Automotive Technology: Engine Disassembly and Lower End Service

Vocabulary practice flashcards covering engine disassembly, cleaning methods, crack detection, in-vehicle engine service, cylinder block reconditioning, and lower end component inspection and assembly.

Memory Saver

A backup power device installed prior to disconnecting the vehicle's battery to preserve computer memory and electronic presets.

Water-Soluble Soils

Engine contaminants that include dirt, dust, and mud, which can be dissolved or rinsed away with water.

Organic Soils

Petroleum- and carbon-based engine contaminants including oil, grease, varnish, gum, sludge, and carbon.

Scale

A mineral crust deposited on internal engine coolant passages that forms when minerals separate out from heated water.

Parts Washer (Solvent Tank)

An inexpensive and widely used shop apparatus that circulates solvent over metal surfaces to wash away grease, oil, and loose dirt.

Hot Tank

An engine cleaning system that uses heated chemical solutions in an immersion tank, often aided by liquid or mechanical parts agitation to loosen grime and reach blind passages.

Thermal Cleaning

A cleaning method relying on heat inside a dedicated oven to bake off oil and grease, leaving behind a powdery ash that is subsequently washed or shot-blasted away.

Abrasive Cleaning

A mechanical cleaning process that propels blasting media against dry, grease-free components to scour away stubborn deposits.

Vibratory Cleaning (Shakers)

A cleaning method using a vibrating tub packed with ceramic steel, porcelain, or aluminum abrasive media while circulating solvent to scrub components.

Ultrasonic Cleaning

A cleaning technique utilizing high-frequency sound waves in a liquid bath to generate microscopic bubbles that collapse violently, loosening soil while minimizing chemical usage.

Salt Bath

A cleaning process that utilizes high-temperature molten salt operating at $370^\circ\text{C to }450^\circ\text{C}$ for cast iron/steel, or about $315^\circ\text{C}$ for aluminum, to dissolve organic materials, grease, paint, and gaskets.

Magnetic Particle Inspection (MPI)

A non-destructive crack-detection method for cast-iron parts that uses an electromagnet or permanent magnet and sprinkled iron filings to expose secondary magnetic poles caused by cracks.

Dye Penetrant Inspection

A three-part chemical inspection process (penetrant, cleaner, and developer) for non-magnetic metals where the penetrant dwells for 5 minutes before removal to reveal cracks as distinct red lines.

Tungsten Inert Gas (TIG / GTAW) Welding

The preferred repair method for damaged or cracked aluminum cylinder heads, where the weld puddle is continuously shielded by inert gas to prevent surface oxide from reforming.

Cylinder Head De-torque Pattern

The manufacturer-specified reverse order for progressively loosening cylinder head bolts to prevent warpage or cracking of the head casting during disassembly.

Torque-to-Yield (TTY) Bolts

Engine fasteners engineered to stretch permanently into their plastic zone upon final angle tightening; they can never be reused and must be replaced after removal.

Short Block

An engine assembly consisting of the cylinder block, crankshaft, crankshaft bearings, connecting rods, pistons and rings, oil gallery plugs, and core plugs.

Harmonic Balancer (Vibration Damper)

A crankshaft assembly composed of an inner cast-iron hub bonded by an elastomer (rubber) sleeve to an outer inertia ring, designed to absorb torsional crankshaft vibrations.

Cylinder Ridge

A band of unworn metal accompanied by carbon buildup located at the very top of the cylinder bore above the travel limit of the top compression ring.

Ridge Reamer

A specialized reaming tool rotated clockwise inside the cylinder to shave away the unworn upper ridge before extracting the piston and connecting rod assembly.

Core Plugs (Expansion Plugs)

Machined metal caps or discs installed into casting holes to seal off the openings created to remove sand cores from the cylinder block.

Cylinder Bore Taper

The dimensional difference between the diameter at the bottom of the cylinder bore and the top of the bore just below the ridge, typically permissible up to $0.1524\,mm$ ($0.006\,in.$).

