Stage 2 Turbo Project - Crankshaft Nitriding & Journal Polishing

Most stock OEM steel crankshafts have been induction hardened, which is actually a low cost process in which the surface is heated by a high frequency alternating magnetic field that generates heat in the crank's surface quickly before being quenched.

Because of the uneven heating and cooling due to cost saving reasons, the crankshaft hardening process creates a lot of stress within the crankshaft. While it is an ideal hardening process for stock applications, but it is really less then favorable for high performance/racing applications.

Hence, we had the stock 1NZ-FE crankshaft sent overseas to be nitride coated and its now back and ready for us to assemble it along with the engine rebuild. Nitriding is a chemical hardening process in which the part is heated in a furnace, the oxygen is vacuumed out, and nitrogen is introduced which penetrates the entire surface.

The result? An extremely hard surface which will give us a peace of mind when we increase the rev cut to well over 8,000+ RPM, allowing us to stay at the redline level without any worries even under hard boost.

If you're wondering what was the material used, its titanium aluminium carbon which gives the black surface you are seeing in the pictures. Read more about it here.

The color of the crank is now different

A closer look will give you a dark bluish purple look

We also took this opportunity to have the crankshaft journals micro polished, a process where the surfaces are made clean and smooth so that it reduces the friction, allowing the rods to spin a lot more easier and faster.

The end result? A high revving friendly engine to go along with the other parts :)

Surface of the journals are now clean and smooth

Close up shot