53. Cylinder Head Cleaning and Inspection

Cylinder Head Cleaning and Inspection (LS3, LS9)

Special Tools
* J 8089 - Carbon Removal Brush
* J 9666 - Valve Spring Tester
For equivalent regional tools, refer to Special Tools (Special Tools)




Warning: Refer to Safety Glasses Warning (Safety Glasses Warning).


Note:
* When cleaning a cylinder head in a thermal type oven, do not exceed 204°C (400°F).
* Be careful not to scuff the chamber.

1. Clean the following components:

* Use the J 8089 - Brush in order to remove the carbon from the combustion chambers.
* Gasket surfaces
Refer to Replacing Engine Gaskets (Replacing Engine Gaskets).
* Valve stems and heads on a buffing wheel
* Bolt hole threads
Remove all dirt, debris, or threadlocking material from the bolt holes.

2. Inspect the cylinder head for the following conditions:

1. Cracks in the exhaust ports and combustion chambers
2. External cracks in the water chambers
3. Gasket surfaces for excessive scratches or gouging
Refer to Replacing Engine Gaskets (Replacing Engine Gaskets).
4. Bolt hole threads for debris or damaged threads
Refer to Thread Repair (6.2L LS3) (81. Thread Repair) or Thread Repair Specifications (6.2L LS3/7.0L) (Thread Repair Specifications) Thread Repair Specifications (6.2L LS9) (Thread Repair Specifications).




3. Inspect the cylinder head for warpage. Refer to Engine Mechanical Specifications (6.2L LS3) (Service Limits & General Specifications) Engine Mechanical Specifications (6.2L LS9) (Service Limits & General Specifications) Engine Mechanical Specifications (7.0L) (Service Limits & General Specifications).




4. Cylinder heads that have excessive warpage or a damaged sealing surface can be machined as required. Determine the cylinder head thickness as measured from the cast in place machining pads (1 and 2) to the head deck sealing surface. A cylinder head that measures less than 6.88-7.11 mm (0.271-0.280 in) (a) cannot be machined and must be replaced.




5. Use the J 9666 - Tester in order to measure the valve spring tension. Refer to Engine Mechanical Specifications (6.2L LS3) (Service Limits & General Specifications) Engine Mechanical Specifications (6.2L LS9) (Service Limits & General Specifications) Engine Mechanical Specifications (7.0L) (Service Limits & General Specifications).




6. Inspect for a leaking plug. Production applications use a rivet-type plug (1) at the top rear coolant passage of each cylinder head. If service of a leaking plug is required, it is necessary to remove the cylinder head from the engine to properly remove the plug. Refer to Cylinder Head Disassemble (52. Cylinder Head Disassemble)