Timing

The piston crown is concave and has four notches to prevent interference with the valve mushrooms.

The connecting rods are in hardened and tempered alloy steel, with a copper alloy bush for coupling with the piston gudgeon pin.

As the pins are floating on both the piston hubs and on the bush force-fitted in the connecting rod small end, their side stroke stop is made by two expanding circlips which are housed in special hollows machined on the actual hubs.

The right cylinder head pistons are positioned with the arrow stamped on the piston crown facing upwards and those of the left cylinder heads with the arrow pointing downwards.

TIMING

Direct drive by toothed belts, with overhead cams- hafts in case-hardened alloy steel.

The hydraulic tappets in contact with the cams operate the valves directly.

This device automatically eliminates "valve play" when the engine is running, thereby enormously reducing the need for periodic maintenance.

The exhaust valve stem is chromium-plated and inside it has a hollow filled 50 + 60% with sodium which improves dispersion of the heat to which they are subjected.

The valve seats are sintered in material suitable for use with unleaded petrol.

1. Cup
2. Oil circulation between inlet chambers
3. Oil inlet groove
4. Check valve
5. Piston
6. Cylinder
7. Pressure chamber
8. Valve stem

LUBRICATION

Lubrication is forced by gear pump. The oil pump is fitted on the rear engine cover and it is operated by a shaft that receives motion from a gear installed behind on the crankshaft. The oil withdrawn from the sump through a suction device is filtered by the mesh filter on the actual suction device and then sent under pressure by the pump through a groove to the oil filter with full-flow cartridge fitted with a safety by-pass valve which ensures that the oil can still pass if the filter is clogged.

The maximum lubricating pressure is adjusted by a special limiting valve fitted on the pump. After being filtered, the oil flows through a transversal duct into the main longitudinal delivery duct machined in the crankcase. From here, it is ducted through three grooves to the lubricating grooves of the crankshaft main and rod bearings.