12.What all clearance taken in Main engine

MAIN BEARING CLEARANCE:

            This clearance is taken between journal and upper bearing shell.

Methods used:

By using Telescopic or Swedish Feeler Gauge:

• This is the method mostly used in MAN B & W engines. 
• First bring the crank web in horizontal position for easy access. 
• The clearance can be measured by extending feeler gauge into the gap between journal and upper shell of bearing. 

By using Dial type depth gauge:

• This is also used in MAN B & W SMC-C engines.
• The lube oil pipe connection screw hole is in the bearing keep which can be accessed from the hole on the bearing shell.
• Insert the depth gauge into the groove and measure the clearance.

CRANKPIN OR BOTTOM END BEARING CLEARANCE:

·         Turn the crank to BDC

·         Measure the clearance between bottom of the bearing shell and crank pin in both the sides by means of feeler gauge.

CROSSHEAD BEARING CLEARANCE:

            All clearances are taken by feeler gauge.

Crosshead pin bearing clearance:

            This is taken between crosshead pin and upper shell of bearing by using feeler gauge. 

Guide shoe clearance:

·         There are two clearances are measured here.

·         One clearance is taken between guide bar and guide shoe by feeler gauge in port and starboard side.

·         Second clearance is taken between guide bar and guide shoe by feeler gauge in forward and aft side. 

Crosshead pin thrust clearance:

            This is taken between thrust piece and crosshead pin by feeler gauge