How Many Holes???? (Stude V8 Torque Plates)

[Tom Bredehoft]

A well set up Blanchard grinder will leave a flat surface. Any machined surface will be less flat and probably not a match for the head surface.

[PackardV8]

Any machined surface will be less flat and probably not a match for the head surface.

One more time. We're using an automotive machining center to make flat the two head surfaces and the two block decks. The heads and the block are going to be mated. Why wouldn't that same machine make the torque plate flat enough?

jack vines

[Tom Bredehoft]

Just the tool maker in me, Jack, Blanchard is flatter than machined. Perhaps a little lapping compound and four hours of floating the head on the block would mate them.

[PackardV8]

Perhaps a little lapping compound and four hours of floating the head on the block would mate them.

Agree, lapping the head to the block perfectly flat would be interesting exercise, but to what end? There is always the head gasket between the head and block and/or between the torque plate and block. The parts never touch.

Surface finish is also very important too. It's possible for mating surfaces to be too smooth. The higher the temperatures and combustion pressures, the more the head gasket needs some tooth in the head and block surfaces to help hold it in place. For many years, most aftermarket gasket manufacturers said a surface finish of 55 to 110 micro-inches RA (roughness average), or 60 to 125 RMS (root mean square) is acceptable for conventional gaskets.

FWIW, back in the bad old days, Permatex paid Bobby Allison to build a NASCAR Grand National car without gaskets, using only their products for sealing the water, oil and lubricant containment. The only exception was head gaskets were used. Too large an area, too much combustion, oil and water going on there.

jack vines