GregBBRD

Thought you guys might enjoy a couple of pictures of 928 high performance cranks being built. I've learned a bunch, since I "tore" up all the old blueprints for my stroker cranks and started over.

Making a crankshaft from a chunk of raw material isn't a "ten minute" job. It is very involved and very difficult. It requires a lot of separate machine operations....on an entire shop full of different kinds of machines.

Here's a picture of a cart full of 928 cranks just back from the first heat treatment. They are hardened to "around" 40C at this stage. They started out as a solid chunk of very special steel. They are getting ready for the oiling holes to be drilled. All of the rod and main journals are "roughed" to size. Basic counterweight shape and size is aready roughed in. Holes are drilled and tapped.



Here's a picture of one crank mounted on a simple milling machine, getting the position for the oiling holes marked. I took this picture, because you can see the basic material that the cranks start from, on the ground behind the mill.

Shark_Week

oh my god!!

namasgt

Greg,

Are those clear lines on the painted blue journals actually machined ?
If they are, will they stay there?

GregBBRD

No, they are just lightly scribed into the surface of the Dykem.

Regardless, the journals are just "roughed" in. They have been ground, but not on a "finish" grinder.

I was there to check/adjust the size of the counterweights with my "new" rod design. The rods fit onto the crank, without the bearings, so I'd guess that the journals are about .050" oversize, at this point.

namasgt

Am I seeing correct that there are 8 counter weights like the GTS cranks vs. 6 counter weights of the older design stroker and pre GTS cranks?

86'928S MeteorGrey

Beautiful.

GregBBRD

Since these crankshafts are designed for higher rpm use, there are actually 6 full counterweights and two "pro-stock" style counterweights. If you "dig" really deeply into the reasons for adding material to the "center" throws, the reason for adding this material has very little to do with "balance" or "smoothness".

Most "high end" crank builders will not make a crank, these days, with 8 "full" counterweights, unless the customer insists. Just a bunch of "extra worthless weight" slinging around, inside the engine. I talked to Whitey at Moldex, ten years ago, about adding two more counterweights to my 6 counterweight crank and he flat told me that this would be "stupid", considering the rpms these engines were turning. However, current camshaft, intake, and head design has "added" the ability to "twist" the 928 engine to higher rpms...which requires different thinking.

Anyway, 8 full counterweighted cranks are pretty "old" technology. Keep in mind that the GTS cranks were designed more than 20 years ago!

Stop and think about how far engine design has come, in the past 20+ years!

As I mentioned, these cranks are absolutely "new" in terms of design. Of course, the length and the basic rod and main bearing location doesn't change...but certainly, everything else has.

Andre Hedrick

Off to the men's room with that kind if car ****!

Dave928S

They're a work of art Greg ... a precision engineered lump of steel is a beautiful thing. How many did you get made in this lot?

FBIII

Are they any lighter than previous cranks?

Koenig-Specials 928

With this kind of committment our cars can live forever. Excellent work.

Fabio421

Wow! Pretty cool. The major new components that are being made for these cars these days is truly amazing.

SeanR

If you are needing test subjects, I can send you my car.

SMTCapeCod

At what cost, though?

Time will tell.

Great to see just the same~~~

Koenig-Specials 928

Well, as Fabio's avatar says in the previous post,

........... is like a hot stripper. I just keep throwing money at her and hope that someday she will give me the ride of my life......

Same sentiment here