How do you calculate cylinder head bolt torque?
Each cylinder head bolt creates only one part of the total amount of clamping force necessary to seal the cylinder heads to the engine block. To determine how much torque is needed for each bolt it is necessary to divide the number of bolts by the total amount of cylinder pressure the engine produces.
Why is there a tightening sequence for the cylinder head bolts?
Tightening a bolt stretches it, while pulling the head and block together. These bolts elastically deform and return to their original dimensions when loosened. Friction between the bolt head, its washer, and the cylinder head isn’t consistent. Stretch bolts are tightened in a torque-plus-angle sequence.
What is the tightening sequence of cylinder head?
Start 1 2 4 3 8 7 5 6 9 10 Cylinder 1 Cylinder 2 Cylinder 3 Cylinder 4 The bolts are tightened in several steps, for instance: • 1st step 20 Nm (i.e. tighten bolts 1 – 10 with tightening torque of 20 Nm) • 2nd step 60 Nm (i.e. tighten bolts 1 – 10 with tightening torque of 60 Nm) • 3rd step 90° (i.e. tighten bolts 1 – …
What happens if you over tighten a cylinder head?
When you overtorque above 15% of recommended which in this case would be about 95 ft/lbs you basically turn the fastener into a rubber band. Add heat and pressure and head gasket blows and the head can even warp. …
Why are torque specs important for head gasket?
Manufacturers provide torque specifications to guide mechanics in properly tightening the bolts connecting the cylinder heads to the main engine. Improper tightening of the bolts on a cylinder head results in uneven distribution of tension across both the bolts and the head gasket.
What causes proper torque in a cylinder head?
II fImportance of Proper Torque When a head gasket is installed between the cylinder head and engine block, tightening the head bolts compresses the gasket slightly, allowing the soft facing material on the gasket to conform to the small irregularities on the head and block deck surfaces.
How much torque do you need for a 10 bolt cylinder head?
Many cylinder heads require multiple torque sequences to achieve proper tension. For example, a 10-bolt cylinder head may require you to tighten them all first to 42 foot-pounds in a specified order, then to 75 foot-pounds in the same order.
Where can I find the latest torque specs?
Find the most up-to-date torque spec listings in electronic format. FelPro-Only.com is your convenient source for advanced sealing information. It’s the place to learn and share “tricks of the trade,” find proper diagnosis and installation instructions, and enjoy easy access to parts reference.