What is the torque sequence for head bolts?
Torque sequence refers ro the pattern in which you tighten the bolts. The overall goal is to spread the torque evenly as you are tightening the bolts. Usually, you start at one bolt, and you work your way around in a circular pattern. Doing so ensures that your head won’t be warped during the tightening sequence.
What is the torque sequence?
Bolt tightening sequence, or torque sequence, is defined in the torque tightening procedure. Flange joints are torqued tight with the help of a torque wrench (manual or hydraulic). The clamp load produced during tightening is higher than 75% of the fastener’s proof load.
What order should you tighten cylinder head bolts in?
Normally you would tighten conventional head bolts in a crisscross pattern in three steps, to one-third, two-thirds, and then to the final torque. Stretch bolts are tightened in a torque-plus-angle sequence. Various engines use similar but different sequences and specification.
Why is torque sequence important?
A good tightening sequence ensures that an even preload distribution is achieved in the joint (See Dia. A). Since joints containing conventional gaskets have a comparatively low compressive stiffness, bolt preloads in such joints are particularly sensitive to the tightening sequence.
How do you torque a 350 head?
The tightening of Chevy 350 cylinder head bolts must always be done in a helical sequence, starting from the center bolt and working outwards in a clockwise spiral. It’s best to first tighten all the bolts to 25 foot-pounds, then 45 foot-pounds and finally 65 foot-pounds to maintain uniform pressure across the head.
Why is a torque sequence important?
Because the joint surfaces compress, tightening one bolt in the vicinity of another will affect the preload generated by the first bolt tightened. A good tightening sequence ensures that an even preload distribution is achieved in the joint (See Dia. A).
What is the purpose of a torque sequence?
With such a sequence, each bolt is tightened more than once so as to reduce the preload reduction caused by the tightening of the other bolts in the joint.
What is a torque specification?
When attaching a wheel to a vehicle, torque specifications are the amount of force recommended on the hardware to ensure proper installation. It can damage the wheel, strip the bolts and even cause the brake rotors to warp. Too much torque also can damage brake rotors.
What is the head bolt torque specs?
Torque specs: Torque specs: CYLINDER HEAD BOLT TORQUE SPECS (tightening) / (loosening) 8, 4, 2, 6, 10 7, 3, 1, 5, 9. Torque in steps: 22ft-lbs (264in-lbs), Then to 63ft-lbs (756in-lbs) (final spec) 94+ Teg
What is head bolt torque spec?
Torque, as a specification for head bolts, refers to the amount of rotational force required to tighten the bolts properly . Torque is measured in foot-pounds. Manufacturers provide torque specifications to guide mechanics in properly tightening the bolts connecting the cylinder heads to the main engine.
What are cylinder head torque specs?
Cylinder head bolt torque is 35 Nm or 26ft lbs plus 180 degrees. See picture for sequence. All bolts must be torqued to 35 prior to additional degrees.
What are the torque settings for head bolts?
SOURCE: head bolts torque settings According to my haynes manual for G-S reg, 1989-1998 it goes as follows, Stage 1:- Tighten all bolts by hand until bolt heads just contact cyl. head. Stage 2:-Tighten all bolts to 40Nm or 30lb ft. Stage 3:-Angle tighten all bolts a further 60 degrees. Stage 4:-Angle tighten all bolts again a further 60 degrees.