Sulphated ash helps to extend the valve recession. Especially in gas engine or diesel engine because of no liqiud phase flow through the intake valves . Implies no liquid film to absorb the mechincal impact between valves and its seats.
The reason behind ash requiremen is valve design.
For...
Another information.
Even 1 ppm of silicone will degrade anti foam property. Be careful when applying gasket compound (if it is silicone mixture).
Hope this helps
