piston slap

piston slap

n
(Automotive Engineering) the characteristic sound of a seriously worn piston in a cylinder (usually of the engine of a motor car)
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References in periodicals archive ?
The piston pin is offset 0.3 degrees from the centerline to reduce 'piston slap' against the cylinder wall, minimizing NVH
et al., "A Numerical Model of Piston Secondary Motion and Piston Slap in Partially Flooded Elastohydrodynamic Skirt Lubrication," SAE Technical Paper 940696, 1994, doi:10.4271/940696.
Mechanical noise mainly includes piston slap noise, air valve knock noise, gear meshing noise, and fuel injection pump noise.
Instead of it being located on a crank, the clever design means that the piston slides absolutely vertically on a geared rail so that piston slap is zero.
The pistons have an offset piston pin and extended piston skirt that reduces piston slap and thus engine noise levels, Sugar said.
It is used to take out the piston slap when placing in new rings.
This causes the piston to shift in the opposite cylinder wall just before top dead center greatly reducing piston slap (aka: noise).
When mechanics say: "That noise could be a rod or main knock, piston slap, or a bad lifter."
"Among the signals coming from the cylinder are those that result from piston slap, which occurs in an engine because of the changing angle of the crankshaft as it revolves through a full stroke," Lyon said.
This causes the piston to shift to the opposite cylinder wall just before top dead center, greatly reducing piston slap.
This has also reduced engine noise, since closer tolerances yield less piston slap at low load and cold start conditions.
Piston slap has been reduced by optimizing the clearances between the single-piece piston and the cylinder and the piston skirt features a molybdenum coating that improves fit within the cylinder.