Technical Powdered metal rods??? A question for the mtealurgists or whomever

OK I guess I could take the time to research this but someone on here knows the answer.

I have pretty basically lost touch with all things "new"-ish. I come from a background of all things obsolete or at least for the sake of argument I do.

I am not grasping powdered metal connecting rods. Like in how are they made, how do they compare to say something like a forged or cast rod? Can anyone help me out here?

 

I did some research and basically they take the powdered (sintered) metal alloy and press it into a die under very high heat and pressure that causes the molecules to form a solid. They test about the same as a forged rod and are a lot cheaper to manufacture. If it means anything there are a lot of guns that have the receivers made of sintered metal and they handle the extreme pressure of large caliber bullets without blowing up.

 

They usually have the added bonus of being "cracked" along the parting line. That means they can't be resized.

 

...huhh...that's what a 'bonus' is these days... The OEM do not use these rods because they are better, rather, they are less expensive to make.
Like many fasteners in the newer cars the rod is a use-it-once kinda deal.

 

Jim, 73RR,
I wondered if they were w throw away rod or not.

 

Car manufactures try to control costs (oh really brain) so they can make a car that the public can afford and also allow them to make enough cash to survive and satisfy share holders, it's amazing how much cost is added to a new car by stuff mandated by the FED's (and I'm not talking about a front engine dragster) all the new cars have an inside emergency trunk release in case some one is locked in by mistake or your wife wants to let herself out I guess? Rear view cameras will be the next mandate I'm betting!

 

Aggie,
Didn't mean to ignore you. I wondered if that was how they were built, so it is metal like the stuff they use to metal spray only instead of spraying it is forced into a mold of so me sort. Maybe not as good as we like but cool idea and they evidently work.

So my take on it is don't buy used powdered metal rods. Correct?

 

Correct, "cracked rods" as we called them are one time use, no rebuilding.

 

"Powder metallurgy" is the process, as opposed to casting or forging.
Like anything else, it can produce some amazing results,
can also produce cheaper results.
Cracked rods and powder rods are used to save money.

https://www.google.com/search?site=...ac.1.49.img..0.13.1355.v2OzsAukCqo&gws_rd=ssl

 

I'm not sure why is it not resizable.

You can't shave the rod & cap & put them back together?

 

If you look carefully, you'll also notice that the lower gear in most timing chainsets is powdered metal.

 

Essentially the powdered metal is filled into a cavity and then pressed under pressure to make the part. Most connecting rods made this way are also forged after having the "blank" made with powdered metal. Its a very interesting process to watch.

Branching off this topic slightly - its this same basic sintered metal powder that is now being used in metal 3D printing machines. Basically a thin layer of powder is laid down, a laser precisely melts the powder, then another thin layer of powder is laid down and repeat. Direct Metal Laser Sintering.

 

You cant because the parting like is not a machined finish, rather just where it happened to break.

 

Interesting, look how many tangs that insert has.

 

You can't resize them but I don't know why you couldn't reuse them if they were not stretched or scored.

 

So you'd need to remove too much metal to shrink the big end?

 

A customer/freind is a tool and die maker at a PM plant, Pretty impresive stuff. The whatever material is a blend that feeds the presses and comes out of the press to almost finnished size with the expantion and contraction that happens in the ovens compinsated for. You can take a part straight out of the press and crumble it like a dirt clod, but once thru the oven its as strong as anything else out there designed for normal use

 

Being some what old school myself something about powder metal and cracked just dont sound good.

 

OK, P'n'B from the old HAMB metallurgist:

dreracecar is correct, the powdered metal is very fine powder that has mix of alloy elements in the powder mix. It is very fragile when it is pressed. The high heat (that is much higher than normal heat treating) is the sintering process where the powder particles diffuse into each other and it creates a result that is very strong and uniform properties. The big advantage is overall cost of the part, due to material efficiency and minimal machining costs, but there are also geometry and mechanical property benefits that can be considered positive.

I do agree that they are generally not reusable except as orig size. I also would not use them in a real high perf application, stick to good old aftermarket forged rods.

