Main bearing clearances must be always zero at the bottom, if they are not, the crankshaft is out of alignment. Effect bearing misalignment in deflection value- 1. if two intermediate bearings are placed too high from the center line crank throw will opens in tdc and closes in bdc.(Ie t<b) 2. one of the bearing is mis
aligned, t>b. deflection is taken with maintaining same jacket water temperature. and vessel afloat, Place the dial gauge at the punch mark set dial gauge at zero before bdc in cam-side and rotate iston towards tdc. vertical misalignment and horizontal misalignment is calculated. closing of crank throw is taken negative and opening is positive. turning gear must not be stopped during taking deflection, if stopped turn reverse to unload the gear teeth.
aligned, t>b. deflection is taken with maintaining same jacket water temperature. and vessel afloat, Place the dial gauge at the punch mark set dial gauge at zero before bdc in cam-side and rotate iston towards tdc. vertical misalignment and horizontal misalignment is calculated. closing of crank throw is taken negative and opening is positive. turning gear must not be stopped during taking deflection, if stopped turn reverse to unload the gear teeth.
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