- The piston is 87mm, that's 1mm larger in comparison to the regular 86mm, and the fabric is light-weight and strong A4032 solid aluminum alloy. The desired clearance of 0. The RB26 contains a cast-iron block and aluminum heads, offering a great platform for monstrous ability figures. Two parallel Garrett https://nissanskylinerb26enginefo84715.techionblog.com/28276721/nissan-rb26-engine-an-overview