The ISX also has horizontal cross-bolts on the main caps (two per cap). Do not forget these.
You will see different specs online for "used" bearings vs. "new" bearings. Why?
If you are installing NEW bearings, you MUST use NEW bolts, and you MUST use the full angle spec. Do not listen to old-timers who say "just ugga-dugga it." The ISX is a precision engine; 5 degrees off on a rod bolt can reduce clamping force by 30%.
If the blind hole in the block for the main bolt has oil or water in it, you can hydraulically crack the block. Clean the holes with compressed air and a bottoming tap before installing new bolts. cummins isx main and rod bearings torque specs new
If you are rebuilding a Cummins ISX (Industrial Series eXperimental) engine—whether it’s the popular ISX15, ISX12, or the earlier EGR models—getting the torque specs for the main and rod bearings wrong is a guaranteed path to catastrophic failure. The ISX is a high-horsepower, high-torque workhorse found in Peterbilts, Kenworths, Freightliners, and Volvo trucks. Its composite block and complex joint designs require precision.
This article provides certified torque specifications for new main and rod bearings on a Cummins ISX. We will cover bolt tightening sequences, angle torquing (torque-to-yield), and critical steps that many online guides miss.
Disclaimer: This data is for informational purposes based on Cummins OEM guidelines. Always verify with your engine’s specific service manual (Cummins Quickserve). Torque specs may vary between ISX CM870, CM871, CM2250, and CM2350 models. The ISX also has horizontal cross-bolts on the
The phrase "Cummins ISX main and rod bearings torque specs new" is general. Here are model deviations:
Note on Girdles: The ISX uses a structural oil pan and a bedplate. The "main bearing torque" applies to the 10 bolts holding the lower cap to the cylinder block.
Before discussing torque numbers, it is vital to understand that Cummins transitioned the ISX platform from standard torque-to-yield (TTY) bolts to a newer design in later models (roughly post-2010 emissions engines). You will see different specs online for "used" bearings vs
Rule of Thumb: If you are unsure which bolt you have, look at the head of the bolt and consult the parts book for your Engine Serial Number (ESN). Never reuse Torque-to-Yield bolts. If you remove them, they must be discarded and replaced.
If you are looking at the crankshaft from the front (fan side):
Tighten vertical bolts working outward in a spiral.