When a piston is near Top Dead Center (TDC) on the combustion stroke, peak cylinder pressure is somewhere in the range of 1,000 psi for production engines at full power. Race engines peak cylinder pressures are generally 1,500 or more psi. This is somewhere near 14,000 pounds of pressure against the cylinder head at full throttle!
Think about the cylinder head bolts that have to keep the cylinder head attached to the block. In this case, these bolts must handle more than 5 tons per bolt at wide-open throttle. Now imagine what kind of pre-load these bolts must have to operate properly – and how to achieve that pre-load.
ARP has become respected for their bolt technology, due in large part to engine builders’ confidence in the company’s connecting rod bolts and cylinder head bolts and studs over many years.
Not Limited To Head Bolts
The crew at ARP wants enthusiasts to know that the ARP bolt technology extends past connecting rod and cylinder head bolts. “They have a fastener product for almost any bolt, stud, washer, or nut you can find on an automobile,” says racing enthusiast Bill Holland. “ARP fasteners should not be limited to engine applications either,” he added, “anywhere in the entire drivetrain could benefit from ARP fasteners.”
Modern engines and drivelines are designed to be stronger than ever before, and many of these are built to handle extreme loads right from the factory. Any work or upgrades to these components requires a great deal of attention during installation. Specifically, the installation pre-loads of bolts or studs (the amount the fastener is stretched during installation) is critical.
ARP’s Ultra-Torque Assembly Lube in Action
It is very rare that any bolt or stud is installed dry. Most builders will use engine oil, sealant, thread locker, anti-seize, or some other material to help lubricate the threads. Over the course of many years, engine and driveline mechanics have debated what assembly lube to use.
For builders using ARP products, the company has been very clear in its written policy: “ARP provides torque specs for our fasteners based on using ARP Ultra-Torque. If you’re not using our specs and our lube, you have no real idea what pre-load you’re getting.”
Company spokesmen have assured us they have done testing to measure the torque applied and the resulting pre-loads. They have tested against most other assembly lubes that builders use and claim to have the results that support ARP’s Ultra-Torque and Assembly Lube maintains pre-loads better than anything else.
For more information on the Ultra-Torque Assembly Lubrication or other fine products from ARP, visit them online at arp-bolts.com.