General terms for engine overhaul [Toyota Highlander XU20]

Contents: B ↓ IN ↓ G ↓ D ↓ 3 ↓ TO ↓ L ↓ M ↓ N ↓ ABOUT ↓ P ↓ R ↓ WITH ↓ T ↓ U ↓ F ↓ X ↓ C ↓ Ch ↓ Sh ↓ SCH ↓ Yu ↓

B

Runout is an indicator of uneven shaft rotation.

Backlash - The clearance between two elements. Usually related to gearing, it reflects how much one gear can move relative to the other with which it is engaged, if the other remains stationary.

IN

Sleeve Type Bearing - A solid sleeve that fits into a bore and serves as a bearing for a shaft, piston pin, etc. Bearings are usually replaceable.

Hali-Coil Insert - A sleeve used to restore a threaded hole in case of thread wear or damage. The sleeve is screwed into a hole in which a new thread of a larger diameter has been cut to restore the original thread diameter.

G

Cylinder Liner - A replaceable sleeve that is pressed into the cylinder block to form the actual engine cylinder.

D

Damper - A cylindrical weight mounted on the front end of the crankshaft and used to reduce torsional vibrations (twisting - unwinding of the crankshaft caused by ignition pulses in the cylinders).

Detonation - A loud metallic sound produced in the combustion chamber by abnormal combustion. Should be distinguished from bearing knock, usually caused by loose or worn bearings.

Installed Length - The length of the spring measured after the spring has been installed on the cylinder head. This length is measured from the spring seat to the back of the spring retainer.

Tolerance - A value that characterizes the permitted deviation from an exact size. The tolerance field is the range from the smallest acceptable value to the largest acceptable value.

3

Clearance - Free (idle) play in a gear train or any other mechanical assembly that is "taken up" before movement begins. Usually refers to clearance in a valve train.

TO

Combustion chamber - The space between the piston and the cylinder head when the piston is at top dead center, in which combustion of the air-fuel mixture occurs.

Piston ring groove - An annular groove in the piston crown area used to install the piston ring.

Major repairs – A set of works to restore the condition of the unit, consisting of complete disassembly, inspection of all elements, subsequent assembly using the original or new elements and performing all adjustments necessary for reliable operation.

Engine Crankcase - The lower section of the engine in which the crankshaft operates. Includes the lower section of the cylinder block and the oil pan.

Valve mechanism - The engine mechanism that serves to drive the valves. Includes all elements, from the camshaft to the valves.

Crankshaft - The main rotating element that runs along the engine crankcase and is equipped with offset crankpins to which the connecting rods are connected, and main journals that serve as its supports. Transforms the reciprocating motion of the pistons into rotary motion.

Bearing Race - The inner or outer ring of a bearing that provides the contact surface/raceway for the bearing balls or rollers.

Plastigage Plain Bearing Clearance Measurement Kit - A kit whose main element is a thin plastic thread. There are threads of different sizes. The application scheme is approximately as follows. The thread is placed along the bearing journal and is crushed during the assembly of the mating elements. Then the mating pair of elements is disassembled and the width of the thread is measured to determine the radial clearance between the journal and the bearing. Typically used to measure clearances in the main and connecting rod bearings of the crankshaft.

Crankshaft Kit - Reground or reconditioned crankshaft and new main and rod bearings.

Contact Paint - A blue pigment, in solution, used to define the contact area between two surfaces. Contact paint is typically used to define the width and location of the contact patch between the bevel and the valve seat. It is usually a blue dye.

Taper - A gradual reduction in the diameter of a shaft or bore. In an engine cylinder, taper usually indicates uneven wear, with more at the top than at the bottom.

Main Bearings - Bearings that support the crankshaft. Main bearing shells may be grooved or babbitted.

Connecting rod bearing cap - The part of the connecting rod assembly that serves to secure the connecting rod to the crankshaft journal.

Main Bearing Caps - Cast iron caps bolted to the bottom of the cylinder block. Serve to support the main bearing shells.

Bearing Caps - Caps held in place by nuts or bolts which in turn hold the bearing shells or form the bearing running surface themselves. Lubricant is introduced through the caps.

L

Varnish - A very smooth, glassy "film" that forms on the cylinder walls during engine operation.

M

Seal - A seal that prevents oil from escaping beyond a specified area. Typically used as a seal for a rotating shaft or other moving part.

Oil scraper ring - The lowest piston ring, consisting of several elements and designed to prevent excessive amounts of oil from getting onto the cylinder walls and into the combustion chamber.

Oil gallery - A large passage in the cylinder block through which pressurized engine oil flows.

Tap - A tool used to cut threads in a hole.

Mechanical processing is an operation performed on a machine to remove metal from the surface of a metal element.

N

Carbon - Hard or soft black deposits present in the combustion chamber, on spark plugs, under piston rings, on and under valve heads.

Pilot Bearing - A small bearing mounted in the center of the flywheel (or at the rear end of the crankshaft) and serves as a support for the front end of the primary shaft of the gearbox.

