To properly install your LS Cylinder Heads, follow the steps below. This will prevent oil and coolant leaks and a loss of compression from a blown head gasket.
**If you use aftermarket bolts or studs, follow the instructions that came with your new fasteners.**
Pre-Installation
Before installing your heads, ensure the following:
- The bolt holes in the block are clean and the threads are not damaged.
- The valves, seals, and springs are properly installed.
- The freeze plugs are installed.
- The coolant temperature sensor is installed in the driver’s side head.
- The coolant passage plug is installed on the passenger’s side head.
- The block is secured to the engine stand.
- It may rotate with the added weight of the cylinder head.
Installation Process
- Press new Dowel Pins into the engine block.
- There are 2 dowels per side (in holes #7 and #8).
- They align the head to the block. Always replace them before installing your cylinder heads.
- If needed, lightly tap them in with a hammer.
- Clean the deck surface of the block with a clean rag and acetone (or a similar cleaner).
- Place the Head Gasket on the block.
- Make sure “front” or “this side up” is facing the appropriate direction.
- Clean the deck surface of the head with a clean rag and acetone (or a similar cleaner).
- Gently set the cylinder head on top of the head gasket.
- Be sure it sits properly on the dowels.
- Take care not to nick or scratch the deck surface of the head.
- Install all the bolts finger-tight.
- Torque the M11 bolts (#1-10) in 3 passes.
- See below for torque specs and sequence.
- Use a quality Torque Wrench and Torque Angle Gauge.
- Torque the M8 bolts (#11-15) in 1 pass.
- See below for torque specs and sequence.
- Repeat this process for the other cylinder head.
LS Cylinder Head Torque Specs | ||||
Engine Family | Bolt Size | First Pass | Second Pass | Final Pass |
Gen. 3 (LS1, LS6, etc.) | M11 x 155.5mm | 22 ft.-lbs. | 90 degrees | 90 degrees |
M11 x 101mm | 50 degrees | |||
M8 x 46mm | - | - | 22 ft.-lbs. | |
Gen. 4 (LS2, LS3, etc.) | M11 x 155.5mm | 22 ft.-lbs. | 90 degrees | 70 degrees |
M8 x 46mm | - | - | 22 ft.-lbs. |
Notes
- Stock-style cylinder head bolts are Torque to Yield Fasteners.
- NEVER reuse old TTY bolts.
- 2003 and earlier blocks use 155.5mm long bolts in holes #1-8 and 101mm long bolts in holes #9-10.
- The final torque angle is different. Make sure you use the right specs!
- For engines that use M12 head bolts, like the LSA and LS9, refer to your GM service manual.