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Filter. A device to remove dirt and other impurities from air, oil, or water.
Fit. The desired positive or negative clearance between the surfaces of two machined engine parts.
Flash point. The temperature, degrees F, to which oil must be heated before the oil vapor over the oil will ignite when a small flame is passed across the surface of the oil.
Fluctuation. Variation in value, such as of pressure or velocity.
Flywheel. The wheel on the end of the crankshaft that gives the crankshaft momentum to carry the pistons through the compression stroke.
Foot pound. Unit in which, work is measured; it is equivalent to the work of raising one pound vertically a distance of one foot or of moving an object ore foot against a resistance of one pound. Abbreviated ft-lb.
Four-stroke engine. An engine operating on a cycle which is completed in four strokes, or two revolutions of the crankshaft.
Framing. The part of an engine between the cylinders and the bedplate; the crankcase.
Friction. The resistance to relative motion between two bodies in contact.
Friction horsepower. The power consumed within the engine from friction between its parts.
Fuel injector. The device which sprays the fuel into the cylinder.
Fuel knock. A noise produced in the cylinder of a diesel engine during combustion, usually when the fuel oil has a low ignition quality.
Fuel pump. The pump that delivers the fuel to the injector.
Fulcrum. The support on which a lever turns.

Internal-combustion engine glossary

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