Product Description
Protect your Cummins bottom end under big power. INDUSTRIAL INJECTION’s HX Series coated race main bearings add ~.001" extra oil clearance (STD +.001) and a dry-film lubricant coating designed for competition abuse and cold-start protection. Built on the proven Clevite H/HX performance bearing architecture with high crush, medium eccentricity, and enlarged chamfers for crank fillet clearance. Sold as a complete main set.
Fitment
- 1989–1998 5.9L 12-valve Cummins (6BT)
- 1998.5–2002 5.9L 24-valve Cummins (ISB)
- 2003–2007 5.9L common-rail Cummins
- 2007.5–2018 6.7L common-rail Cummins
What’s Included
- Complete main bearing set (STD +.001, coated) for 1989–2018 5.9L/6.7L Cummins
Why These Bearings
- HX series extra clearance (~.001") helps maintain oil film at high load/RPM
- Dry-film coating reduces scuffing during cold starts and oil-starved events
- Performance geometry: high crush, medium eccentricity, enlarged chamfers
- Race-proven H/HX base engineered for competition engines
Recommended Parts (CPP internal links)
- ARP 247-5402 Main Stud Kit (1989–1997 12V)
- ARP 247-5401 Main Stud Kit (1997.5–2018 without factory girdle)
- Industrial Injection HX Series Coated Rod Bearings (’89–’02)
- MAHLE MS-2328H H-Series Main Bearings (STD) — Alternative
- Shop All Cummins Main Bearings
Helpful Notes
- Line-hone and measure the block and crank; set clearances per your build and oil viscosity.
- Pair with appropriate main studs and check fillet/chamfer clearance on performance cranks.
Cross-Reference / Alternatives
- Industrial Injection PDM-MS-2328HC (H Series, coated)
- MAHLE / Clevite MS-2328H (STD)
- MAHLE / Clevite MS-2328H-.25MM (-.010")
- Cummins 4955853 OEM Main Bearing Set (STD)
FAQ
What’s the difference between H and HX?HX adds approximately .001" extra oil clearance (STD +.001) versus H. HX is often chosen for higher load/RPM builds where more oil film is desirable.
Do these bearings include a thrust position?They are sold as a complete main set; verify thrust configuration during mock-up and measure endplay to spec.
Are coated mains worth it?The dry-film coating helps during cold starts and transient oil-starved events, reducing scuffing and extending bearing/journal life in competition use.
Should I line-hone the mains?Yes—any performance rebuild should confirm housing bore, alignment, and crush. Line-hone as needed and set target clearances based on oil viscosity and use case.
