Oil Pump Gear - Crisp on the Edges, Tender in the Middle

[48lesco]

Oil pump gear looks like it got hot on the edges. Do these always look this way? No other evidence of overheating anywhere in the pump or engine.
Thanks for any insight!

[LOUD MOUSE]

It's OK.
That's the way HONDA issued it. ...................lm

Oil pump gear looks like it got hot on the edges. Do these always look this way? No other evidence of overheating anywhere in the pump or engine.
Thanks for any insight!

[48lesco]

Thanks LM - just wanted to be sure since it could "knacker" the crankshaft. I love that word - learned it on this forum.

[djohns]

LM is correct, as usual. The discoloration is due to the induction hardening. They use a high current flowing through a circular device in this case, and the part is put in the center of it. The intense magnetic flux induced in the part causes it to heat up It handens the teeth but allows the web to keep its softer properties. Most gears are done this way and only takes a few seconds instead of the hours needed for nitriding. Look at the teeth on a good quality hand saw and you will see the same color pattern.