B
Runout - An indicator of uneven rotation of the shaft.
Side clearance - The clearance between two elements. Usually refers to a gear train and reflects how much one gear can move relative to the other with which it is engaged, if the second one remains stationary.
IN
Sleeve type bushing - A monolithic bushing that is installed in a bore and serves as a bearing for the shaft, piston pin, etc. Usually the liners can be replaced.
Hali-Coil Insert - A sleeve used to restore a threaded hole in the event of wear or damage to the thread. The sleeve is screwed into a hole in which a new thread of a larger diameter is cut to restore the original thread diameter.
G
Cylinder liner - A replacement 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 - untwisting of the crankshaft caused by ignition pulses in the cylinders).
Detonation - A strong metallic sound produced in the combustion chamber as a result of abnormal combustion. To be distinguished from bearing knocking, 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 cup.
Tolerance - A value that characterizes the permitted deviation from the exact size. The tolerance band is the range from the smallest acceptable value to the largest acceptable value.
3
Clearance - Free (idle) travel in a gear train or any other mechanical assembly that «is chosen» before starting to move. Usually refers to valve clearance.
TO
Combustion chamber - The space between the piston and the cylinder head when the piston is at top dead center, in which the combustion of the air-fuel mixture occurs.
Piston Ring Groove - An annular groove in the area of the piston crown that serves to install the piston ring.
Overhaul - A set of works to restore the condition of the unit, which consists of a complete disassembly, inspection of all elements, subsequent assembly using original or new elements and making all adjustments necessary for reliable operation.
Crankcase - The lower section of the engine that houses the crankshaft. Includes bottom section of cylinder block and oil pan.
Valve mechanism - The engine mechanism used to actuate the valves. Includes all elements, from the camshaft to the valves.
Crankshaft - The main rotating element that runs along the crankcase of the engine and is equipped with offset connecting rod journals to which the connecting rods are connected, and main journals that serve as its supports. Converts the reciprocating motion of the pistons into rotational motion.
Bearing Ring - The inner or outer ring of a bearing that has a contact surface/track for the balls or rollers of the bearing.
Set for measuring clearances in plain bearings Plastigage - A set, the main element of which is a thin plastic thread. Threads are available in various sizes. The scheme of application is approximately the following. The thread is placed along the neck of the bearing and is crushed during the assembly of the mating elements. The mating pair of elements is then disassembled and a thread width measurement is taken to determine the radial clearance between the journal and the bearing. Typically used to measure clearances in crankshaft main and connecting rod bearings.
Crankshaft Kit - Reground or rebuilt crankshaft and new main and connecting rod bearings.
Contact Paint A blue pigment, in solution, used to define the area of contact between two surfaces. Contact paint is typically used to determine the width and location of the contact patch between the bevel and valve seat. Usually it is a blue dye.
Taper - Gradual reduction in the diameter of a shaft or hole. In an engine cylinder, taper usually characterizes uneven wear, more at the top than at the bottom.
Main Bearings - Bearings that support the crankshaft. Main bearing shells can be grooved or babbitt coated.
Connecting Rod Bearing Cap - The part of the connecting rod assembly that secures 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 by nuts or bolts, which in turn hold the bearing shells or form the bearing surface themselves. Grease is injected through the caps.
L
Lacquer coating - Very smooth, vitreous «film», which occurs on the walls of the cylinder during engine operation.
M
Cuff - A seal that prevents oil from escaping beyond a predetermined zone. 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 oil from entering the cylinder walls and into the combustion chamber.
Oil Gallery - A large passage in the cylinder block that carries pressurized engine oil.
Tap - A tool used to cut threads in a hole.
Machining - The operation performed on the machine to remove metal from the surface of a metal element.
H
Carbon deposits - Hard or soft black deposits present in the combustion chamber, on spark plugs, under piston rings, on and under valve heads.
Pilot Bearing - Small bearing mounted in the center of the flywheel (or at the rear end of the crankshaft) and serving as a support for the day of the front end of the input shaft of the gearbox.
Incomplete block of cylinders - The block of cylinders assembled with a crankshaft and piston group and, usually, with a camshaft,
ABOUT
Axial clearance - A value that characterizes the possibility of mutual movement of two elements in the longitudinal direction. When applied to the crankshaft, this is the distance that the crankshaft can move in the cylinder block in both directions.
