Why You Should be Checking Connecting Rod Bolt Stretch | Diesel Engine Assembly

Our recent expansion into the performance diesel world was by no means a copy and paste of our design onto an OEM base. After engineering research and FEA was complete and we had test parts in our hands, we went hands-on and built dyno engines for our friends S&S Diesel to put to the test for us. One of those was the ever-popular Cummins 6BT (5.9L).

Assembling a diesel engine in preparation of making upwards of 2,000 lb. ft. of torque requires precision and uninterrupted attention to detail. Among these critical details are bolt stretch values. BoostLine diesel connecting rods are equipped with ARP 2000 12mm fasteners, providing 20% more clamping force over bolts traditionally found in diesel rods which helps prevent rod cap stretch while also aiding in ease of engine assembly.

Check out our Complete Guide on Properly Torquing with Bolt Stretch Below

Clamping force sounds great at face value, but it is critical to confirm you’re achieving that ideal clamping force when assembling your engine by checking bolt stretch values. The amount of bolt stretch for proper clamping force with these Cummins rods is .0065″ – .0070″. In this video, we walk you through the process of confirming bolt stretch step-by-step, as well as cover several other key factors in proper diesel engine assembly. If you want to see more details on the industry’s strongest diesel connecting rods, click the button below.