.

Shim
Thin spacer used to adjust clearances in valve trains, bearing assemblies, or timing components.

Short Block
An engine subassembly that includes the block, crankshaft, pistons, and rods—excluding the cylinder head and valve train.

Stroker Kit
A modified crankshaft and rod combination that increases stroke length and engine displacement.

Tappet Noise
A ticking sound caused by excessive valve lash or worn lifters, often addressed during rebuilds.

Timing Chain (or Belt)
Synchronizes the crankshaft and camshaft to ensure valves open and close at correct intervals.

Torque Wrench
A tool used to apply precise torque to fasteners, critical in engine assembly to avoid distortion or damage.

Total Seal Rings
Performance piston rings designed to eliminate blow-by and improve sealing in high-output engines.

Valve Float
A condition where the valve spring can’t control valve movement at high RPM, causing loss of performance or engine damage.

Valve Guide
A cylindrical insert that stabilizes valve movement within the head, often replaced during rebuilds.

Valve Seat
The surface in the head against which the valve seals when closed. Precision machining is key for performance engines.

Valve Spring Compressor
A tool used to compress valve springs for removal or installation of valves and retainers.

Wrist Pin (Gudgeon Pin)
A hardened pin connecting the piston to the connecting rod, allowing pivoting movement during combustion cycles.

WOT (Wide Open Throttle)
A term indicating maximum throttle input. Tuning for WOT is critical in drag racing and performance applications.

Air/Fuel Ratio (AFR)
The proportion of air to fuel in the combustion mixture. Performance tuning seeks ideal AFR (around 12.5:1 for max power in petrol engines) for optimal combustion.

Anodizing
An electrochemical treatment for aluminum components that increases corrosion resistance and wear durability—often used on pistons, pulleys, and brackets.

Blow-Off Valve (BOV)
A valve used in turbocharged systems to release excess boost pressure when the throttle is closed, preventing compressor surge.

Boost
The amount of positive pressure (above atmospheric) delivered by a turbocharger or supercharger. Measured in PSI or bar.

Boost Controller
A device or system used to regulate the pressure created by a turbo or supercharger, allowing for performance tuning or boost targeting.

Capacitor Discharge Ignition (CDI)
A high-energy ignition system common in racing applications that rapidly discharges a capacitor to fire the spark plug with high voltage and speed.

Catch Can (Oil Breather Tank)
Captures excess crankcase vapors, oil mist, and fuel blow-by to reduce engine contamination and maintain performance consistency.

Cage Nut
Often used in race chassis or modular paneling where quick disassembly is required—relevant in engine bay access for drag builds.

Data Logger
A digital system that records engine performance parameters (RPM, AFR, ignition timing, temperature) in real-time for post-run analysis.

Decking the Block
Machining the top of the engine block to ensure it's flat and square to the crankshaft centerline, often used to raise compression in performance engines.

Fuel Cell
A specialized fuel tank used in race vehicles with internal baffling and foam to prevent fuel slosh and ensure constant fuel pickup.

Fuel Pressure Regulator
A device that maintains consistent fuel pressure to the injectors or carburetor, critical in high-performance fuel delivery systems.

Fuel Rails
Manifolds that distribute fuel to injectors in EFI systems. High-flow versions used in racing applications to support power upgrades.

Header (Exhaust Header)
An aftermarket performance manifold designed to optimize exhaust gas scavenging and reduce backpressure compared to factory manifolds.

Heat Soak
Performance degradation due to heat saturation of components like intake manifolds, turbos, or ignition coils. Heat management is key in racing engines.

Ignition Advance
The act of firing the spark plug earlier in the cycle to allow more complete combustion—adjusted during performance tuning for power gains.

Intercooler
Used in turbocharged or supercharged engines to cool the compressed air before it enters the combustion chamber, increasing air density and preventing detonation.

Line Lock
An electronically controlled valve that locks the front brakes independently, allowing a car to perform a burnout without moving forward. Common in drag racing.

Launch Control
A system or method for achieving optimal RPM and traction at the start of a race. Often mechanical in classic race cars or electronically managed in modern builds.

Methanol Injection
A system that sprays methanol (or a water-methanol mix) into the intake to reduce charge air temperature, suppress detonation, and increase power—especially in forced-induction setups.

Nitrous Oxide (N₂O)
A chemical used in performance systems to deliver additional oxygen during combustion, creating significant power boosts. Known as “spray” or “laughing gas.”

Nitrous Plate Kit
A system that injects nitrous and fuel between the carburetor and intake manifold. Often used in classic drag racing applications.

Power Adder
Any system that increases engine output beyond naturally aspirated design, such as turbochargers, superchargers, or nitrous oxide systems.

Purge Valve (Nitrous)
A solenoid valve that vents trapped air or vapor from the nitrous line, ensuring a pure nitrous hit when activated.

Rev Limiter
A control mechanism (mechanical or electronic) that prevents the engine from exceeding a specified RPM, protecting components from damage.

Roller Rockers
High-performance rocker arms fitted with rolling tips to reduce friction and improve valve control at high RPMs.

Slicks
Drag racing tires with no tread designed for maximum traction under high power launches. Not road legal.

Scavenge Pump
Used in dry sump oil systems to remove oil from the crankcase and return it to a remote reservoir—common in racing engines for oil control.

Supercharger
A belt-driven forced induction system that compresses intake air, improving engine power. Roots and centrifugal types are popular in classic drag engines.

Timing Light
A tool used to visually inspect and adjust ignition timing by flashing a strobe light synced with the engine’s firing.

Turbocharger
A turbine-driven forced induction system powered by exhaust gases. Increases intake pressure and engine output dramatically.

Tuned Length Header
An exhaust header engineered with primary tubes of equal length to optimize pulse timing for maximum scavenging and performance.

Vacuum Advance
A mechanism in some distributors that adjusts ignition timing based on engine load by using intake manifold vacuum—often removed or locked out in race engines.

Valvetrain Geometry
The alignment and movement dynamics of lifters, pushrods, rocker arms, and valves. Precision setup is critical for high-RPM durability.

Wastegate
A valve that diverts exhaust gases away from the turbocharger turbine to control boost pressure and prevent overboost.

Wet Sump / Dry Sump
Two oiling systems: Wet sump stores oil in the engine pan, while dry sump stores oil in a separate tank and uses scavenge pumps—ideal for high-G race conditions.