Connecting rods

Robust force transmission

The high strain on the connecting rod due to tension, pressure and torsional forces requires connecting rod designs with high strength and low weight. With the high-quality product range from Motorservice, you are always on the safe side.


Connecting rods

Connecting rods connect the crankshaft to the pistons, thus conveying the gas and inertial forces to the crankpins of the crankshaft.

Connecting rods are forged from steel, with either alloyed steel or quenched and tempered steel used depending on the strain.


Milled or ground separation planes

A proven method of creating the connecting rod bearing cap is separating or sawing. The large connecting rod eye is sawed apart and the separation planes are then milled and, if necessary, ground. 

On flat separation planes, the connecting rod bearing cap is fixed in place using locating bolts or register pins. Due to their toothing, toothed separation planes do not need additional means of fixation.


Straight and angled separation

On very large crankpins, the connecting rods can have angled separation. The angled position is required to push the connecting rod through the cylinder bore despite the large connecting rod eye. If connecting rods have angled separation, it is crucial that the installation position is correct, particularly with in-line engines.

Cracked separation planes

Cracked connecting rods are initially produced as a single unit, then given break lines (sinter rods) or laser notches (steel connecting rods) and split (cracked) into two parts. Both parts are screwed together when the connecting rods are assembled. Due to the point of fracture, they fit together precisely. 

Cracked connecting rods are advantageous with regard to strength, costs and production accuracy. Connecting rods and connecting rod caps sit precisely on one another, which allows for optimal force transmission.

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Parallel connecting rod
Trapezoidal connecting rod
Stepped connecting rod

Parallel and trapezoidal connecting rods

The steadily increasing combustion pressures cause everincreasing stresses in the piston pin mounting of the connecting rods. Trapezoidal and stepped connecting rods are increasingly being used, in order to reduce the moving masses and better absorb the forces by optimising the size of the usable area.

Further information

1 Small connecting rod eye
2 Conrod bush (omitted in the illustration)
3 Oil bore
4 Housing bore
5 Bearing cap
6 Connecting rod bolt
7 Large connecting rod eye