M20 Single mass flywheel material?

[TobyB]

Just remember that even something that is "forged" starts its life as a casted item.

Yeah, but the initial metallurgy of a forging's different, too- you wouldn't forge
something cast of grey iron (like the block is) since it would certainly crack on cooling,
but a mild steel gains a LOT of strength for a minor loss in ductility when you forge it.

And it's improving a lot more, and faster, than I realized....

t

[Northern]

Rods are almost always sinter forged. From my understanding, that process can leave what look like casting lines/flash if there's any excess material. I can understand why people think they're cast.

[nando]

yeah, cast rods pretty much don't exist. Maybe in a lawn mower engine but I doubt even then. The metallurgy just doesn't work.

Makes me wonder how many rods he's "seen" if he believes they were all cast - because they almost certainly werent. One thing, you can bend a rod - because it's forged steel, not cast iron. A cast iron rod would just crack (yeah, you can "break" a rod if you bend it past it's yield point, but that's another topic).

It does make it fun to chuckle a little at people who buy into marketing - aftermarket forged rods etc. Often, the stock rods are actually just fine (and nearly always forged, I don't know of any BMWs that aren't), the main advantage you get with an aftermarket rod is less weight.

[ForcedFirebird]

It does make it fun to chuckle a little at people who buy into marketing - aftermarket forged rods etc. Often, the stock rods are actually just fine (and nearly always forged, I don't know of any BMWs that aren't), the main advantage you get with an aftermarket rod is less weight.

M20 rods are definitely forged, and quite strong. I would rather a heavy m20 rod than a powder forged late model rod - which wouldn't stand up to this like an m20 did (hydro-locked)...

[AndrewBird]

Flywheel is cast STEEL, not cast iron. Huge difference.