Other Order Engine Vibrations

0.5 Order (E0.5) -The camshaft(s) rotate at half the crankshaft speed. A camshaft or camshaft bearing problem would result in a 0.5-order engine-speed-related vibration. For example: if the engine speed were 2000 RPM, the camshaft speed would be 1000 RPM. Some newer engines have variable cam timing. The cam timing is adjusted by a camshaft phaser attached to the end of the camshaft. The camshaft phaser could be responsible for a 0.5-order engine-speed-related vibration.
On four-stroke engines, each cylinder is fired once for every two revolutions of the crankshaft. A single cylinder misfire would cause one disturbance every two revolutions of the crankshaft. This is a 0.5 order vibration. This type of vibration will be accompanied by some sort of engine driveability issue and possible a lack of power from the engine. For example: if the engine speed was 2000 RPM, the vibration caused by a single cylinder misfire would be 1000 RPM.
Cylinder/4 order - A bank-to-bank EGR or air-fuel ratio variation can cause the cylinders on one bank of a V or opposed cylinder configuration engine to misfire. This would affect half the engine's cylinders resulting in a vibration which equals the number of engine cylinders divided by 4. A V8 engine with a bank-to-bank EGR or air-fuel ratio variation problem would have a second order vibration. For example: if the engine speed was 2000 RPM, the vibration caused by a bank-to-bank EGR or air-fuel ratio variation would be 500 RPM.