Search results
Results from the WOW.Com Content Network
An overhead valve engine, abbreviated (OHV) and sometimes called a pushrod engine, is a piston engine whose valves are located in the cylinder head above the combustion chamber. This contrasts with flathead (or "sidevalve") engines , where the valves were located below the combustion chamber in the engine block .
SOHC design (for a 1973 Triumph Dolomite Sprint) . The oldest configuration of overhead camshaft engine is the single overhead camshaft (SOHC) design. [1] A SOHC engine has one camshaft per bank of cylinders, therefore a straight engine has a total of one camshaft and a V engine or flat engine has a total of two camshafts (one for each cylinder bank).
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.
Most modern pushrod engines have two valves per cylinder, while many OHC engines can have three, four or even five valves per cylinder to achieve greater efficiency and power. Recently, however, GM has begun offering a pushrod V6 with VVT, and Cummins' ISB is a 4-valve pushrod straight-6. The GM 3900 was the first mass-produced pushrod engine ...
The ratio is determined by the ratio of the distances from the rocker arm's pivot point to the point where it touches the valve and the point where it touches the pushrod/camshaft. A rocker ratio greater than one essentially increases the camshaft's lift. Current automotive design favors rocker arm ratios of about 1.5:1 to 1.8:1.
Most pushrod engines do not have superior power to weight ratios, OHC race engines have vastly superior power to weight ratios compared with pushrod race engines. In order to make anything stating that pushrod engines have superior power to weight ratios accurate you would have to list that there are many exceptions, which really makes the ...
The High Value engine family from General Motors is a group of cam-in-block or overhead valve V6 engines.These engines feature cast iron blocks and aluminum heads, and use the same 60° vee bank as the 60° V6 family they are based on, but the new 99 mm (3.90 in) bore required offsetting the bores by 1.5 mm (0.059 in) away from the engine center line.
Though it was designed as a pushrod engine, it was advanced for the time. [1] The pushrod version of the Lancia boxer was only ever used in the Flavia, and its derivatives including the Lancia 2000. In 1976, a new overhead cam engine based on a similar layout was designed and brought into production in 2 and 2.5-litre displacements for the Gamma.