| • | J 8089 Carbon Removing Brush | 
| • | J 9666 Valve Spring Tester | 
| • | Improper installation | 
| • | A loose or warped cylinder head | 
| • | Missing, off location, or not fully seated dowel pins | 
| • | Low torque on the cylinder head bolts | 
| • | Cylinder head bolts with the incorrect length | 
| • | A warped engine block surface | 
| • | Scratched surfaces | 
| • | Excessive intake manifold torque | 
| • | Cracked engine block threaded holes | 
| • | Porosity | 
Caution: Wear safety glasses in order to avoid eye damage.
Important: Do not scuff the chamber.
| • | The gasket surfaces | 
| • | Do not use a motorized brush on any gasket sealing surface. | 
| • | Valve stems and heads on a buffing wheel | 
| • | The bolt hole threads | 
| • | Remove all dirt, debris, or threadlocking material from the bolt holes. | 
Replace the spring if the spring tension is not within specification.