Bluing on rods - are they ok?

[nwimbush]

Can anyone share some experience with rods? I bought a couple of 454's, one .030 over and one original bores and the rods have some discoloring from heat. The one on the left is pretty much what I'd expect to see, with a little bluing immediately around the pin hub. The one on the right has bluing all the way down to my wife's toothpick. Should this be a cause for concern? I'm not expecting more than about 350hp each, so can I safely run with these for a season?

[Ruaraidh]

Is this a floating or semi-floating pin?

ie does it have circlips holding the wrist pin into the rod or is the rod tight in the rod end and free to float either way in the piston?

Reason I ask is that semi-floating pins are put into heated rod ends and then as the rod cools they are locked into place. This would result in the blueing you are seeing as a normal part of the production process.

If they are fully floating pins ie with circlips and a bush in the rod eye, then you need to remove the pin and inspect the bush. If the bush has worn severly or the oil feed is marginal then this would explain the blueing you are seeing. If the rod is this blue (and is a floating pin design) then I would expect that the small end eye is toast.

[nwimbush]

Originally Posted by Ruaraidh

Is this a floating or semi-floating pin?

ie does it have circlips holding the wrist pin into the rod or is the rod tight in the rod end and free to float either way in the piston?

Reason I ask is that semi-floating pins are put into heated rod ends and then as the rod cools they are locked into place. This would result in the blueing you are seeing as a normal part of the production process.

If they are fully floating pins ie with circlips and a bush in the rod eye, then you need to remove the pin and inspect the bush. If the bush has worn severly or the oil feed is marginal then this would explain the blueing you are seeing. If the rod is this blue (and is a floating pin design) then I would expect that the small end eye is toast.

The wrist Pin is fixed within the rod end - i.e. a press fit, which is why I expected a little bluing from when the rods were heated to accept the pins. It just appears a lot further down the rod on the second engine. These are the rods that I'm nervous about.
I have the blocks in at machine shop, and the shop owner is new to me, so I don't have a great confidence level with his advice yet. I wanted to get some opinions before I listen to yet another sales pitch from this guy....

[Ruaraidh]

Well for me, blueing of the rods from the small end down to mid rod is quite normal with induction heated rods with a freeze fitted wrist pin. The process is quite variable so I wouldn't worry about it being different from one engine to another.

If the rod was heavily blued around the big end or the small end when fitted with floating pins then I'd worry.

There is no mid rod heat source and your piston all looks fine (no blackened undercrown or ring pack blow by so I'd say all was well.

HTH

[nwimbush]

Originally Posted by Ruaraidh

Well for me, blueing of the rods from the small end down to mid rod is quite normal with induction heated rods with a freeze fitted wrist pin. The process is quite variable so I wouldn't worry about it being different from one engine to another.

If the rod was heavily blued around the big end or the small end when fitted with floating pins then I'd worry.

There is no mid rod heat source and your piston all looks fine (no blackened undercrown or ring pack blow by so I'd say all was well.

HTH

Thanks. I'll run them for a year with the stock cams and upgrade next year, when I saved some $