I recently purchased some rods off of eBay. The seller listed them as forged, but my machinist told me they are cast. The seller is trying to claim that 2 different machine shops told him that GM never made any forged steel rods, only forged iron. This does not sound right. There is casting material sticking out on the large end (on opposite sides where the rod bolts are). The other problem is that he claims the discoloring (blackened metal) is from use in a 400 HP motor. I believe that his machinist overheated the rods when the piston pins were pressed in. (The discoloration is only on about 3 or 4 of the rods, not the entire set, which is why I don't buy his claim.) There has also been extensive grinding done on the small end (possibly for balancing) & one side of the end (on several of the rods) is VERY thin now (I do not want to take a chance of them breaking). If anyone can give me more info to help with this, I would greatly appreciate it. All I want to do is get a refund, but he is unwilling to bend, saying that they were sold as-is, with no warranty (that can only be enforced if ALL details of the rods were fully disclosed). Thanks in advance.

As far as I know, with the exception of the new pressed powder rods, all Chevy rods are forgings. I have personally used rods that were pretty thin on the pin end with no problems. But how thin is 'thin'?

ww,
How about some pictures ? GM never made a cast rod for a Chevrolet, they are all forged. The new powdered metal rods are also "forged" but a different process. Some discoloration from heating an the small end is ok, you can check the press fit with a bore gauge. As far as the grinding goes, its hard to say without seeing them. I have seen them ground pretty thin without any problems.
My only comment is I cannot imagine buying a set of used Chevy rods when you can get a new set of Eagle or Scat ones for around $200.

I finding it hard to believe that GM would forge all of their rods (if so, their forgings look horrible), when casting is much more cost efficient. (The majority of GM crankshafts on the road are cast, so why would they spend all that extra money forging rods?) As for not buying new ones, I am on a very tight budget, so that is why I don't buy new ones. I can provide pictures, but haven't found out how to do that in here yet. I just don't want to take a chance on this particular set of rods, which is why I am trying to figure it all out.

Upload your pictures to here http://www.imageshack.us and then copy the link they provide and paste in in your post.

I finding it hard to believe that GM would forge all of their rods (if so, their forgings look horrible), when casting is much more cost efficient. (The majority of GM crankshafts on the road are cast, so why would they spend all that extra money forging rods?) As for not buying new ones, I am on a very tight budget, so that is why I don't buy new ones. I can provide pictures, but haven't found out how to do that in here yet. I just don't want to take a chance on this particular set of rods, which is why I am trying to figure it all out.
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Regardless of weather you find it hard to believe or not, both Ken & Bill speak the truth & both know what they are talking about.
Chevrolet rods are all forged.
And sometimes, at least in my opinion, you are way ahead to spend a bit more on good parts, especially the most highly stressed part in your engine,, once rather than buying things twice :sad:

GM didn't!!

In 1973, Cad. 472/500, Buick 350 and all V-8 Pontiac's used "ARMA STEEL" cast rods.

And if you check, they are ALL what we would call "low rpm" engines!!

But NO Chevy cast rods!!

pdq67

wacko,
If you edit your post, or make another reply here, go way down past the bottom of the reply page and you will see a section to "manage your attachments" Thats where you can add your pictures. By the way, you have to do this with a "full" "post reply" button, not the quick reply button.

the cost difference between casting or forging a crankshaft is much more significant than the diff would be on a rod. you can spank out a rod from bar stock to pretty near net shape with a forging in a couple hits and get the bonus of the much better strength. not so easy with a crank. you have to be moving and trimming a whole lot more material in forging a crank vs pouring it into a mold. just think about the geometry of those components for a minute and i think you will see what i mean. then think about the stress they both see, that crank is being loaded across a pretty short section, secured with heavy block webs and caps that arent that far away from the force; while every pound of torque that engine is producing is trying desperately to throw that rod right out of the engine. and the rod aint got nothing but itself to hold it together.

Cranks aren't dealing with forces trying to pull them apart. Bend, yes, but not pulled apart. Thanks for jogging my memory, pdq - I though I'd remembered some of the earlier manufacturers using cast pieces. I sure agree with BillK here, I can't see using heavy factory pieces when new aftermarket rods are available inexpensively, but if you got a great deal on em, power to you. Good luck with your build.

That makes sense, but I was always under the impression that stock rods were cast. I wasn't meaning to come off as sounding like I was questioning anyone's integrity, I was just wanting to get to the bottom of things. However, with the grinding that was done & the discoloration on a couple of them, I think I am going to break down & buy some new Scat rods. Thanks for everyone's help.

That makes sense, but I was always under the impression that stock rods were cast. I wasn't meaning to come off as sounding like I was questioning anyone's integrity, I was just wanting to get to the bottom of things. However, with the grinding that was done & the discoloration on a couple of them, I think I am going to break down & buy some new Scat rods. Thanks for everyone's help.
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:thumbsup:

All I want to do is get a refund, but he is unwilling to bend, saying that they were sold as-is, with no warranty (that can only be enforced if ALL details of the rods were fully disclosed). Thanks in advance.

Good luck with the refund on Ebay. I had asked about some 3.73 gears for my truck, if they were 3 or 4 series, and the idiot replied 3 series. I get them and they have GM stamped all over them. GM 4 series is 3.73 and up on trucks. I filed complaint, paypal case, etcs. Even sent them back as per the paypal instruction, and the guy rejected them, costing me an extra 25 bucks for shipping. I never got the refund, and I ended up chunking the set due to a chip in the pinion happened during shipping back to me.

GM didn't!!

In 1973, Cad. 472/500, Buick 350 and all V-8 Pontiac's used "ARMA STEEL" cast rods.

And if you check, they are ALL what we would call "low rpm" engines!!

But NO Chevy cast rods!!

pdq67

Wacko, I have never heard of cast rods, until these that pdq67 mentioned. And they are obviously very rare. So, if these rods are actually Chevy rods, then that means your machinist should be your ex-machinist.

Forgings always have a wider parting line (the material that gets into the seam between the top and bottom of the forging die) than does a casting. The parting line on a connecting rod will be about 1/8" wide, proving it is a forging. The parting line on a casting, such as an iron crankshaft will be very thin by comparison, probably about 1/32", but maybe a 1/16".

There is no such thing as "forged iron". Iron is cast, sometimes with heat treatments such as austempering done afterwards. Steel can be cast or forged.

What is the ebay item number? That would help us give you more answers.

Ken