Appendix B—Mechanical Specifications for Model WFD551
Clearances and Dimensions
Distance Piece Connections and Piston Rod Packing Orientation
*Dimensions for honing are included with new bushings (install bushings before honing).
Piston Clearance ‘X’ (Cold)
a
Specifications
“X” Inches (Millimeter)
Minimum
Maximum
0.065 (1.65)
0.077 (1.95)
a
The distance from the bottom of the head to the top of the piston.
CAUTION: Always relieve pressure in the unit before attempting any repairs.
Model
Packing
Arrangement
Conditions Service
Distance Piece Opening, 1/4" NPT
V-Rings Point
Upper
Lower
Upper Lower
All models
WFD551
Specification A
Inlet pressure:
above 15 psia
1) General
gas transfer
Plugged to allow
the distance piece
pressure to reach its
own level.
Pipe to drain or
vent with a shut-off
valve. Distance piece
must be drained
weekly to prevent an
accumulation of oil or
condensate.
Spring
Spring
2) Highly
toxic gases
Pressurized via an
external gas source
to a pressure below
suction pressure and
above atmospheric
pressure. Or, vented to
atmospheric pressure (at
a suitable location) or to
a low pressure flare.
Description
1st Stage
2nd Stage
Clearance: Conrod bearing to crankshaft journal
0.0013/0.0033
Clearance: Wrist pin to wrist pin bushing* (max)
0.001
Cylinder bore diameter (max)
2.515
4.015
Cylinder finish (RMS)
16
Piston ring radial thickness (min)
0.090
0.082
Clearance: Oil pump adapter shaft to bushing* (max)
0.0036
Crankshaft end play (cold)
0.002/0.003
Flywheel runout at O.D. (max)
0.020
Clearance: Crosshead to crosshead guide bore (max)
0.008
Crosshead guide bore finish (max)
32 RMS (Limited number of small pits and
scratches are acceptable)
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