Walnut Blasting: Curing Direct Injection Intake Valve Carbonization

In traditional port-injected engines, fuel constantly sprays over the intake valves, washing away oil vapor residues. In direct injection engines, fuel is injected directly into the combustion chamber, leaving the hot intake valves completely exposed to crankcase oil vapors.

Crushed walnut shells (grade 18/24) provide the ideal hardness: tough enough to shatter baked-on carbon crystals, yet softer than the aluminum cylinder head and steel valve stems, ensuring zero surface damage.