Incomplete cylinder block - A cylinder block assembled with the crankshaft and piston group and, usually, with the camshaft,

ABOUT

Axial clearance – A value that characterizes the possibility of mutual movement of two elements in the longitudinal direction. In relation to the crankshaft, this is the distance that the crankshaft can move in the cylinder block in both directions.

P

Valve resurfacing - Restoring the valve shape using special equipment.

Reduced Oversize Bearings - Bearing shells with reduced diameter used when using a crankshaft with reground journals.

Piston - A cylindrical element connected to a connecting rod that moves back and forth in the cylinder as the crankshaft rotates. When the fuel charge burns, the piston transmits the force of the expanding gases to the connecting rod, which in turn transmits it to the crankshaft.

Piston ring - A split ring that fits into a groove in the piston. The ring contacts the walls of the ring groove, as well as the "mirror" of the cylinder, thereby sealing the gap between the piston and the cylinder. There are two types of rings: compression rings maintain compression pressure in the combustion chamber; oil scraper rings remove excess oil from the cylinder walls.

Piston Pin - Cylindrical (volumetrically hollow) a steel rod that runs across the piston and serves to secure the piston to the upper end of the connecting rod.

Press Fit - A tight fit between two members that requires significant force to assemble the members. Also referred to as an interference fit.

Bearing Shell Diameter Allowance - Allowance provided on each bearing shell to ensure full contact between the back of the shell and the housing bore during engine assembly.

Running-in - The period of operation between the moment of installation of new or restored components and the moment when the components wear to the point of ensuring correct seating. In order to ensure running-in to ensure correct seating, it is recommended to drive at reduced speed, varying it, during the prescribed mileage.

Valve lapping - Grinding the valve chamfer and its seat using a lapping fin.

R

Radial Bearing Clearance – The clearance between the shaft and the bearing running surface, measured in the radial direction. This is the place for introducing grease.

Crank radius – The amount of displacement of the crankpin of the crankshaft.

Reaming - To bring a hole to the required size, enlarge it, or improve its surface quality using a suitable tool called a reamer.

Camshaft – The engine shaft that has a series of cams to drive the valve mechanisms. The camshaft is driven by a belt/chain or gear drive.

Boring – A mechanical processing operation of an engine cylinder in order to bring its diameter to the prescribed size.

Cooling jacket - A chamber around the cylinders between the inner and outer walls of the block or cylinder head through which coolant circulates.

WITH

Free Length/Height - The length/height of an element in the unloaded state, such as the free length of a spring.

Free Play - The gap in a linkage or assembly between the start of force application and the actual start of movement. Usually perceived as a slight delay.

Segment key - A key with a rounded bottom side (side view).

Seat - The surface on which another element rests or "sits" For example, a valve seat is the element that the valve face mates with

Deburring - Removing irregularities (sharp edges and burrs) from the liners and working surfaces of bearings.

Wear - A type of wear in which there is a transfer of material between elements moving relative to each other. Appears as "ripples" or grooves on the mating surfaces.

Static balance - The equilibrium of an object when it is stationary.

Compression ratio - The ratio between the volume of a cylinder when the piston is at top dead center (combustion chamber volume), and the volume of the cylinder when the piston is at bottom dead center.

Core Plug - A soft metal plug used to seal the coolant passage casting holes in the cylinder block.

Bearing knock - Noise created when an element moves in a loose or worn bearing. Bearing knock in connecting rod or main bearings is caused by too much radial clearance or insufficient lubrication.

Crackers - The components that hold the valve spring retainer on the valve stem.

T

Tappet - An element that is in contact with the camshaft lobe and serves to transmit movement to the rest of the valve train.

U

O-ring - A sealing ring made of a special rubber-like material. To ensure a tight seal, the O-ring is inserted into a specially shaped groove provided.

Thrust Washer - A bronze or hardened steel washer installed between two moving parts. The washer prevents longitudinal movement of the elements and provides a mating surface with the surfaces of the elements experiencing axial pressure.

Thrust Bearing - A main bearing that has thrust surfaces to prevent excessive end play or forward and backward movement of the crankshaft.

Fatigue - The failure of a material over a large number of loading and unloading cycles. The first sign of fatigue is cracking, soon followed by rupture.

Installation marking - Small (for example, a center-punched one) a point that shows the top surface of the compression ring.

F

Chamfer - A bevel across the sharp edge of an object.

X

Piston Stroke - The distance the piston travels when moving from top dead center to bottom dead center or vice versa.

C

Scratches - Damage to the cylinder "mirror" surface that can result from piston rings moving hard particles along the cylinder walls.

Ch

Cast iron - An alloy of iron and carbon (more than 2%) used to make cylinder blocks and heads because it is relatively inexpensive and has good casting qualities for casting into complex shapes.

Sh

Connecting rod - A lever that connects the crankshaft journal to the piston.

Connecting rod journal - The part of the crankshaft to which the connecting rod is attached.

Neck - The part of a rotating shaft that rotates in a bearing.

Stud - A metal rod with threads at both ends.

Spline - A small metal piece that fits into matching slots in two mating components (for example, when pressing a gear onto a shaft) and preventing mutual angular displacement of these two elements.