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Although an overhead camshaft (OHC) engine also has overhead valves, the common usage of the term "overhead valve engine" is limited to engines where the camshaft is located in the engine block. In these traditional OHV engines, the motion of the camshaft is transferred using pushrods (hence the term "pushrod engine") and rocker arms to operate ...
This reduced inertia in OHC engines results in less valve float at higher engine speeds (RPM). [1] A downside is that the system used to drive the camshaft (usually a timing chain in modern engines) is more complex in an OHC engine, such as the 4-chain valvetrain of the Audi 3.2 or the 2 meter chain on Ford cammers. Another disadvantage of OHC ...
Roller rockers can also be used in overhead cam engines (OHC). However, these generally have the roller at the point where the cam lobe contacts the rocker, rather than where the rocker contacts the valve stem. Some OHC engines employ short rocker arms, also known as finger followers, [2] in which the cam lobe pushes downward on the back of the ...
Pushrods are long, slender metal rods that are used in overhead valve engines to transfer motion from the camshaft (located in the engine block) to the valves (located in the cylinder head). The bottom end of a pushrod is mated to a lifter, upon which the camshaft makes contact. The camshaft lobe moves the lifter upwards, which moves the pushrod.
The lobed camshaft rhythmically presses against the lifter, which transmits the motion to the engine valve in one of two ways: through a pushrod which actuates the valve via a rocker mechanism (in an overhead valve (OHV) engine); via direct contact with the valve stem or rocker arm (in an overhead camshaft (OHC) configuration).
2.5 L; 152.2 cu in (2,494 cc) inline-5, with two (pushrod-actuated) valves-per-cylinder and indirect fuel injection from either Bosch or Spica. 88 mm × 82 mm (3.46 in × 3.23 in). This engine is a five-cylinder version of the 2-litre HR488, and also uses KKK turbochargers. Applications:
Also pushrod engines almost always make less power and torque from a given displacement, compare just about any engine you can find: BMW M3 - 81.875 ft-lb/l, LS7 - 67 ft-lb/l. Also compare the output of the OHC Ford engines to the GM pushrod engines, the Fords have higher torque output for a given displacement.
At the beginning of 1984, Ford Pinto engine displacement range switched from 1.3/1.6/2.0 to 1.6/1.8/2.0. The newly introduced 1.8 L engine used the 2.0 L crankshaft, so to uniform engine parts for the whole range after dropping the 1.3 L — the 1.6 L was redesigned to also take the 2.0 L crankshaft which had a 76.95 mm (3.030 in) stroke.