Shim-Dex shims rotate the ground of the spark plug at 30˚ intervals
anywhere within 360˚
Indexing your spark plugs increases power and provides crucial clearance between the spark plug and piston.
You won’t have to buy extra spark plugs to have them perfectly indexed AND Shim-Dex shims are REUSABLE many times over.
Model 14F - for 14mm flat seat spark plugs only
• Minimal or no thread exposure in the cylinder
head that can overheat and cause pre-ignition
• Shim-Dex shims are so thin they will not adjust
the gap too far out of the combustion
chamber and negatively effect