2winscroll

http://www.billzilla.org/engcrank.htm

2winscroll

Don't assume that an eagle is better than OEM. They have oiling issues and I doubt the 100mm is any stronger than the stock 4g64 crank.

https://www.evolutionm.net/forums/ev...options-3.html

Also the non billet Manley forged cranks are horrible they break a lot even at 500-600 horsepower.

2winscroll

I would have to agree with IBM, billet or OEM.

https://www.evolutionm.net/forums/ev...on-billet.html

LetsGetThisDone

iTrader: (1)

You can certainly shot peen a crank.


On the subject of a new eagle needing polished, I would return a brand new crank if the surface wasn't acceptable. Because that it simply unacceptable.

2winscroll

Well that's why you don't build 800+ horsepower motors. You keep stating the obvious grasping for anything. Acceptable unacceptable all depends on your build. So what RA finish is acceptable for big power build?

They are usually fine for lesser builds but sometimes you need to do it anyway to obtain the correct clearances.

You can see in the pics the oil holes are horrible chamfer and the journal surface is not what I would use in a 800+ build and this is a billet Manley not an Eagle. You can also see the surface has been shoot peened.

Hopefully the OP is now informed enough to make a good decision and not listen to people who think very highly of their own opinion, but have never really built a high horsepower motor before.

RightSaid fred

That book must have been written by someone who's never been near a crank grinding machine and wouldn't have a clue.

You can't straighten a crank in a press. Not in real life anyway......only in cyberspace.

Polishing is normally done with a 400 grit tape.



Doing a job in real life and writing a book about how to do something are 2 completely different things.


If you'v ever seen first hand a crank that's broken, they normally start cracking at the radius of of one of the journals (machined surface). it gets bigger until it breaks. Shot peening is NOT for machined surfaces.


If you read that article again, it says that the stock cranks are nitrided.
That's incorrect of course, they're not nitrided, they're induction hardened. Induction hardening is quite thick, you can grind down to 0.75 mm undersize and still be OK.
Aftermarket cranks are usually nitrided, they're too soft otherwise, you'll get scoring on the journals when you pull it apart if it's not nitrided.

2winscroll

All big horsepower builds should be micro polished not 400 grit 1970's technology. My machinist knows how to do it right.

I'm not worried cuz you definitely are not doing any of my machine work!

RightSaid fred

I 've done cranks for about 5 years.
What do you do?


What does "micropolished" mean?

Explain please.


If you want references.......the machinists hang out at "speedtalk".



Here we go

http://speedtalk.com/forum/viewtopic.php?f=1&t=1620

http://speedtalk.com/forum/viewtopic.php?t=8143

http://www.enginebuildermag.com/2005...smooth-enough/
https://speedtalk.com/forum/viewtopic.php?f=32&t=40781


The pic of that crank, the finish is unacceptable.

2winscroll

There is a big difference in a production machine shop and a high performance machine shop. The fact that you don't know is proof enough of that.

Tape polish, micro polish etc. are essential to big horsepower builds. When your pushing 7-8 horsepower per cube.

Check out winberg cranks they are actually the only ones that come factory ready to run.

LetsGetThisDone

iTrader: (1)

That crank you posted pics of looks oxidized. Like someone cleaned the oil off of it and let it sit..

2winscroll

Git-er-done your signature says it all.
Stock block, bolt-ons, purchased exhaust system, tuned by someone other than yourself.

Yet your telling folks how to build high horsepower motors, tune 2150 injectors, etc.

Really? You try to tell me I'm wrong on just about every post, but my car idled just fine on 2150's with the mods I was recommending. "Nope" you said it doesn't work but you've never even tuned them. Now you expect people to listen to your banter about crankshafts and you have never even built your own? You really need to get a grip on reality.
Ok here's my resume, I build motors for all different kinds of cars, I fabricate all my own headers, exhaust systems and charge piping, roll cages too. I've tuned only four evo's but they are all above yours in horsepower. Been tuning cars since Holley's were a big deal.
Personally I wouldn't let you rebuild my kids go cart motor.

LetsGetThisDone

iTrader: (1)

Yes, my car is the only one I work on.


You have no idea what I've built, what I've worked on, who I've worked on stuff with, etc. Trophy trucks, class 1 cars, a class 10 car, my offroad truck (built ford ranger), among other things. Hell, I've even built a 4g63 or two. Currently building another one. I may not do it as a primary source of income, but I'm certainly more capable than what you're presuming here.


As for the 2150's idle thing. You're about the only the person I've ever heard say that they don't have a somewhat unstable idle with stock motor/cam Evo, especially a X. To say they idle perfect is a stretch. They can idle pretty good though. And in the particular thread you're talking about, I assumed the guy was overstating just how "bad" the idle was. I've gotten in peoples cars that are having "INSANE OMG IT'S GONNA BLOW RIGHT NOW" drivability issues, when in reality it's a slight hiccup...lol