Cylinder Bore Out-of-Roundness

The difference between cylinder bore diameter measurements taken parallel to the crankshaft versus perpendicular to the crankshaft just below the ridge, with a maximum allowable limit typically of $0.0381\,mm$ ($0.0015\,in.$).

Dial Bore Gauge

A precision measuring gauge with arms aligned parallel to the plane of the crankshaft and rocked back and forth until the smallest reading is found to measure bore diameter, taper, and out-of-roundness.

Crosshatch Pattern

A cylinder wall finish composed of tiny crisscross grooves intersecting at $50^\circ\text{ to }60^\circ$ (acceptable between $20^\circ\text{ to }60^\circ$) that provides oil retention reservoirs and bearing plateaux for piston rings.

Torque Plate

A rigid metal plate bolted to the top deck of an engine block to simulate the weight, strain, and distortion of a torqued cylinder head during cylinder boring or honing.

Ball Hone

A flexible abrasive honing tool consisting of small abrasive balls used to deglaze cylinder walls and establish the specified plateau crosshatch pattern.

Boring Bar

A rigid cutting machine used to machine oversized cylinder bores or prep the block for repair sleeves when cylinders are heavily scored, tapered, or worn.

Line Boring

A specialized machining operation in which main bearing housing bores and camshaft bearing bores are rebored to restore original standard diameter and precise axial alignment.

Camshaft End Play

The allowable forward-to-backward axial movement of a camshaft inside the block or head, measured using a dial indicator mounted to the block while prying the cam sprocket.

Lifter Rotation

The intentional spinning of a mechanical or hydraulic lifter caused by an offset contact pattern between the spherical lifter bottom and the tapered cam lobe, designed to reduce sliding friction and distribute wear evenly.

Total Indicator Reading (TIR)

The total needle sweep (positive plus negative deflection) on a dial indicator when rotating a crankshaft supported on V-blocks; crankshaft bow equals 50 percent of this reading.

Insert Bearings

Precision-manufactured replaceable bearing shells used in engines, produced in either full-round (one-piece) or split (two halves) configurations.

Thrust Bearing

A crankshaft main bearing equipped with integral flanged side faces designed to control and limit crankshaft horizontal end play.

Bearing Spread

A design characteristic where the distance across the parting edges of an uninstalled bearing insert is slightly wider than the housing bore, holding the insert positively in place during assembly.

Bearing Crush

An engineered feature where each bearing insert is slightly greater than a true half-circle, forcing the bearing shells tightly into the housing bore when torqued to improve heat dissipation and prevent rotation.

Locating Lug

A stamped indexing tab projecting from the parting face of a bearing shell that fits into a machined slot in the housing bore to align the bearing and prevent lateral shift.

Undersize Bearings

Thicker-walled engine bearings manufactured for use on crankshaft journals that have been worn or reground to smaller-than-standard diameters.

Plastigage

A calibrated deformable plastic thread placed across a journal that measures oil clearance according to the width to which it flattens when the bearing cap is torqued.

Crankshaft End Play

The fore-and-aft clearance between the crankshaft thrust cheeks and the flanges of the thrust bearing, measured using either a feeler gauge or a dial indicator.

Hypereutectic Piston

An aluminum piston cast with a silicon concentration above 12%, providing low thermal expansion, high temperature resistance, high strength, and superior ring groove wear resistance.

Eutectic Piston

An aluminum piston formulation containing 11% to 12% silicon that provides good structural strength and economical production.

Hypoeutectic Piston

An aluminum piston alloy with approximately 9% silicon content, commonly found in older engine designs.

Piston Pin Boss

The reinforced internal structure inside the piston supporting the wrist pin bore, often machined slightly offset toward the major thrust side to reduce engine noise.

Piston Ring Side Clearance

The vertical clearance gap between the side surface of a piston ring and the top land of the piston ring groove, measured with a feeler gauge.

Connecting Rod Side Clearance

The axial clearance between the side of the connecting rod big end and the machined cheek of the crankshaft journal, measured using a feeler gauge.