PISTONS AND CONNECTING RODS-F.3 A----+--O F6 Fitting the Piston Rings Fit piston rings to the piston. Rings vary according to engine type and application as follows: reading from the top of the piston. 4.108 Engines Standard Pistons : 1. 12. I 1 3 . 14. 15. I , I Plain parallel faced compression Internally stepped compression Internally stepped compression Laminated segment oil control' Slotted scraper Engines rated at 3,000 rev/min and below have a slotted scraper fitted in the fourth groove which has the same width, clearance and gap as the fifth piston ring. : These have either four or three rings per piston as I follows: ; Controlled Expansion Pistons : 1.
Chrome insert parallel faced I 2. Internally stepped I 3. Internally stepped F8 : 4. Spring loaded scraper I 1. Chrome taper faced I 2. Internally stepped taper faced : 3. Spring loaded scraper 4.99 Vehicle Engines 1. Chrome parallel faced compression. 2. Internally stepped compression. 3. Internally stepped compression. 4. Slotted scraper. 5. Slotted scraper. 4.107 and 4.99 Agricultural and Industrial Engines 1. Plain parallel faced compression. 2. Internally stepped compression. * 3. Internally stepped compression. * 4. Chrome spring loaded scraper. 5. Slotted scraper. *4.99 agricultural engines have taper faced cast iron compression rings fitted in the 2nd and 3rd ring grooves.
After an appropriate period of service, when indica- tions of piston ring and/or cylinder bore wear may be- come apparent, a replacement ring pack has been made available for fitting exclusively to 4.99 service engines and includes a taper faced ring for fitting in the top ring groove. F7 NOTE: All the rings quoted above except the laminated and spring loaded type may be fitted by means of an