Things to check before installation begins:
Engine shaft size
Most of the time, general purpose clutches are mounted directly on the engine shaft. If the installation is not on an engine shaft, please make sure that the tolerances are close enough to provide a snug fit between the bore of our clutch and the shaft. (All engine manufacturers should produce shafts within the required tolerances.) Also, a standard rule of thumb is that the minimum diameter of the shaft for one piece designs is also the minimum amount of shaft engagement. (Two-piece designs would require shaft engagement in both pieces.) The engine shaft step radius needs to be smaller than the chamfer on the clutch or the clutch will not seat properly. If interference occurs, a spacer with a proper chamfer is required.
Direction of rotation
We manufacture our units to operate either clockwise or counter-clockwise. They can be mounted with the pulley toward the engine or they can be mounted with the pulley away from the engine. This mounting is critical because this determines which direction the leaf springs are orientated. If springs are not run in tension, they could suffer premature failure because they will be running in compression. If the torque required from the clutch is low enough, (less than 75%) and vibration and inertia are low, it is not as critical that the springs be mounted in the correct configuration.
Torque tab restraint
Prior to installation, it is critical to determine the torque tab placement. The function of the torque tab is to keep the lead wires from pulling out of the clutch due to the bearing drag. This torque tab should have a freedom of movement both axially and radially of about 1/16 of an inch. The simplest type of torque tab restraint is some type of "u" bracket that captures the torque tab, but does not grab it firmly. In heavy vibration applications, a larger surface area is required to prevent notching of the torque tab and the restraining pin or bracket.
Key length and height
In many of the clutches, the key does not go all the way through the clutch. Therefore, the key length can only be as long as the keyway length within the rotor. Please check this before installation. In some clutches, the bearing inner race may be exposed on the top of the keyway. In this case, the key needs to be slightly undersized in this area so it does not force itself against the bearing inner race.