| After testing these out on other projects I decided to get a set for one of my TTs. They are pricey, fully custom to thickness and bores. It has raised copper O-Rings on both sides of the gasket.
The water hole size at each water port or the water restrictor holes in the gasket are the same size as the stock gaskets water holes. The O-Ring seal that encapsulates the entire waterway allows the coolant to be exposed to more of the deck and head surface aiding in the cooling process helping to eliminate localized hot spots. Also being that less gasket material surface ara contacts the head and block the clamp force is raised. This is what the designer says: "When a force is applied to a bolt or stud it is distributed over a certain surface area. To increase pressure it is necessary to either increase the force or decrease the area over which the applied force is being distributed. To double the force it would more than likely stretch the bolts as a permanent elongation would take place known as the permanent set. Tripling the force and exceeding the ultimate tensile strength of the bolt or stud would cause it to fracture or shear off. Using a bolt or stud with a thicker shank and quadrupled force, this would lift the threaded bosses cracking the block surface and warping it destroying any chance of a good seal. What we have done is to reduce the surface area to be clamped by up to 700% which has the same effect as increasing the applied force."
|
A custom copper head gasket? - 
