(18) M8 Rotax Cylinder Embase Nut

Full description: what is the purpose of this piece?

The base nut is much more than just a piece of hardware; It is a motor safety component:

1. Maintenance of compression: By tightening the cylinder on the low engine studs, this nut ensures that the block remains perfectly motionless despite the internal combustion pressure.

2. Sealing the seal plane: Uniform tightening with these nuts prevents air-gasoline mixing leaks at the base, which would avoid fatal air intakes (engine tightening).

3. Thermal and mechanical resistance: Made in a high-class steel, it is designed not to stretch despite the repeated engine coolant cycles.

4. Standardized format: Her size M8 With a wide base distributes the tightening force on a larger surface of the aluminum of the cylinder, thus avoiding to mark or distort the room.

? Michel's trick

"Listen to me well: the base nut, it's not at piv! If you are overwhelming, you break the stud or you sail your base. If you do not squeeze enough, you will take an air intake and your engine will get carried away alone before Tighten. My Pro Council: uses always a torque wrench. And do not forget: we replace the nuts if they start to be rounded, because a key that ripe on a burning motor is the best way to finish the emergency room! "

? Tuto: Tightening and maintenance

1. Cleaning: Before screwing, checks that the threads of the studs are clean and dry. A fat mesh can distort the tightening value.

2. Cross clamping: To avoid putting the cylinder through, tight the 4 nuts gradually following a diagonal (crosswise).

3. The tightening torque: For a Rotax Max, the couple recommended is 24 nm. No need to put on the Loctite, the tightening to the couple is enough.

4. Control: After the first rolling session with a new or revised engine, restores a small cold key. With heat, metals work and slight tightening is sometimes necessary.