Pendulum piston has a complex high quality heat-resistance steel head, with special cooling oil-ways and latest combusting chamber. Special-shaped pinholes are assembled with bronze sleeves. Enormous explosive pressure is transferred directly to piston pin and connecting rod through piston head. The piston skirt is made of cast duralumin. Heats of steel head will not be directly transferred to aluminum skirt. The thin-walled aluminum skirt can compensate non-uniform thermal de-formations and has less clearance between skirt and cylinder therefore has better guide ability.