(a)Cylinder head. The joint between the cylinder head and
block of the engine shall be fitted with a metal or metal-clad gasket
satisfactory to MSHA held securely in position by through bolts or other
suitable means to prevent a change in alignment. This joint shall provide an
adequate flame barrier with the gasket in place.
(b)Valve guides. Valve guides shall be long enough to form
an adequate flame barrier along the valve stem.
(c)Gaskets. All metal or metal-clad gaskets shall maintain
their tightness during repeated explosions within the engine and its intake
and exhaust systems to prevent the propagation of flame.