Rods/Piston
 

I had a machine shop press some new Wiesco pistons onto a set of stock rods (two dots rods) and I noticed that some of the rods were a little purple-ish brown on the end were the wrist pins were pressed onto the rods. I should mention all the rods are a little brown-ish on the wrist pin end where they heated them to press the wrist pin on for the pistons, but I thought if they got too hot (the purple-ish color) that this actually fatigued the rod and potentially ruined the rods. My experience was that they heat the rod a little in an oven and freeze/cool the wrist pin and then quickly slip the wrist pin, rod, and piston together before each one either cools or warms up, but they never heated them up to high temperatures. Any idea if my rods are now any good?

Re: Rods/Piston
 

Hard to tell without seeing pics? It also might be marker dye cooked on the rod ... some use the dye during balancing and such?

Re: Rods/Piston
 

Ken, thanks for the help. Here is a picture, what do you think?

Re: Rods/Piston
 

Did they polish the rods or shot peen them? If so, that might be what you are seeing there ... it does look like they were "blued" by heat, but it's hard to tell ...

Re: Rods/Piston
 

Ken, they polished the rods, but never shot peened them, what do you think?

Re: Rods/Piston
 

Personal opinion is that they'll be fine. It looks to me like the discoloration may have come from polishing and then the inductive heating they use for pressing the pins.

Re: Rods/Piston
 

Ken, thanks, two other people said the same thing, so it is good to hear you confirm what they said.