********** Engine **********
Turns Over (cranks) - engine spins with starter motor but doesn't fire
Catches - sporadic combustion events and kicking but not running
Backfire - combustion that blasts out the tailpipe, loud sometimes smoke
Pop - combustion that comes up the carb, muted by air filter if on, scary pow if air filter is off ... good idea to keep cranking to suck any flame back into the engine
Ping - can be a subtle rattle sound, but it is very damaging detonation under full load due to overheat or advanced timing
Rattle - can be a dumb loose bracket or tin, or internal part failure, like loosening valve clearances
Knock - dumb loose large part hitting, or dangerous internal large part loosening up, like connecting rod bearing failure or worn main bearings
Tick - most usually a benign loose valve/hydraulic lifter
Thump - out-of-round tires dragging out-of-round brake drums/rotors, loose or damaged shock bushings
Whine - electrical interference through radio, bad alternator/generator bearing, bad transmission bearing, fresh generator commutator (benign)
Whistle - benign air flow sound through FI throttle body, vacuum leak, fresh air leak through seals or ventilation
Whir - cam gear mesh, distributor bushings, generator/alternator brushes, foreign object rubbing v-belt
Surge - a noticeable change in power output while accelerating
Miss - either intermittent or steady negative pulse most usually indicating a loss of spark or dead cylinder
Hesitate - a full engine intermittent loss of power
Lean - insufficient fuel at the combustion chambers > low power and hesitation, gets worse as engine warms up
Rich - too much fuel at combustion chambers causes stumbling and low power but can run really well when cold
Overrun - any time the car is pushing the engine, as in engine braking
Accelerate - when engine or car is increasing in rpm or speed
Decelerate - when engine or car is losing rpm or speed
Light throttle - just off idle operation or slow rate of acceleration
WOT (Wide-Open Throttle) - pedal-to-the-metal full acceleration where engine vacuum is at its lowest
Clearance - the space required for parts to function through expansion and contraction based changes of dimension, usually measured in thousandths of an inch
Play(end-play) - the space required for parts to function through expansion or contraction or load
Slop - unintended clearances or play due to wear
Preload - the intentional running of parts under contact load, like steering gear or differential ring and pinion
Seize - the unintended bonding of two parts that wish they didn't > most usually under heat and friction
Grenade - colloquial term describing the destruction of a complex assembly like an engine or transaxle where destroyed parts destroy other parts > necessitates a rebuild or replacement of engine
Valve Drop - a catastrophic release of a valve from its retainer where it falls into the piston > necessitates a rebuild
Seat recession - the movement or erosion of the hard steel ring that seals valves in the cylinder heads > necessitates a rebuild
Smokes - the burning of oil either through the engine or on hot surfaces
Drips - usually oil sometimes gas or brake fluid or gear oil > always investigate
Flooding - the uncontrolled dumping of gasoline into the carburetor or the rich stall of an engine due to too much fuel delivery
Starvation - inadequate fuel (or oil supply > a dangerous condition)
TDC (Top Dead Center) - piston at the very top of the cylinder, an important reference point for timing the spark or setting parts to be synchronized with each other
BTDC (Before Top Dead Center) - the movement of the crankshaft in degrees before the piston arrives at the top of the cylinder
ATDC (After Top Dead Center) - the movement of the crankshaft in degrees after the piston goes down the cylinder
Combustion Chamber- the specially shaped portion of the cylinder heads where the valves and spark plug reside and combustion is enhanced
Thrust Bearing - any surface that has to resist axial movement of a rotating part
Bearing Saddle - the structure under main bearings that supports and absorbs combustion and rotational forces
Bearing Inserts - replaceable surfaces that ride against rotating parts
Bearing over/undersize - optional size replacement bearings that are matched to reconditioned machined under or over-sized rotating parts
Engine Glossary
- Amskeptic
- IAC "Help Desk"
- Status: Offline
Engine Glossary
BobD - 78 Bus . . . 112,730 miles
Chloe - 70 bus . . . 217,593 miles
Naranja - 77 Westy . . . 142,970 miles
Pluck - 1973 Squareback . . . . . . 55,600 miles
Alexus - 91 Lexus LS400 . . . 96,675 miles
Chloe - 70 bus . . . 217,593 miles
Naranja - 77 Westy . . . 142,970 miles
Pluck - 1973 Squareback . . . . . . 55,600 miles
Alexus - 91 Lexus LS400 . . . 96,675 miles