Head Bolts / Torque To Yield Bolts

S.B. International, Inc.® offers Torque To Yield (TTY) Cylinder Head Bolts for Early and Late model Domestic and Import Automotive and Light Duty Truck applications. SBI® also offers some Cylinder Head Bolts for some Early Popular Domestic Automotive and Light Truck applications.  

Many current Import and Domestic engine designs use Torque To Yield (TTY) Cylinder Head Bolts, especially on engines with Aluminum Cylinder Heads in conjunction with Multi Layer Steel (MLS) Cylinder Head Gaskets. As the name implies, these bolts are designed to stretch a certain amount when tightened correctly and with that in mind, All SBI (TTY) Cylinder Head Bolts are designed and engineered to stretch within a controlled yield zone. Once this zone is reached, the (TTY) Cylinder Head Bolts by design will maintain a more precise and consistent level of clamping force across the entire Cylinder Head to Cylinder Block mating surface. The (TTY) bolts are stretched into their elastic range, and in many cases, the stretching approaches the Bolts' elastic limit, permanently stretching it. During the Heating and Cooling Cycle, these bolts will often take a permanent set and are not capable of regaining the correct clamping force "torque" if re-used. It is Recommended that on all engines requiring (TTY) Cylinder Head Bolts that the bolts are replaced every time the Cylinder Head is removed. SBI recommends referring to the OEM factory specifications for the correct tightening "torque" specifications for each engine.

  • NOTE: SBI sells (TTY) Cylinder Head Bolts in a single engine set for "L" (in-line) 4 and 6 cylinder engines because as they have only one Cylinder Head. In the case of the "V" style engines where in certain instances only one head may have been removed, we offer our Customers flexibility for a repair and sell many Cylinder Head Bolts in single head packs. This means that in most applications Two Sets will be required for a complete engine. Refer to the Notes column of the catalog application section where we will indicate how many sets are required for that engine.


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