P
Valve resurfacing - Restoring the shape of a valve using special equipment.
Reduced Oversize Bearings - Bearing shells with a reduced diameter used when using a crankshaft with reground journals.
Piston - A cylindrical element connected to a connecting rod that reciprocates in the cylinder when the crankshaft rotates. When the charge of fuel burns out, the piston transfers the force of the expanding gases to the connecting rod, and that, in turn, to the crankshaft.
Piston Ring - A split ring that fits into a groove in the piston. The rings are in contact with the walls of the annular groove, as well as with «mirror» cylinder, while sealing the gap between the piston and cylinders. 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 attach the piston to the upper end of the connecting rod.
Press fit - A tight fit between two elements that requires considerable force to assemble these elements. Also referred to as an interference fit.
Bearing Shell Diameter Allowance - An allowance that is provided on each bearing shell to ensure that the back of the shell is in full contact with the housing bore when assembling the motor.
Burn-in - The period of operation between the time when new or remanufactured elements are installed and the time when the elements wear down to the state of providing the correct settlement. To ensure that the break-in is to ensure the correct fit, it is recommended to drive at a reduced speed during the prescribed run, changing it.
Lapping of valves - Grinding the chamfer of the valve and its seat using a lapping fin.
R
Bearing Radial Clearance - The clearance between the shaft and the running surface of the bearing, measured in the radial direction. This is the place to inject the lubricant.
Crank radius - The amount of displacement of the connecting rod journal of the crankshaft.
Reaming - Refining, enlarging or improving the surface of a hole with a suitable tool called a reamer.
Camshaft - The shaft of the engine, on which there is a series of cams for driving valve mechanisms. The camshaft is driven by a belt/chain or gear drive.
Boring - The operation of machining an engine cylinder to bring its diameter to a prescribed size.
Coolant 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 the element when unloaded, 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 minor delay.
Segmented Key - A key with a rounded underside (side view).
Saddle - The surface on which the «sits down» other element For example, the valve seat is the element that the valve chamfer mates with
Deburring - Removing Burrs (sharp edges and burrs) from liners and working surfaces of bearings.
Trip - A type of wear in which there is a transfer of material between elements moving relative to each other. It appears in the form «ripples» or grooves on mating surfaces.
Static balance - The balance of an object when it is stationary.
Compression ratio - The ratio between the volume of the 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 close the casting holes for the coolant passages in the engine block.
Bearing Knock - Noise generated when an element is moved in a loose or worn bearing. Knocking in connecting rod or main bearings is due to too much radial clearance or lack of lubrication.
Crackers - Elements that hold the valve spring plate on the valve stem.
T
Follower - An element that is in contact with the camshaft cam and serves to transmit movement to the rest of the valve train.
At
O-Ring - An O-ring made from a special rubber-like material. To ensure tightness, the sealing ring is inserted into the 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 increased end play or crankshaft movement back and forth.
Fatigue - The failure of a material over a large number of load-unload cycles. The first sign of fatigue is cracks, followed shortly by rupture.
Mounting Marking - Small (for example, skewered) dot 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 that the piston travels when moving from top dead center to bottom dead center or vice versa.
C
Scratches - Damage to the surface «mirrors» cylinder, which can result from the movement of solid particles along the walls of the cylinder piston rings.
H
Cast iron - An alloy of iron and carbon (over 2%), used for making blocks and cylinder heads because it is relatively inexpensive and has good casting qualities for casting into complex shapes.
W
Connecting Rod - A lever that connects the crankshaft journal to the piston.
Connecting Rod - The part of the crankshaft to which the connecting rod is connected.
Neck - The part of a rotating ox that rotates in a bearing.
Stud - A metal rod with threads at both ends.
Key - A small piece of metal inserted into corresponding slots in two mating elements (for example, when pressing a gear onto a shaft) and preventing mutual angular movement of these two elements.
SCH
probe (probe set) A thin, hardened steel strip of precise thickness used to check gaps between elements.
YU
Piston Skirt - The part of the piston below the piston ring area and the piston pin hole.