ARP VW 1800cc Water-Cooled Connecting Rod Bolt Kit 104-6004

Because factory connecting rods (or aftermarket versions of OEM rods) are used in a variety of applications from rebuilt stock motors to modified powerplants used in circle track, marine and drag racing engines – including those with superchargers and/or nitrous oxide injection systems – 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
A premium grade 8740 alloy chrome moly steel is used to manufacture ARP High Performance connecting rod bolts. This material is heat-treated to provide a tensile strength in the 200,000 psi range, which is substantially stronger than the OEM bolts. Cycle testing shows ARP High Performance rod bolts to be nearly five times more reliable than stock bolts.

BETTER: WAVE-LOC HIGH PERFORMANCE BOLTS
The same heat-treated 8740 chrome moly steel is used to make these rod bolts as ARP’s standard High Performance rod bolts. The big difference is in the shank design, with ARP’s exclusive (and patented) Wave-Loc technology providing substantial benefits. Because there are fairly wide tolerances in factory bolt holes, the bolt must be able to fit snugly and a knurl is applied. Unfortunately, these knurls cut deep into the bolt material, leaving sharp edges and enormous “stress risers" that promote failure. That’s why ARP developed the Wave-Loc design that features symmetrical waves and provides an effective interference fit without creating stress risers in the bolt or the rod.

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 a special material designated ARP2000. It has approximately 200% the fatigue life of 8740 chrome moly steel and has a tensile strength of about 220,000 psi, and is capable of more than 12,000 lbs. clamping force.