1. Scope--This SAE Recommended Practice applies to flywheels and flywheel-starter ring gear assemblies used with internal combustion engines of the spark ignition and diesel type equipped with a governor or speed limiting device. Engine sizes are those capable of using SAE No. 6 through SAE No. 00 flywheel housings.

This document applies to methods used to determine the rotational speed capability of flywheels for stresses imposed by centrifugal forces only.

1.1 Purpose--This document is intended to establish maximum allowable rotational speeds for flywheels under centrifugally imposed stresses.

1.2 Exclusions

1.2.1 GENERAL--This document does not encompass the selection of flywheel profile, materials, and manufacturing methods.

The influence of the following items which may reduce the speed capability of the flywheel below acceptable speed limit are not considered in this document and must be evaluated separately:

a. Material fatigue

b. Material yielding before the limiting speed or burst speed is reached

c. Clutch heat loading and cracks

d. Additional loading due to drive coupling members assembled to the flywheel or due to the flywheel drive system type used

1.2.2 APPLICATION SPEED RESTRICTIONS--This document does not apply to any application where the engine is not equipped with a governor or speed limiting device or when overspeed (No.) may exceed 50% above the rated engine speed (NR); (No. 1.5NR).

1.2.3 FIELD USAGE AND REWORK RESTRICTIONS--This document does not apply when the following is done without the approval of the engine manufacturer:

1.2.3.1 The flywheel profile is reworked for another application.

1.2.3.2 The flywheel clutch friction face is refaced beyond the material removal limits recommended by the engine manufacturer.

1.2.3.3 The engine and flywheel package are used in an application other than the one for which it was originally designed.

1.2.3.4 The flywheel is removed from the original engine and installed on another engine where the rated speed or overspeed requirement is higher.