Connecting Rod: Description and Operation

Connecting rod





The connecting rods are made of sinter-forged steel. The principle behind such is that a steel alloy in powder form is poured into a form. The form is pressed together and heated. The metal powder that is pressed together and heated to its fusing point fuses into a strong yet light connecting rod.

The greatly dimensioned small end has a bearing bushing of brass while the big end has two loose bearing shells. The top of the small end contains a bored hole for lubrication. Both bearing bushings and the bearing shells can be replaced.

The big end bearing cap is divided by splitting, which generates good fit and roundness.

Cam transmission
The engine is equipped with four overhead camshafts - two per cylinder head. A gear wheel mounted on the crankshaft drives the so-called primary chain, which is toothed. A self-adjusting hydraulic chain tensioner ensures that the primary chain has the correct tension. The chain is controlled with the help of three chain control guides.





The distribution chain drive the distribution pinion of the front and rear bank's timing chains. A timing chain runs from the distribution pinion up to the respective cylinder head. Each timing chain has two guides and a self-adjusting hydraulic tensioner.





The exhaust camshaft has a silent pinion while the intake camshaft has a hydraulic cam phasing mechanism (CVCP). The camshafts actuate rocker arms with roller bearings (aka roller finger followers) that are shaped like a ball cup at one end. This ball cup meets the ball-shaped upper part of the hydraulic valve clearance balancer. The other end of the rocker arm actuates the valve stem. The hydraulic valve clearance balancers keep the clearance between the rocker arm /roller bearing at zero. The valve clearance balancers thus do not participate in the movement of the valve mechanism.





The valves are steel with chromium-plated spindles. The exhaust valves are sodium cooled.