Appendix B—Mechanical Specifications for Model WFD551
Mechanical Specifications
Bolt Torque Values
Head Bolt Torque Sequence for WFD551
1
2
3
4
5
6
7
8
9
10
11
12
Flywheel side
Water outlet
connection
Water outlet
connection
Pressure gauge connection
Pressure gauge connections
Pressure equalization connection
Note: Torque head bolts in the sequence shown above. All bolts are inserted through the top of the head.
Specification
All Models 551
Bore of cylinder, inches (mm)
first stage
4.0 (101.6)
second stage
2.5 (63.5)
Stroke, inches (mm)
4.0 (101.6)
Piston displacement, cfm (m
3
/hr)
minimum @ 400 RPM
11.6 (19.7)
maximum @ 825 RPM
24.0 (40.8)
Maximum working pressure, psig (bar g)
1,000 (68.9)
Maximum brake horsepower, kW
45 (33.6)
Maximum rod load, lb (kg)
7,000 (3175)
Maximum outlet temperature °F (°C)
350 (177)
Approximate bare unit weight, lb (kg)
815 (369.7)
Connecting rod bolt
40 ft•lb
Bearing carrier
40 ft•lb
Bearing cover
40 ft•lb
Crankcase inspection plate
9 ft•lb
Crosshead guide
65 ft•lb
Cylinder to head
1,2
65 ft•lb
Valve cover plate bolt
37 ft•lb
Valve holddown screw
2
40 ft•lb
Piston locknut
45 ft•lb
Socket head piston screw
8 in•lb
Valve / unloader cap (w/ O-rings)
25 ft•lb
1
Preliminary tightening: Snug all head bolts in the
sequence shown below. Final torque: Torque all head
bolts in the sequence shown to the listed value.
2
Re-torque to the value listed above after 2 to 5 hours
of running time.
22
