Carrillo DC7559H-1 Pro-H Connecting Rod with Cap Relief 7/16 WMC Bolt (Single)

The Carrillo DC7559H-1 is a single Pro-H connecting rod engineered for high-performance Cummins diesel engine builds. Featuring the Pro-H beam design with Cap Relief and a 7/16" WMC (H-11 tool steel) bolt, this rod is purpose-built for demanding applications where strength, precision, and reliability are non-negotiable.

Proprietary Carrilloy Steel Construction:

Each rod is machined from CP-Carrillo's proprietary Carrilloy steel — a chrome, nickel, moly, vanadium alloy that meets all VAR (Vacuum Arc Re-Melt) ASTM standards. The steel heat treat is validated by an independent metallurgist, and the mar-aged heat treatment process results in an Ultimate Tensile Strength (UTS) of 195,000 psi with a yield of 182,000 psi, while preserving low notch-sensitivity and ductility.

Key Features:

• Pro-H Beam Design — one of the stoutest beam configurations available for handling extreme engine loads
• Cap Relief — assists in oil evacuation for engines operating at higher loads and RPMs
• 7/16" WMC (H-11) Bolt — Ultimate Tensile Strength of 220,000 psi; rated for approximately 15–18 torque cycles
• Asymmetrical Threads — each thread is slightly different from the previous, providing evenly distributed thread engagement to enhance clamp load and extend fastener fatigue life
• Mahle Steel Bushing — included for added small-end durability
• Oversized Forging — manufactured from an oversized forging to ensure proper grain flow and eliminate surface inclusions
• Multi-Stage Quality Control — each rod is magnafluxed at least twice, Rockwell tested, and shot-peened before leaving the facility
• CNC Dimensional Validation — all critical CNC machines are equipped with probing to verify dimensional integrity
• Manufactured in the USA at CP-Carrillo's Southern California facility

Technical Specifications:

• Part Number: DC7559H-1
• Center-to-Center Length: 7.559 in. (192.00 mm)
• Style: Pro-H
• Bolt Size: 7/16"
• Bolt Type: WMC (H-11 Tool Steel)
• Pin End (PE) Width: 1.526 in. Tapered (38.76 mm)
• Big End (BE) Width: 1.526 in. (38.76 mm)
• Big End (BE) Bore: 2.8740 in.
• Sold as: Single rod

CP-Carrillo has been the industry's preeminent connecting rod manufacturer since 1963, trusted by professional race teams and serious diesel performance builders worldwide. The DC7559H-1 is the single-rod option for builders replacing or matching individual rods in their Cummins engine build.