| PISTON | |||
| Type Slotted | |||
| Material | Aluminium alloy tin plated | ||
| Form | Taper and oval turned | ||
| No. of rings-Compression | Two | ||
| Scraper | One | ||
| Compression-Height | 1.850 in. /1.845 in. | (48.99/46.86 mm.) | |
| Identification (mark on crown) | High | M84 or R92 | or HC |
| Low | M78 or R84 | or LC | |
| Piston length | 3.25 in. | (85.57 mm.) | |
| Max. permissible weight variation between any two pistons in a set... | 2 Drams | (3.55 grms.) | |
| Grade | |||
| SERIES I ALPINE, SERIES III RAPIER | SERIES II, III ALPINE, SERIES III A, IV RAPIER | SERIES IV ALPINE | |
| A. 3.1088 /3.1092 in. (78.963/78.974 mm.) | A. 3.2088 /3.2092 in. (81.503/81.514 mm,) | A. 3.2092/3.2096 in. (81.514/81.524 mm.) | |
| B. 3.1092 /3.1096 in. (78.974/78.984 mm.) | B. 3.2092/3.2096 in. (81.514/81.524 mm.) | B. 3.2096/3.2100 in. (81.524/81.534 mm.) | |
| C. 3.1096/3.1100 in. (78.984/78.994 mm.) | C. 3.2096/3.2100 in. (81.524/81.534 mm.) | C. 3.2100/3.2104 in. (81.534/81.544 mm.) | |
| D. 3.1100/3.1104 in. (78.994/79.004 mm.) | D. 3.2100 /3.2104 in. (81.534/81.544 mm.) | D. 3.2104/3.2108 in. (81.544/81.554 mm.) | |
| E. 3.1104/3.1108 in. (79.004/79.014 mm.) | E. 3.2104/3.2108 in. (81.544/81.554 mm.) | E. 3.2108/3.2112 in. (81.554/81.564 mm.) | |
| (For Service use) | (For Service use) | (For Service use) | |
| F. 3.1108/3.1112 in. (79.014/79.024 mm.) | |||
|
(For Service use) |
|||
| Ring clearance (between ring and groove) | .0015 in. /.0035 in. | (.038/.088 mm.) | |
| Ring gap-Top ring | (Series I Alpine, Series III Rapier) | .012 in. /.020 in. | (.30/.5l mm.) |
| (Series II, III, IV Alpine, Series IIIA, IV Rapier) | .024 in. /.032 in. | (.1/.816 mm.) | |
| Second and third ring | 009 in. /.014 in. | (.23/.36 mm.) | |
| LUBRICATION SYSTEM | |||
| Type of pump | Eccentric lobe type | ||
| Types of intake | Gauze filter on pump | ||
| Pump drive | Skew gear on camshaft | ||
| Normal pressure | 55 lbs. sq. in. | (3.8 kg. /cm.²) | |
| (Hot) at 50 m.p.h. | (80 k.p.h.) | ||
| Filter-Make | Fram or Tecalemit | ||
| Type | Full flow | ||
| Maker's element No | Framn FC.41721. | Tecalemit FP.3305/101 | |
| Model | Fram FF.42378. | Tecalemit PSK. 1663 | |
| Filter (cars with Solex carburettor) | Full-flow throw away type | ||
| FUEL PUMP | ||
| Make and type | A.C. No. E/FP.1880B mechanical | |
| Operation | Lever by eccentric on camshaft | |
| Pressure | 1.5 – 2.5 Ibs. /sq. in. | (0.11-0.18 kg./ cm²) |