Professional
Racing Clutches
The HELIX Racing Clutch range has been designed to satisfy the variety of needs found in the competition market place.
The clutch cover is a one piece Aluminium Alloy of the Lug Drive Design type which has a low moment of inertia, gives the benefit of greater heat dissipation to run cooler whilst also allowing the friction dust to escape.
These clutches are available in the following formats:
- Sintered Rigid Hub
- Cerametallic rigid Hub (Paddle Clutch)
- Cerametallic Sprung Hub (Paddle Clutch)
- Organic Rigid Hub
- Organic Sprung Hub
The format above is the description of the type of drive plate used. The correct unit to be used depends on its use and application together with engine torque. This will assist in determining the clutch diameter and number of plates required. The information offered here will help in making a decision, but if required the technical department of Helix Autosport is available to offer assistance.
- Cerametallic clutches are available 1 & 2 plate versions diameter 184, 200 & 215mm
- Organic clutches are available in 1 & 2 plate versions diameter 184, 200 & 215mm
- Sintered clutches are available in 1, 2, 3, & 4 plate versions ( only available in 140mm & 184mm diameter. )
Drive Plate Material Explained:
Organic
- Best Suited to road applications
- Can be used for light competition work
- More comfort in engagement
- Least prone to judder
- Lightweight = low inertia
- Compact installation
- Available in both rigid and sprung hub formats
Sintered
- Used primarily in race applications
- Compact dimensions
- Lightweight = Low inertia
- Can be used for Rallying application
Cerametallic
- Primarily used for rally applications
- Is also used for race applications especially with a diameter over 184mm
- Can be used for road use where engine torque requires it
- More resistance to high energy input
- Smoother engagement than sintered material plates
- Less prone to judder than sintered material plates
- Available in both rigid and sprung centre formats
The racing clutches are fitted to the flywheel by either:
The preferred / Recommended method
- High quality bolts / mounting studs passing through from the rear of the flywheel.
- These need to be a close tolerance push fit through the flywheel with a locating spigot machined on the rear of the flywheel to prevent rotation of the bolts / mounting studs.
- These are retained by K-lock nuts.
- See relevant clutch diameter section for dimensions and torque figures.
Or by :-
- High quality socket head cap screws ( min tensile 10.9 ) diameter 8mm or 5/16”located through the cover assembly and screwed directly into the flywheel.
- In using this method it is important that a counter bore is used to ensure the shear load
- Through the screw is across the full shank diameter and NOT the thread.
- See relevant clutch diameter section for dimensions and torque figures
Flywheels
These clutches can be fitted to existing cast iron O.E. flywheels but these should not be used above 9000rpm. It is not advisable to modify twin mass / dual mass flywheels except where there is no other option and in which case these should not be used above 8000 rpm
It is recommended that a high quality purpose made steel flywheel be used material to be of 0.35 / 0.45 carbon with a minimum hardness of
The run out of this flywheel when fitted to the crankshaft must not exceed 0.08mm at 76mm radius.
See relevant clutch diameter section for dimensions and torque figures
Fixing Studs / Bolts
Clutch Diameter 140mm. Bolt O ¼” UNF
See 140mm O clutch section , flywheel dimension & details
Clutch Diameter 184mm. Bolt / Stud O 5/16” UNF
See 184mm O clutch section, flywheel dimensions & details
Clutch Diameter 200mm. Bolt / Stud O 5/16” UNF
See 200mm O clutch section, flywheel dimensions & details
Clutch Diameter 215mm. Bolt / Stud O 5/16” UNF
See 215mm O clutch section, flywheel dimensions & details.
Maintenance
It is advised that regular inspection and maintenance is carried out to ensure the clutch operates to its optimum performance.
Pressure plates should be checked for coning and replaced when more than 0.15mm out of flat, otherwise the clutch can drag interfering with clutch release.
Driven plates should be replaced if showing signs of damage or if the minimum thickness has been reached ( see the relevant clutch diameter section for details )
Release Bearings
The release bearings should be a high quality steel caged radius contact ball bearing with a fulcrum diameter of :-
- 48 à 50mm for a clutch of O 140mm
- 48 à 54mm for a clutch of O 184mm
- 52 à 54mm for a clutch of O 200mm & 215mm
On fitting the release bearing it should be arranged so that the bearing is not in contact with the diaphragm spring fingers when the clutch is fully engaged
It is also IMPORTANT that the travel of the bearing when operated is to a controlled distance otherwise damage to the diaphragm spring can occur, this travel can be limited by means of an external stop.
Bearings available
Clutches fitted with an O.E. concentric slave cylinder operating system will require this being replaced with a more robust system and not just a release bearing.
For the fitment of 184mm clutches to BMW vehicles special bearings are available:
- 43-3002 for gearboxes with a 28mm x 10teeth spline
- 43-3003 for gearboxes with a 28mm x 22teeth spline
- 43-3004 for gearboxes with a 35mm x 10teeth spline
