Why is one 340 connecting rod bronze color?

nm9stheham said

Well, you know, oxy-acetylene and TiG steel welding rods are copper coated to keep them from rusting.... and that works just fine; I have had some hanging around for a decade or more and are still fine to use. So the idea of corrosion resistance has some basis to it. Maybe these are for marine use??

Click to expand...

This is exactly the reason.

If it is coated to add material and to "tighten up" the pin or rod journal end then why is there no copper on those surfaces? Because it's coated then machined. If it was added after machining to tighten it up then those bores would still have copper colouring. Even the rod in the video posted was machined steel on both ends.

I believe they were coated for preventing corrosion BEFORE installation while they waited in some bin somewhere in a warehouse or factory. J.Rob