CATERPILLAR 131-0421

The Caterpillar 131-0421 Fastener Group is a high-tensile, heavy-duty hardware bolt kit. It is specifically engineered to secure the cylinder head assembly down to the engine block deck, ensuring proper compression sealing and maintaining clamping torque under immense combustion chamber pressure.

1. Core Dimensions & Weight

Assembly Length: 310.00 mm (12.20 in)
Assembly Width: 55.00 mm (2.17 in)
Assembly Depth / Height: 55.00 mm (2.17 in)
Net Weight: 0.73 kg (1.60 lbs)

2. Material & Installation Torque Specs

Material Grade: Ultra-high-strength forged alloy steel optimized for high-clamping load applications.
Coating / Finish: Corrosion-resistant black oxide finish to prevent thread binding and degradation in oil-wetted high-heat spaces.
Thread Treatment Note: Prior to assembly, clean and lubricate all bolt threads with clean engine oil.
Primary Sealing Step 1 Torque: Tighten bolts to 30 ± 5 N·m (22 ± 4 lb-ft).
Primary Sealing Step 2 Torque: Advance tightening sequence to 100 ± 15 N·m (74 ± 11 lb-ft).
Primary Sealing Step 3 Torque: Increase torque load to 450 ± 15 N·m (330 ± 11 lb-ft).
Final Step Torque: Turn the fastener group to an additional sequence angle of 180 ± 5 degrees.
Post-Torque Step: Retighten auxiliary positions to 490 ± 15 N·m (360 ± 11 lb-ft).

3. Equipment & Engine Compatibility

This fastener group is an essential layout component designed to match the wide-bore Caterpillar 3500 engine architectures:

Diesel Engine Series: CAT 3508, 3508B, 3512, 3512B, 3512C, 3516, 3516B, and high-displacement 3524B mining power blocks.
Machine & Generator Groups: Extensively utilized in Caterpillar Engine-Machine systems, marine heavy propulsion rigs, and large-scale industrial generator sets.

4. Part Cross-References & Kinship

Component Assembly Mix: Includes 7N-1961 heavy-duty cylinder head bolts.
Direct System Twin: Often paired on the same engine block architecture alongside the 131-0420 Cylinder Head Fastener Group.
Alternative Part Numbers: 1310421, 131-0421.