A diesel engine producing 3,200 lb-ft of torque will create an enormous amount of stress on the clutches and transmissions in an oil-burning dragster or puller, as Dan Scheid explains in the above video. But also think of what 130 pounds of boost and EGTs reaching 1,500 degrees are doing to the hardware on this Cummins-based engine.
Strength isn’t the only concern when spec’ing hardware for custom applications.
“We had a hard time accessing the intake bolts,” says Scheid, “and ARP came up with a fastener that worked perfect. We use ARP on just about everything.”
ARP’s diesel head stud kits are made from either ARP 2000, a proprietary alloy steel, that provides 220,000 psi tensile strength or Custom Age 625, a super alloy rated at 270,000 psi tensile strength. Each stud is thread rolled after being heat treated; and following heat treatment, each stud is centerless ground to assure concentricity.
ARP’s custom products are used throughout the racing industry, as noted in the additional video below. In fact, using ARP’s test equipment Kenny Duttweiler discovered that overusing head nuts can lead to a lower than expected clamp load. That revelation is important to machine shops that use the same head nuts over and over at the honing machine when they install a torque plate.
As all the engine builders note, working with ARP on a custom order is quite easy. Give them the dimensions and operating conditions and the ARP engineers will develop the correct fastener.