If your engine is an early LS1 (2003 and earlier), you will need unequal length head bolts which have their own torque sequence. You can find instructions for them here.
Installing head bolts correctly is essential to prevent leaks and a loss of compression from blowing a head gasket.
Stock head bolts are torque to yield which means they stretch after installing them, this means they CANNOT be reused.
Note: If you are using aftermarket head bolts or head studs, you must following the instructions that come with them.
Tools Required:
- M11 x 2.00 Thread Chaser (such as ARP 912-0011)
- M8 x 1.25 Thread Chaser (such as ARP 912-0001)
- Torque Wrench (M11 & M8 sockets)
- Torque Angle Gauge (or a Torque Wrench that can perform this function)
Parts Required:
Pre-Installation Checks:
- All head bolt threads are clean and undamaged
- Dowel Pins are in the engine block (two on each side)
- Block deck surface is clean (mating surface between block and head)
- Block is secured (if the engine moves while performing the angle torque steps, it will mess up your readings)
Installation Procedure:
- Place head gaskets onto the block.
- Set the cylinder heads onto the head gaskets, ensuring it sits onto the dowels properly.
- Install all head bolts finger tight.
- Torque all the M10 heads bolts in 3 stages in the sequence bellow (1 through to 10):
- 22 ft lb / 30 nm
- 90 degrees
- 70 degrees
- Torque all the M8 bolts to 22 ft lbs / 30 nm in the sequence below (11 through to 15).
- Repeat these steps for the other head.
NOTE: All torque specifications come from official GM / Holden documentation.