The W - series engines featured redesigned water jackets for additional cooling, and fully floating piston wrist pins. (en.wikipedia.org)
Hard knocks that happen at startup and go away quickly are a sure sign it is an early failure and oil related to a rod or main knock, piston slap against the cylinder wall and wrist pin knocks will persist after warm up and get worse with engine rpm. (mechanics.stackexchange.com)
Forged Pistons (4)- 9.5:1 Compression - 86 mm bore - 2618 T6 high tensile forged aluminum - ring widths 1.0 / 1.2 / 2.8 mm -.866 x 2.250 free floating carbon steel wrist pins (greddy.com)