Crankshaft

Due to the special material with which they are made, these seals are polymerized when the engine is running and harden considerably during use, therefore it is no longer necessary to tighten the cylinder heads at the first service coupon.

CRANKSHAFT

This is forged in high-strength, hardened and tempered steel. It rests on three main bearings and its end float is adjusted by two half rings housed in the rear main bearing. Six counterweights accurately balance the rotating masses. A set of grooves run inside the shaft to lubricate the main and connecting rod journals.

MAIN AND CONNECTING ROD HALF BEARINGS

These are of the three-metal, thin shell type subdivided into two dimensional classes. The main half bearings have a hole and groove for lubricating the rod journals.

FLYWHEEL

This is in cast iron, with two ring gears in hardened and tempered steel: one for connection with the starter motor and one for the rpm sensor facing it. The "T" notch for checking engine timing is stamped on the flywheel.

PISTONS AND CONNECTING RODS

The pistons in aluminium silicium alloy are subdivided into five dimensional classes and they are available as Spares in three other oversize classes.

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 at 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 arc pointing downwards.

TIMING

Direct drive by toothed belts, with overhead cams shafts in case-hardened alloy steel. The hydraulic tappets in contact with the cams operate the valves directly. This device, which has also been adopted in the 1712 16V, 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.