Heavy Duty Balanced Opposed Compressors - Ariel Corporation

Appendix A Ariel Fasteners and Torques For Models: JGH:E:K:T
Recommendations for Torque Accuracy
1. Qualified personnel must use a properly calibrated torque wrench to correctly torque fasteners.
2. Determine torque wrench accuracy range. Most torque wrenches are not accurate over their
entire range.
3. Clean and de-burr all threads before assembly.
4. Tighten all multi-bolt assemblies in steps (optional for Grade 5 cap screws). Snug opposing pairs
of cap screws until all are snug. Next, tighten each cap screw to 25% of full torque in the same
pattern. Repeat this step for 50%, 75%, and 100% of full torque. For main bearing stud nuts and
connecting rod bolts, repeat the 100% step to verify proper pre-torque of fasteners prior to the
final partial turn.
5. Always apply a steady slow force to a torque wrench, and stop immediately when the wrench
clicks; do not jerk it. Jerking a torque wrench may apply up to one and a half times the wrench
torque setting.
6. Perform final tightening with a torque wrench. Do not tighten fasteners with a ratchet or impact
wrench, and then "check" the torque with a torque wrench.
7. Do not double tap a torque wrench; it increases the set torque significantly.
8. When checking the torque of a tightened fastener, set torque wrench to required torque, then
apply a slow steady force until the wrench clicks.
9. When finished, reset torque wrench to its lowest setting to relax the spring and help retain accuracy.
A torque wrench left in a high setting stresses the spring and decreases accuracy with time.
10. Do not break fasteners loose with a torque wrench; it may overload the wrench and/or destroy
calibration.
11. To determine the torque wrench setting when using a torque multiplier on larger fasteners, divide
the desired fastener torque by the multiplier actual mechanical advantage, not the design
mechanical advantage. Example: An X4 torque multiplier, model TD-1000 has a design mechanical
advantage of 4.0, but an actual mechanical advantage of 3.6.
12. For hard to access fasteners requiring a
boxed end or crowsfoot adapter with a torque
wrench, the torque wrench setting is not the
actual torque applied to the fastener, unless
the adapter is 90° to the torque wrench. The
ratio of actual fastener torque (Ta) with the
A
L
wrench torque setting (Tw) is a function of the
length the adapter adds to the torque wrench
(A), and the location of the applied force.
Tw = Ta x [L ÷ (L + A)]
Tw = Torque wrench setting, lb x ft or N·m.
Ta = Torque required at fastener, lb x ft or N·m.
Force
FIGURE A-1 Torque Wrench with Angled Adapter
L = Length of wrench, ft or m (from square drive end to center point of force on handle).
A = Wrench length added by adapter, ft or m (measured through end of adapter on a line parallel
to the center line of the wrench).
NOTE: Lb x In ÷ 12 = Lb x Ft
13. When studs are specified for cylinder applications, tighten nuts to the same values as cap screws
in similar applications.
14. Install pipe threads and main cap plugs using Loctite 565 thread sealant. Synthetic oils may
require Loctite 545 and Loctite Activator 7649 (N).
These are general guidelines for proper torque wrench use. Call a torque wrench dealer for details.
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