2024 ARP Catalog

44 WARNING: Cancer and Reproductive Harm - www P65Warnings ca gov s l California Residents WARNING: Cancer www P65Warnings ca gov TECH NOTE: ROD BOLTS 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 tear-downs, it is possible to determine if it has been stressed beyond safe limits and must be replaced. OEM Replacement Rod Bolts CHOOSE FROM THREE ARP OEM REPLACEMENT ROD BOLTS: OEM connecting rods are used in a variety of applications from rebuilt stock motors to modified powerplants used in circle track, marine and drag racing engines. ARP offers replacement rod bolts in three different models. All of them are substantially better than the stock OEM and most aftermarket bolts. GOOD: STANDARD HIGH PERFORMANCE BOLTS Premium grade 8740 alloy chrome moly steel is used to manufacture ARP High Performance connecting rod bolts. These bolts provide a tensile strength in the 200,000 psi range and fatigue strength nearly five times greater than stock rod bolts. BETTER: WAVE-LOC® HIGH PERFORMANCE BOLTS ARP developed the Wave-Loc shank design that features symmetrical waves with an effective interference range of of 0.001˝ to 0.005˝ for proper cap alignment. The waves replace the knurl on standard replacement bolts – eliminating the stress risers that are created when cutting into the shank - which create potential failure points. The tensile and fatigue strengths are the same as our regular high performance rod bolts. BEST: “PRO” SERIES WAVE-LOC BOLTS For the most severe applications, in conjunction with aftermarket I-beam rods, ARP has developed the “Pro” Series Wave-Loc bolts. These ultra heavy-duty rod bolts are made from high strength ARP2000. This material doubles the fatigue life of 8740 chrome moly steel and has a tensile strength of 220,000 psi, which means it can delive more than 12,000 lbs. of clamping force. ROD BOLTS