overload clutch (slipper clutch) still incorporate the torsional  shock absorption. This design is similar to the system with  overload clutch, but without free rotation. For this reason, the  friction torque method cannot be applied on engines without  the overload clutch. with the O-ring (4) and the oil lines. Remove the inner parts of  the oil tank, such as the baffle insert (5) and the partition (6).  Clean oil tank (8) and inner parts (5, 6), and check for damage.  Be aware that incorrect assembly of the oil tank components  can cause engine faults or engine damage. Replace the drain  screw with a new sealing ring (7) and tighten to 25 Newton  meters (Nm) (18.5 ft/lb) and safety wire. Reassemble the oil  tank by following the same steps in reverse order. Fit the crankshaft with a locking pin.  [Figure 11-34]  With  the crankshaft locked, the propeller can be turned by hand  15 or 30 degrees, depending on the profile of the dog gears  installed. This is the maximum amount of movement allowed  by the dog gears in the torsional shock absorption unit.  WARNING: Ignition OFF and system grounded. Disconnect  negative terminal of aircraft battery. Turn the propeller by hand back and forth between ramps,  taking into consideration the friction torque. No odd noises or  irregular resistance must be noticeable during this movement.  Attach a calibrated spring scale to the propeller at a certain  distance (L) from the center of the propeller. Measure the  force required to pull the propeller through the 15 or 30  degree range of free rotation. Calculate friction torque Nm by  multiplying the force Newton’s (N) or pounds (lb) obtained  on the spring scale by the distance the scale is attached from  the center of the propeller (L). The distance measurement and  torque measurement must be in the same units either standard  or metric and cannot be mixed up. The friction torque must  be between a minimum of 25 Nm and maximum of 60 Nm  (18.5 to 44.3 ft/lb). A calculation example is as follows: Friction Torque (FT) = Length (meters) × Newtons (torque) FT = .5 meters × 60 Newtons FT = 30Nm Remove crankshaft locking pin and reinstall plug with new  gasket. Reconnect negative terminal of aircraft battery.  If the above mentioned friction torque is not achieved,  The following free rotation check and friction torque check  are necessary only on certified engines and on engines with  the overload clutch as an optional extra. Engines without the  Remove the magnetic plug and inspect it for accumulation  of chips.  [Figure 11-33]  The magnetic plug (torx screw) is  located on the crankcase between cylinder 2 and the gearbox.  This inspection is important because it allows conclusions  to be drawn on the internal condition of the gearbox and  engine, and reveals information about possible damage. If  a significant amount of metal chips are detected, the engine  must be inspected, repaired, or overhauled. Steel chips in low  numbers can be tolerated if the accumulation is below 3 mm  (0.125 in).  [Figure 11-33]  In the case of unclear findings,  flush the oil circuit and fit a new oil filter. Afterwards, conduct  an engine test run and inspect the oil filter once more. If there  are larger accumulations of metal chips on the magnetic plug,  the engine must be repaired or overhauled in accordance with  the manufacturer’s instructions for continued airworthiness.  A detailed inspection of affected engine components must  be performed. If the oil circuit is contaminated, replace the  oil cooler and flush the oil circuit, then trace the cause and  remedy the situation. If the magnetic chip is found to have no  metal, then clean and reinstall. Tighten the plug to a torque  of 25 Nm (18.5 ft/lb). Safety wire the plug and inspect all  systems for correct function. 11-22 Figure 11-34.  Checking propeller gearbox. Figure 11-33.  Inspecting the magnetic plug. Example of minimum torque: F x L = 20N x 0.76m = 15 Nm Example of maximum torque: F x L = 59 N x 0.76m = 45 Nm 0 2 4 6 8 10 12 14 0 2 4 6 8 10 12 14 Length (L) in m Force (F) in N Acceptable Not acceptable Checking the Propeller Gearbox Inspecting the Magnetic Plug Checking the Friction Torque in Free Rotation