Rotax 447 - Rotax  reduction drive removal.

Rebuilding manual for the 447 Rotax aircraft engines.

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Rotax Reduction Drive-Removal .

Tools Required.
13 mm socket
() mm socket
ratchet
() mm allen wrench
propane torch
hammer
Oil drain pan
Rotax reduction drive gear puller
Johnson bar
12 inches rope
Spark plug wrench

Procedure

For engine disassembly, or reduction drive repair it is necessary to remove the reduction drive from the engine assembly. First drain the oil from the gear drive assembly, using a () mm wrench to remove the drain plug from the bottom of the gear drive. With a ratchet and socket/wrench and loosen the six, 13 mm nuts, retaining the drive to the adapter plate. With all the nuts loose remove the top 4 in a gear down assembly, or the bottom 4, in a gear up assembly.

Grasp the drive by the output shaft, and pull outwards on the drive. On older model drives it may be necessary to turn the engine over while pulling out to allow the gear to clear the gear oil slinger
This slingers no longer used and should be discarded.
With the drive removed it is next necessary to remove the adapter plate. To allow access to the 4 allen head screws securing the adapter plate to the gear drive, it maybe necessary to remove the 4 studs used to hold the gear drive to the adapter plate. To do this screw one of the 13 mm nuts removed from the studs onto the stud, until it is near the bottom of the threads. Now install another nut onto the stud until it locks against the first nut. Now using 2, 13 mm wrenches tighten the nuts against each other. Then come in and using a 13 mm wrench remove the stud, by turning counter clockwise on the first nut. Repeat for the remaining studs as necessary.

With the studs removed, use a hammer and sharply wrap each of the allen head retaining screws. This will help shock them loose from the Blue Loctite used to help retain them. Before attempting to remove the allen screws it is suggested that you use a propane torch or B tank to heat the crankcase, in the area of the threads holding the bolts.

With the bolts shocked, the crankcase thread areas heated, use an allen wrench to remove the four retaining screws. If you strip the heads of the screws, use a pair of VICE GRIP style pliers to grab the outside of the screws, to aid in removal.

Rotax Reduction Drive- Gear Removal

Tools Required Tools Required
.() socket
ratchet
Rotax gear puller
12" piece of rope spark plug wrench

Procedure

Using a spark plug wrench remove the spark plug from the PTO side cylinder. Turn the engine over clockwise until it is past TDC and the piston is positioned about 1 inch down in the cylinder. Take your 12 inches of rope and feed it through the spark plug hole until 8 inches or so are located in the combustion chamber.

Turn the engine over counter clockwise, until it locks up. Place your () mm socket onto the bolts retaining the gear to the crankshaft. Using a Johnson bar turn the socket counter clockwise until the bolt comes free. Remove the bolt, washer, and impeller, if so equipped.

With the bolt removed, remove the rope from spark plug hole. Turn the engine over until the PTO piston is at TDC. Rotate the crankshaft counter clockwise until the piston is approximately 1 inch down in the cylinder. Again install your rope. Bring the piston up until the engine locks up.

Install your Rotax gear puller into the threaded section of the gear being sure to thread the outer puller half of the puller all the way in. Then by hand turn

Install the puller bolt in until it butts against the crankshaft end. Install a () mm socket onto the end of the puller bolt, then using a Johnson bar turn the bolt in a clockwise direction until the gear comes free of the crankshaft.

Reduction drive installation B drive

Clean thead of hex head. screw  1.2-20 UNFx50(#2), cone in drive gear (#4) and taper of crankshaft (#1) with suitable degreasing agent. Lock crankshaft using fixation pin # 876 640. Place drive gear (#4) on crankshaft taper and attach with hex hd screw 1.2-20 UNFx50 (#2), lock washer (#7) and washer (#6) with face of washer towards crankshaft and tighten screw to 80 NM (530 inch lbs.)
*Carefully remove existing gasket(#l 5) and put on something clean to rest on.  Apply grease on a few spots of o dng groove in gear housing(#l 3) and place o ring (#14) in position *Clean sealing face of gear housing(#13) and crankcase(M), apply Loctits 680(L) and fit gear housing(#l 3) in correct position. *Basically, there are two possible positions in which the ddve can be installed: Version SZ - prop shaft offset to cylinders Version SS - prop shaft offset toward engine base *For fitting the gear housing the the engine apply bearing grease(F) on support face of hex collar screws M8x65((#l 6) and tighten to 24NW210inibs. Put greass on the support face of the screw head to prevent seizing. *Check dowel sleeves (#l 7) for proper fit and piece gasket(#l 5) into position. Gasket(#l 5) has to be fitted in dry condition to warrant optimum sealing
*Carefully fit gear cover(#l 2) onto gear housing(#l 3). When fitting the gear cover pay attention for easy engagement of the mating gears, and on a gearbox with reduction ratio 3.0 mind the extra bearing of the drive gear(#S) in the gear cover *Fasten gear cover to gear housing with the 2 hex hd screws M8x65(#l 0) and the 2 hex hd. screws MBxl 25(#l 4) along with the lockwashers and tighten screws in crosswise sequence to 24NM/212 in lb. Afterwards add the screws MBxl 1 0 (#l 5) with lo6kwasher AB(#l 1) and tighten screws to 24NW 212 in lb as well. *Remove crankshaft locking pin (#8) *Depending on the position of gearbox, fit magnetic plug (#16) and sealing ring (#17)(torque = 24NM/212 in lb) and vent screw (#18) with sealing ring (#l 9)(torque = 6NM/53 in lb)
Initial quantity of oil: SZ= 330 cu cm/.7 pt SS= 300 cu cm/.63 pt *Basically fill gearbox with oil until oil emerges on the lower oil level lug (#20). Fit oil level plug (#20) along with sealing ring.  Use SAE 140 EP or SAE 85W - 140EP. API classification GL5 or GL6. *Wire secure (D) filling plug (#l 8), level lugs (#20) and drain plug (#16) Check gearbox for tightness before/and after  run. *Prop flange is furnished with 6 tapped holes for 8mm bolts and 6 holes for 1/4" bolts. Prop bolts are not supplied by ROTAX. *For spare parts numbers see previous drive breakdown.
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