Method to increase local cooling rate and improve material properties in a low-pressure sand-casting head

A method for low-pressure sand-casting a cylinder head of an automobile vehicle engine, comprising:

• creating a port in an automobile engine cast cylinder head low pressure sand-casting mold;
• applying a compressible material coating having graphite and carbon fiber on a metal core of a manifold port metal core assembly, wherein the compressible material coating includes an inner layer disposed on a first end of the metal core, a through-shell sand core disposed on the inner layer and having multiple through-thickness passages defining holes or open channels, and an outer layer disposed on the through-shell sand core;
• predetermining an initial thickness (t) of the compressible material coating at least equal to a compression amount of the compressible material coating anticipated due to shrinkage of a casting material located proximate to the port and surrounding the compressible material coating as the casting material cools;
• and
• inserting the manifold port metal core assembly into the port prior to filling the cylinder head sand-casting mold with the casting material.