97 visit www.apracing.com for installation drawings & up to date product range details CLUTCH FUNCTIONALITY / TERMINOLOGY - CLAMP LOAD:- Force applied by the diaphragm spring, on driven plates via main and intermediate pressure plates. Clamp load will vary depending on the diaphragm spring and pressure plate ratio used. - RELEASE LOAD:- Force required on the diaphragm spring fingers to disengage the clutch. - PRESSURE PLATES:- The main pressure plate provides the fulcrum point at which clamp load is transmitted, through its own friction face into the clutch. The pressure plates positioned between drive plates, are known as intermediate pressure plates. - PUSH TYPE:- The conventional, and most popular type of diaphragm spring clutch, where the release bearing is pushed against the diaphragm spring fingers, (i.e. towards the flywheel), to release the clutch. - PULL TYPE:- This type of clutch, has the release bearing fulcrum inside the clutch, and requires the diaphragm spring fingers to be pulled, (i.e. away from the flywheel), in order to release the clutch. Although generally more complex, in terms of release mechanism, pull types, are more efficient in terms of clamp and release loads. - DIAPHRAGM SPRING:- Belleville (or disc) spring with a series of integral release fingers on the inside diameter. TECHNICAL SPECIFICATIONS - TORQUE CAPACITY:- The torque capacity of the clutch is dependent upon the clutch diameter, the number and type of driven plates used, the load rating of the diaphragm spring and the pressure plate ratio (normally predetermined by AP Racing during the design process). The table below gives the recommended maximum engine torque capacity for all the avail- able combinations of these factors for both conventional push type clutches and pull type clutches. The number of driven plates used in the clutch will to a large extent be determined by the torque capacity the clutch will be required to accommodate, but operational requirements must be taken into consideration. Increasing the number of driven plates decreases the wear rate and hence the interval before the driven plates will require replacing, but will also increase the overall height, weight and the moment of inertia of the clutch package. Clutch Type . Diaphragm Spring Load Rating Nm (lbft) D = GLD (Gold) S = SLV (Silver) T = TGY (Triple Grey) C = CRV (Double Grey) O = ORA (Orange) N = GRN (Green) G GRY (Grey) C O N V E N T I O N A L P U S H S I N T E R E D Ø115mm 3 Plate 878 (647) 664 (490) 499 (368) Ø115mm 4 Plate 1014 (747) 882 (651) 676 (498) 588 (434) Ø140mm Single Plate 210 (155) 157 (116) Ø140mm 2 Plate 420 (310) 314 (232) Ø140mm 3 Plate 630 (465) 471 (348) Ø140mm 3 Plate ‘I’ Drive 870 (641) Ø140mm 4 Plate 840 (620) 628 (464) Ø184mm Single Plate A-Ring 424 (313) 266 (196) 164 (121) Ø184mm Single Plate 424 (313) 266 (196) 164 (121) Ø184mm 2 Plate A-Ring 848 (625) 532 (392) 327 (241) Ø184mm 2 Plate 848 (625) 532 (392) 327 (241) Ø140mm 2 Plate ‘I’ Drive 636 (469) Ø184mm 3 Plate A-Ring 978 (721) 631 (465) 394 (291) Ø184mm 3 Plate 1272 (938) 798 (588) 491 (362) C E R A M E T A L L I C Ø140mm 2 Plate 398 (294 298 (220) Ø184mm Single Plate 413 (305) 259 (191) 160 (118) Ø184mm 2 Plate A-Ring 636 (469) 421 (310) 263 (194) Ø184mm 2 Plate 636 (469) 421 (310) 263 (194) Ø184mm 2 Plate ‘I’ Drive 636 (469) 636 (469) Ø184mm 2 Plate ‘I’ Drive, Cushion Cover 1016 (748) 785 (579) 711 (524) Ø184mm - 2 Plate Lug Drive, Cushion Cover 782 (576) 708 (522) Ø184mm 3 Plate 1257 (926) 789 (581) 485 (358) Ø200mm Single Plate 343 (253) 301 (222) Ø215mm Single Plate 580 (427) 425 (314) Ø215mm 2 Plate 842 (621) 564 (416) Pull Ø140mm 4 Plate ‘I’ Drive 1410 (1039) 1392 (1026) MAINTENANCE Regular inspection and maintenance is essential, to maintain optimum clutch performance. Excessive heat generation (often witnessed by discol- ouration of steel pressure plates), due to prolonged, or repeated slip can result in loss of diaphragm spring load, as well as driven plate damage. In such cases the clutch should be replaced or reconditioned. Pressure plate working faces, should be checked for flatness using a straight edge and feeler gauge. ‘Out of flat’, pressure plates or driven plates can result in difficulties releasing the clutch, and consequently drag. Pressure plates should be replaced when worn, or more than 0.10mm (0.004”) out of flat. Replace driven plates, if there are signs of damage or when thickness has been reduced to the figures given in the technical information for each individual clutch. PART NUMBERS A new part numbering system has been introduced on some of the clutch series in this catalogue. The table below provides a brief explanation of the make up of the part numbers. CP7372 - O E 90 - SF Clutch series No. Diaphragm Spring Ratio Driven Plate Type Flywheel Type D = (Gold) E = EHR (Extra High Ratio) 80 = Cerametallic Style Assemblies 7.11mm Thick SF = Stepped Flywheel S = (Silver) T = TGY (Triple Grey) C = CRV (Double grey) O = ORA (Orange) H = HiR (High Ratio) 90 = Sintered Style Assemblies 2.63mm Thick FF = Flat Flywheel N = GRN (Green) G = GRY (Grey) ORDERING When ordering anAP Racing Clutch please quote the correct part number for the assembly required wherever possible. The driven plate(s) must be ordered separately under their own part number. The types of driven plate design, suitable for that particular race clutch assembly, are detailed on pages 98 to 113. However, not all popular spline variations are listed in these sections, please refer to page 116, where a more comprehensive list of driven plate spline sizes can be found. If the spline size you require does not appear in this list, please contact AP Racing for information. ‘ A’ appears only when an Aluminium Alloy cover is required For a Steel cover no letter is required e.g. CP2125CRV The Clutch Family Part No. Diaphragm Spring Rating CP2125 A CRV Examples & Explanation of Part Numbers:- METALLIC RACE CLUTCH - General Information SINTERED OR CERAMETALLIC CONT’D?. - ‘A’ RING TYPE:- The ‘A’ Ring clutch type is only available, in Ø184mm diameter. Push types are available, with either a steel or aluminium alloy cover, (functionally there is no difference between the steel and aluminium alloy cover), however, the aluminium alloy cover assembly, gives a weight saving of approximately, 300g over the steel version and has lower inertia. - NUMBER OF DRIVEN PLATES:- The number of plates required for an application, will depend on engine torque, clutch diameter, and clamp load. Generally, a smaller diameter clutch will require more plates than a larger diameter unit. A comprehensive range of splines, is available to suit most transmission input shafts. Details on page 116. If the spline required is not in this table please contact AP Racing technical department.