Russ Murphy

[quote] You can bump it up a level by taking the powder metal preform and heating it to intiate sintering. The hot preform could then be put in a metal die and pressed to the final shape. This makes a very strong part and uses nearly 100% of the metal. Pretty close to a forged part. <hr></blockquote>

Alan is this what someone in the bike industry would call a "melt-forged" part? They're usually talking about aluminum crank arms when throwing that term around.

marksportcts

So none of the 944 rods are sintered then? My machinist told me that my rods were sintered.

Danno

"For a sintered rod you's start with a powdered metal. Less dense and apply force in a hydrogen atmosphere."

What does the hydrogen do?

Alan C.

Melt forge in aluminum. Might be a pressure cast part. The part is cast first and then subjected to pressure while cooling. This is done with some wheels.

The hydrogen atmosphere prevents any oxidation, it's a reducing gas, which would impede the diffusion. It is also better at heat transfer.

As to 944 sintered rods I'm not sure if they made any or not.

Alan

John Anderson

86 and 87 had forged rods..they used the cast rods in the later models...I have been told the reason for this is (and this was a rumor told around the water cooler), that Porsche used what they had on the shelf for the 86 model, for the 87 and then ran out, and went to cast after that. Just a rumor guys, just a rumor.

But I know 87's have forged, mine does, or did rather, now it has Pauter Rods and has been sold.
Take Care!

Loki

My partner in crime works for HirschVogel in Ohio, daughter company to the one in Germany. They are a Cold/warm forging company. The numbers Alan gave look pretty accurate. All I know is the metal is red hot when pressed. The hydraulic presses are about 30ft tall and the mechanical ones have 12ft flywheels(they make real flat pennies). After the parts are pressed they are then heat treated and cooled in the manner Alan described to prevent oxidation(causes scaling).
I'd have to guess Alan is an Engineer(not the hat wearin/whistle blowin kind).

Chris '86 951

Matt Sheppard

I heard rumor that the '83 NA used forged rods as well. Any body know for sure (John?)

John Anderson

I don't recall seeing forged rods in the earlier blocks we have torn down. Maybe they mixed them up a bit...???

Silverbullet951

Alan, why do they use hydrogen? Why not another gas (other than oxygen)? Why not noble gases? Just curious

Alan C.

Hydrogen creates a reducing atmosphere and it is good for heat transfer.

Alan