Unquestionably the most important fasteners in any engine are the connecting rod bolts as they hold the key to the entire rotating assembly. A broken bolt will lead to catastrophic engine failure. As you can imagine the most critical joint is where the connecting rod halves mate. The rod bolts must support the primary tension loads caused by each rotation or cycle of the crankshaft. When the crank rotates the big end of the connecting rod essentially becomes oval-shaped and the rod bolts bend. As the crankshaft continues to rotate the rod becomes round again. With alternating tension loads and cyclic bending of the bolts it is very important to install fasteners that are able to exert a clamping force greater than the load imposed upon the joint tension. In addition to utilizing a rod bolt with sufficient strength to withstand the tremendous cyclical strains placed upon it it is absolutely imperative that the bolts be properly tightened. The preferred method of monitoring the correct amount of tension is through use of a stretch gauge. This is far more accurate than using a torque wrench. Moreover through subsequently checking the rod bolts length at teardowns it is possible to determine if it has been stressed beyond safe limits and must be replaced. For the most severe applications in conjunction with aftermarket I-beam rods ARP has developed the “ProSeries bolts. These ultra heavy-duty rod bolts are made from a special material designed ARP2000. It has approximately 200% the fatigue life of 8740 chrome moly steel and has a tensile strength of 220000 psi and is capable of more than 12000 lbs clamping force.

ARP 201-6102 – BMW E36-E46 Rod Bolt Kit
$57.43