07-09-2016, 12:08 PM
1453454620-partsbearingsgearing.ppt (Size: 7.84 MB / Downloads: 25)
Cylinder Barrel
Chrome-molybdenum or nickel-molybdenum steel
Used to guide and seal piston and to mount cylinder assembly to head
Barrel threads into head to form cylinder assembly
Cylinder Walls
Inside surface of cylinder barrel is honed to a controlled amount of roughness
Rough enough to hold oil film but smooth enough to minimize friction and wear
Plain steel cylinder walls are not treated to prevent wear or corrosion
Nitrided cylinder walls are hardened to reduce wear but still rust as easily as plain steel walls. Nitriding is exposing the cylinder wall to ammonia at high temperatures and it hardens the wall to a thickness of approximately .005”
Crankshaft
Changes reciprocating motion of pistons into rotating motion to drive propeller
Constructed of chrome-nickel-molybdenum-steel
May be one piece or as many as three separate pieces
The propeller mounts to the front of the crankshaft using a spline, taper, or flange
The crankshaft rotates within the crankcase and is supported by main bearing journals
Crankshaft throws or crankpins are off center and account for the reciprocating motion of the pistons