The Importance of Tightening the Head Bolt

When it comes to the many parts in an engine, none is more critical than the head bolts that hold the cylinder head tight against the block. The cylinder heads and block are subjected to tremendous loads during combustion that cause the fasteners to stretch and twist. When properly torqued, the bolts can form a strong seal to keep oil and steam from escaping between the blocks and heads.

In addition to stretching, head bolts must withstand torque (rotating force) and shear (twisting) forces to maintain their strength and clamping ability. It’s important to use accurate torque wrenches to tighten them in 3 to 5 incremental steps according to the recommended sequence and torque specs for your application. Doing this will ensure that each bolt is being evenly torqued and will help to reduce head distortion. If a bolt is not coming up to normal torque or has not retained a reading, it may be stretched and needs to be replaced.

Standard socket cap screws (SHC), low head socket caps (LHSC), and button head socket caps (BHCSC) are all tensile fasteners, meaning that they can resist bending and shear applications. These fasteners are used in a variety of applications including power and hand tools, automotive, machinery, metal stamping dies and plastic injection molds.

These fasteners are manufactured in a wide range of properties, materials, and finishes for different applications. Non-standard sizes, materials, threads and finishes are available for special orders. Portland Bolt can also create custom tooling to produce metric bolts with nonstandard head dimensions, imperial bolts with nonstandard head diameters and lengths, or hex heads with your company’s logo for a more professional look. button head bolt