Head gasket why two

[Allen Kamfonik]

Hi all,
I’m new to the world of Atomic 4 engines. Just recently I purchased a 27 foot Oday with an Atomic 4. I also purchased an Atomic 4 with a cracked block to learn how they tick. I pulled my good motor out of the boat pulled the manifold, starter, side plates and head off. I flushed out the block water jacket and removed about two cups of silt. The cylinders have been sitting in mystery oil for weeks. Motor rolls and cylinders look good, but one intake valve was stuck open. I removed the valve and cleaned it with steel wool and reinstalled it. I have currently cleaned the surface had the head cleaned and resurfaced. I just ordered my gaskets, thermostat kit with new bronze housing. The question I have is why two head gaskets??? I’m thinking valve clearance issues??

[Don Moyer]

Allen,

Universal used two head gaskets to approximate the thickness of the original copper-clad asbestos head gaskets when they were no longer available, so as to retain the original compression ratio of 6.3 to 1. When the Victor gasket company designed the excellent steel-reinforced graphite gaskets which have been in common use since around 1995, they used the same rationale.

Many folks are concerned that the use of two gaskets will reduce the available power from the Atomic 4. One of the things that is so interesting about the Atomic 4 is that you do not gain or lose power by small adjustments in compression ratio on either side of 6.3 to 1, as long as you readjust the ignition timing at your favorite cruising power setting to best RPM.

Don