 

If you decide to go that route Beano, I'll gladly take all those old antiquated pink rods off your hands, no charge.

 

The interesting thing about them is, both Ford and GM engines now go three times the distance of most motors built just thirty years ago. Three hundred thousand and more is no longer uncommon. No more ring jobs. No more take out some shims to tighten up the rods. No more valve jobs at 60,000 just to make it idle smoother. I'm like the guy above, powdered metal rods?? Cracked, not cut??? It makes my scrotum wrinkle!!

 

They are making blocks out of it now too if im not mistaken.

 

And cams

 

Having the caps seperated from the beams is refered to as "cracking" but the process is far far from sticking it in a vise and wailing at it with a BFH. It is prob located in a fixture that clamps both sides of the big end and then vibrated causeing the split. Having the mateing inclusions both positive & negitive creates the cap alignment.

 

http://www.superchevy.com/how-to/engines-drivetrain/1510sc-howards/?__federated=1

Howard's powdered metal rods.

An excerpt ...
Simply put, these rods are stronger than 4340 forged steel. In fact, Howards says the strength is closer to 300-M, but without the brittleness. That's pretty darn strong, if you ask us. As we finished this story, Howards was just ramping up full production of their Chevy rods, with the first ones offered in a 6-inch length. Other versions are on their way-and likely already available as you're reading this. The rods are made in a Michigan plant, which is close to all the domestic auto manufacturers. We're told they produce about 100,000 connecting rods per day! And as a testament to the durability of powder metal-forged rods, GKN says they have never received a failure complaint of a rod used in an original equipment application. We think that's a good enough reason to try them in your Bow-Tie's performance 350.



Read more: http://www.superchevy.com/how-to/engines-drivetrain/1510sc-howards/#ixzz37kWofzg8

 

OEM "cost saving" shenanigans are usually coupled to volume. It's always been about methods that are much more expensive for small runs but a lot cheaper for huge volumes. That is decreed to be "progress," "the Wave of the Future," "the Next Big Thing," etc. etc. etc.; the other way around they usually try to get outlawed. Or did you think those environmental and safety regulations were about the environment or safety?

Big hype these days is about additive metal sintering. There is potential there, though nothing like the Star Trek replicators starry-eyed geeks are seeing. 3D-printing sintered metal is not quick, and the equipment isn't cheap. But given capitalization of the equipment the cost of a one-off set of rods can be the cost of design and creating the 3D model (if you have a few weeks to spare).

 

The key phrase is "normal use"

 

[QUOTE="31Vicky with a hemi, post:

Howard's powdered metal rods.

An excerpt ...
We're told they produce about 100,000 connecting rods per day! And as a testament to the durability of powder metal-forged rods, GKN says they have never received a failure complaint of a rod used in an original equipment application.



Read more: http://www.superchevy.com/how-to/engines-drivetrain/1510sc-howards/#ixzz37kWofzg8[/QUOTE]

OT engine example are GM's LS 4.8L 5.3L 5.7L 6.0L engines, there are many turboed, nitrous, supercharged examples that have made 800hp to 1000hp with stock shortblocks stock pistons and rings, stock powdered metal rods, stock rodbolts, stock crankshafts and even some of them have stock heads with upgraded valvessprings.
I believe what 31 Vicki with a hemi posted as I personally know of a OT turbo drag car with a stock longblock 5.3LS out of a truck that made over 100 passes in the 8.60 to 8.30sec range in the quarter mile before an aggresive tune burned a factory piston and bent one rod, but the rod didn't break at the1000hp the car was making and the car still wen't 8.50's on that pass. I wouldn't hesitate to use powdered metal rods in any engine I was going to build. Another thing to consider is by cracking the rod cap like the manufacturer does, the un-even surface created between the rods cap and the rod acts as positive stop helping with rod cap walk, which is a good characteristic to have in a strong rod. I have drilled and dowel pinned my main caps on my 2 bolt main engines I was gonna lean on for the same reason, it helps with cap walk.


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Not So!!!
Bearings are produced with the od oversize to accommodate the larger honed hole in the big end. Done quite often.

T

 

This would seem the best alternative to tossing the rods.