For those who believe the 3FE engine doesn't get enough attention, here's something to change that perspective. On the 3FE motor, the front two head bolts also serve to mount the air pump. Unfortunately, these bolts are no longer available (NLA), and used ones are often in poor condition or very expensive.

These bolts are CNC machined and heat-treated from 17-4PH stainless steel. This high-quality alloy offers a balance of strength and durability. The yield strength of these bolts is 130,000 psi, with an elongation of 12% and a Rockwell C hardness of 33-39.

The elongation value is crucial for fasteners, especially in this application. A good, safe number for elongation is around 10%, which ensures that the bolt will yield (stretch) appropriately before reaching its ultimate tensile strength of 150,000 psi. This characteristic differentiates materials like ceramics, which fail almost immediately upon yielding.

To clarify, the yield strength marks the transition from elastic to plastic deformation. Below the yield point, the material returns to its original state after stress is removed. Beyond the yield point, the material undergoes permanent deformation, and at the ultimate tensile strength, it fails completely.

Specifications:

• Torque: 90 ft. lb.
• Sold individually (only two needed per engine)
• Made in the USA

Choose these superior head bolts to ensure the longevity and performance of your 3FE engine.

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