Any experience with the AA forged crankshafts? Options

[stugray]

I am looking for a good 2.0L stock crank (71mm).

It is for my race engine, so I would rather have forged than billet (like the SCAT product).

Who has used a AA forged crank? Any issues?
Do we know if these are brand new or reconditioned to be "new"?

Anything to worry about or better options?

https://aapistons.com/products/counterweigh...qxoCrTYQAvD_BwE

[Mark Henry]

They are OK but softer than a german crank.
Two schools of thought with racing, a non-counterweight crank spins up faster vs a counter weighted crank is smoother, longer bearing life, especially with a lightened flywheel.

What I would do is stick with a german crank, might get the german crank counter weighted. A german crank is stronger, less flex and harder journals than an AA (any china) crank.
Then do a full engine balance to +/- 1g, whole assembly fan, crank, fly and PP plus rods end to end.

I don't know what's available for a stock crank but H beam rods are almost 200g lighter than the heavy 2.0 rods.

[aggiezig]

In my 2056 rebuild, I bought a DRD Racing Heads 4340 Forged C/W crank. It was expensive but supposed to be great quality. However, when searching just now for a link, I was redirected to EMPI.... I'm guessing DRD was bought out.

DPR machine shop is a good source to look for a german c/w crank. They take OE cores and weld / machine them to spec. Great reputation for quality work

[wndsrfr]

Check out FAT....they have new forged 80mm cranks from a supplier they've used for ten years or more. For my 2316 they paired it with the flywheel & put in five dowel pins!

[Mark Henry]

Pretty sure the new cranks are all the same manufacturer, or at least the raw forging is.

[zig-n-zag]

A 66mm crank can be made into a 71mm crank by offset grinding the rod journals.

[mgphoto]

39K miles on the 71 mm crankshaft from AA Pistons, no issues so far.
DRD sold his tooling to EMPI and closed up shop.
He did good work, I have a set of his heads.

[stugray]

A 66mm crank can be made into a 71mm crank by offset grinding the rod journals.

I was wondering if I could have a 1.8L crank ground down to a 2.0L crank. If the people doing the work can add a little weld to the outside of the journals you should be able to.

I have TWO 1.8L cranks (paperweights) on my shelf.

[mgphoto]

A 66mm crank can be made into a 71mm crank by offset grinding the rod journals.

I was wondering if I could have a 1.8L crank ground down to a 2.0L crank. If the people doing the work can add a little weld to the outside of the journals you should be able to.

I have TWO 1.8L cranks (paperweights) on my shelf.

1.7 and 1.8 both 66 mm same crank.

[Mueller]

A 66mm crank can be made into a 71mm crank by offset grinding the rod journals.

I was wondering if I could have a 1.8L crank ground down to a 2.0L crank. If the people doing the work can add a little weld to the outside of the journals you should be able to.

I have TWO 1.8L cranks (paperweights) on my shelf.

No need to add material. The new journal has a smaller diameter and will have an axis further away from the crank centerline for the longer stroke.

[Mark Henry]

A 66mm crank can be made into a 71mm crank by offset grinding the rod journals.

I was wondering if I could have a 1.8L crank ground down to a 2.0L crank. If the people doing the work can add a little weld to the outside of the journals you should be able to.

I have TWO 1.8L cranks (paperweights) on my shelf.

No need to add material. The new journal has a smaller diameter and will have an axis further away from the crank centerline for the longer stroke.

I personally wouldn't do this, to do it right it would need to be rough cut, stress relieved, green ground, heat treated and final ground to size. I may have missed some steps, one may be re-drilling oil holes for the rods.

If you add the work costs up it's way cheaper to find the correct core in the first place.

[aggiezig]

Companies like DPR are doing exactly that

http://dprmachine.com/products/crankshafts-type-iv/

[gothspeed]

A 66mm crank can be made into a 71mm crank by offset grinding the rod journals.

I was wondering if I could have a 1.8L crank ground down to a 2.0L crank. If the people doing the work can add a little weld to the outside of the journals you should be able to.

I have TWO 1.8L cranks (paperweights) on my shelf.

No need to add material. The new journal has a smaller diameter and will have an axis further away from the crank centerline for the longer stroke.

(IMG:style_emoticons/default/agree.gif) Need to confirm but I believe that is what the factory did to achieve the 71 mm 2.0 stroke. Used the same forging then shaved additional material off the inside of the rod journals. This made the 2.0 crank journals a tad smaller diameter.

[Mark Henry]

Companies like DPR are doing exactly that

http://dprmachine.com/products/crankshafts-type-iv/

My crank is a welded Raby/DPR 78.4mm with type 1 rod journals.

Back several years ago Jake stopped using DPR due to quality issues, mostly because they used some in his mind questionable cores.
The core you send in to them will not be the same core you get back.

Would I still use them over a new china crank? Likely, but I'd carefully inspect the crank or pay a shop to do this.

[Mueller]

This might help, or it might confuse (IMG:style_emoticons/default/wink.gif)

[Mark Henry]

So that's ballpark .175" off of one side, I guarantee you are through the heat treating.
996 cranks don't even have enough heat treating to cut them 1st under.

In layman's terms the crank journal heat treat could be described as an eggshell. Very hard surface but softer underneath.

[gothspeed]

It is my understanding that cranks can be stress relieved and re-heat treated. Such as is done when crank journals are cut for undersize bearings.

This might help, or it might confuse (IMG:style_emoticons/default/wink.gif)

(IMG:style_emoticons/default/agree.gif)

[wndsrfr]

Gotta add my experience with 80mm cranks on my 2316 before I went with the FAT new forging one. Two failures....probably attributable to poor quality control in buildup welding and also the stress cracks from oil holes ending up too close to the web.
here's the links:
http://www.914world.com/bbs2/index.php?sho...=162641&hl=
http://www.914world.com/bbs2/index.php?sho...=197901&hl=

[Mark Henry]

Gotta add my experience with 80mm cranks on my 2316 before I went with the FAT new forging one. Two failures....probably attributable to poor quality control in buildup welding and also the stress cracks from oil holes ending up too close to the web.
here's the links:
http://www.914world.com/bbs2/index.php?sho...=162641&hl=
http://www.914world.com/bbs2/index.php?sho...=197901&hl=

I have a 78mm here that's a paperweight. I don't know who did the crank.

I also have a 996 paperweight.
Be thankful you're not having that bad luck with a 996, around $1500 for a good used crank. About $30k for a new engine.
I can do them cheaper with a shortblock from Porsche, but still bloody expensive.
M96/97 engines are keeping me busy.