ARP started applying technology to race fastener design and manufacturing in 1968. We'll discuss five components of fastener technology in detail.
Today's critical diesel fasteners - head studs and bolts, main studs and bolts, and driveline - have been designed stronger than ever before to handle the extreme loads. As a results, installation pre-loads - the amount the fastener is stretched during installation - are very high.
There are three methods that can be employed to determine how much tension is exerted on a fastener; using a torque wrench, measuring the amount of stretch, and turning the fastener a pre-determined amount (torque angle). Of these methods, use of a stretch gauge is the most accurate.
The following material is intended to provide a brief overview of the metallurgical considerations that influence the design and production of the most reliable fasteners in motorsports. It is hoped that a simple understanding of the knowledge and commitment required to produce this reliability will make your future fastener decisions much, much easier.