forged type 4 crankshaft at aircooled.net

Wally · Post by **Wally** » Fri Jan 09, 2004 2:22 pm

Hi Jake,

You may or may not know that aircooled.net has forged cranks for sale for $1250,-- I believe.
Do you know if those are any good? Have you used those before? Are they Scat?
I ask you because you did mention problems with Scat type 4 cranks before iirc. Machining not up to par it was I believe.

Thanks in advance,
Walter

MASSIVE TYPE IV · Post by **MASSIVE TYPE IV** » Fri Jan 09, 2004 2:36 pm

They are billet.... I just got an 86 for my engine, and an 80 for a customer. so far so good. There is a limited supply

Wally · Post by **Wally** » Sat Jan 10, 2004 2:13 am

Pity, I was hoping they were a true forged item.
Was thinking that if you don't have a cam to worry about (with OHC), clearencing would be a bit easier

Thanks,
Walter

Guest · Post by **Guest** » Sat Jan 10, 2004 8:17 am

a billet crank IS a forged crank; that's the nicest crank you can get short of a $2k billet crank (next step up).

John

Wally · Post by **Wally** » Sun Jan 11, 2004 8:19 am

Hi John (the one from aircooled.net I presume),

I always thought that a billet crank was just machined out of a huge hump of material and that a forged crank was forged into the rough shape of the crank and than machine finished.

Please explaine if I got my definitions wrong

Thanks,
Walter

Guest · Post by **Guest** » Sun Jan 11, 2004 9:24 am

You are correct. But I ask you this; Jake's 3.0L is going to be a BEAST right?

Then why is he using a billet crank if they are weaker but cost more?

John

raygreenwood · Post by **raygreenwood** » Sun Jan 11, 2004 10:40 am

You guys are dancing around terminology. The "billet" cranks are machined from a billet that has been forged...or struck in a forge for much improved grain structure, and then machined. The VW crank, which is also forged (VW has never used cast cranks in the aircooled engines to my knowledge)...is one that is made in the opposite direction but by the same method. A hot billet is repeatedly struck when glowing hot, by dies that makes its crude shape closer and closer to the form outline of the crank. Then it is machine finished. Both of these are totally different from a cast crank, which is cast into the rough shape, machined, heat treated and machined for final. This is common, but may not be exactly how this particular crank is made so correct me if you have better information please. Ray

Alpine · Post by **Alpine** » Sun Jan 11, 2004 1:31 pm

Anyone know of some good books on automobile manufacturing processes? There's not much in my tech-school books and most of what I know is from watching car shows on TV ...

MASSIVE TYPE IV · Post by **MASSIVE TYPE IV** » Sun Jan 11, 2004 6:04 pm

Yep, the billet crank is made from a huge chunk of forging.......

I just used it in the 3.OH to make the engine worth more when I decide to get rid of it..... thats the truth!

Honest to god truth is that someone gave me a good deal on the Scat crank BUt I still have a DPR 86 that was going to go in the beast- thats really all it needs anyway!

Wally · Post by **Wally** » Sun Jan 11, 2004 11:12 pm

Anonymous wrote:You are correct. But I ask you this; Jake's 3.0L is going to be a BEAST right?

Then why is he using a billet crank if they are weaker but cost more?

John

Thanks John,
I am really considering that crank, but was a bit worried because Jake's engine will - from what he told us - be a real torque monster, not a revver.
My big engine should also really rev as I may have found the right heads for it that flow accordingly. Thanks also for your honesty Jake (as usual).

Its a good deal I suppose and I just measured in a test fit that my cylinder has 18,0 mm deck height with my current 80mm stroke crank and 5,7" rod...so plenty length left.

Greetings,
Walter

Frallan · Post by **Frallan** » Mon Jan 12, 2004 11:52 pm

Ray,

You surprise me with a definition that I never heard of.
I have seen many Billet cranks in dragracing and in Swedish autocross including VW T1 wich are billet in my term of definition.
It is a billet round bar that is machined from scratch to the right dimension.
Cutting through grain structure and still becoming a very strong crank.
Your definition of forged I fully agree on.
What is best? Must be very marginal as you find Top Fuel 6000 hp + engines with billet cranks (my definition) and they hold together for at least some seconds......and also forged.
If I had to put my money on it, I would ofcourse say that an optimised forging is best.
The full story is ofcourse not just these parameters but all other choices of original materials, heat treating, releiving of stress and design through good fillets and more.

Doesn't or hasn't Scat done all three varianst of cranks?
Forgings, "semi billet" and billet?

raygreenwood · Post by **raygreenwood** » Tue Jan 13, 2004 5:48 am

When they make steel, aluminum, bronze etc....any metal, they have a whle series of names for shapes and sizes of raw material as it comes out of the "bloom" of the mill. I can't remember all of them off the top of my head. Billet simply describes a chunk of metal (there are other details of definition as well).

You can have forged billet, cast billet, rolled billet. The best forging is the classic forging wherin the final rough shape of the part is actualy made by strikinjg it into progressive dies. How much into the part you are allowedto machine befors you disturb certain grain structures can be an issue as well.

You need to have the original billet very hot to do that type of forging. Others, take delivery of billet that has been struck repeatedly but not yet in a mold. It makes the grain structure tighter and makes the steel more dense overall...but yes cutting into it will cross grain structures. Its not as strong as pure forging. Another similar method is to rough machine the shape from billet...and then repeatedly strike into dies when heated to improve what you have. Thats how a lot of tools are made. Ray

GhiaMonster · Post by **GhiaMonster** » Tue Jan 13, 2004 7:16 am

Alpine, here's a cool site that shows how alot of things are made. For an
example of forging, go here and click on How Everyday Things Are Made.
Forging is under Processes.

Guest · Post by **Guest** » Tue Jan 13, 2004 8:10 am

Excellent feedback from both you Ray and the sites from Ghiamonster.
For me sorted out.
I hope also for everyone else.
Thanks!

Alpine · Post by **Alpine** » Tue Jan 13, 2004 9:47 am

That site is awesome, GhiaMonster. Thanks!