Which Steel Crank???

007gn

Active Member
my question is which steel crank to buy . Internal or external balance ? Eagle or gn1. And also do I keep it stock stroke or go with a stroker kit . This would be for a 4.1 block . Fully ported gn1 heads 6870 turbo 215/220 hyd roller cam . & also Do the stroker set ups still rev as quick as the stock stroke motors . I'm asking bcoz I gotta replace my crank & im trying to figure which direction to go . Thanks for all your help guys.
 

TURBOELKY

Well-Known Member
where are you located. Picking the right crank is as important as who you have machine and assemble your setup. Arizona GN has the best cranks around, and if you're in the Los Angeles area, turbolou is the guy to see.
 

007gn

Active Member
where are you located. Picking the right crank is as important as who you have machine and assemble your setup. Arizona GN has the best cranks around, and if you're in the Los Angeles area, turbolou is the guy to see.[/QUOT thanks for the reply & I'm in Detroit . I'll see what Arizona GN has to offer . I'm close to full throttle . But again what are the differences between the cranks pros n cons.
 

fastblackracing

Well-Known Member
Investing the money neccessary to build a nice forged rotating assembly it only makes sense to go with the better internally balanced assembly for a few more $$.

I would never spend almost the same money and retain the external balanced strategy.

And I would also go with the extra cubic inches the strroker gives as it makes the car more responsive off boost, and will help with getting a bigger turbo up on boost.

Overall maximum power is dictated by your turbos airflow limitation and a bigger engine may not make much more peak power than a smaller engine with the same turbo maxed out since the turbo will be the limiting factor.

But my experience is the bigger cubic inch engines in general do everything better and easier and make for a more enjoyable car to drive.
 

Toby_Goodmk

Test Fit officianto
I have a stroked Husek internal balanced assembly machined assembled and balanced by Zimmerman. I'll tell you this...it is so smooth at times I need to look at the rpms at off throttle cruise to see if the car is still running. And, at idle, engine doesnt move in the cradle. Stroked, internal balanced is a winner in my situation.
 

TurboBuRick

Moderator
Staff member
All the cranks come from tha same place. China. There are 2 different grades of steel. 4340 and 4130. 4340 is the better material.
All the new steel cranks are internal balanced.
 

TURBOELKY

Well-Known Member
All the cranks come from tha same place. China. There are 2 different grades of steel. 4340 and 4130. 4340 is the better material.
All the new steel cranks are internal balanced.
This is true but there are two know variances I know of. One has a proper machined rear main seal journal, slightly oversized to keep it from leaking. The other has the Archimedes swirl on it, it's factory spec, and will leak like a factory crank. I know AZGN has the good crank.
 

TurboBuRick

Moderator
Staff member
The eagle cranks are 4130. Look it up. Neoprene seal can still be used on the knurled cranks. It's been done a million times with good results.
 

TURBOELKY

Well-Known Member
The eagle cranks are 4130. Look it up. Neoprene seal can still be used on the knurled cranks. It's been done a million times with good results.
It's been done a million times because, that's all you can do lol. Reality is, any aftermarket crank is going to be better than stock, and likely out live the factory block anyways. (y)
 

TurboBuRick

Moderator
Staff member
Really? Ok..

image.jpeg
 

ek02

Well-Known Member
I have 2- 4.1's with stroker cranks. One has the knurled seal surface (Dave Husek) and the other has a smooth surface (CAT). Neither one leaks at the rear main with the seal offset 1/4" and The Right Stuff in the side grooves. You will need a set of custom pistons anyway for a 4" bore, so going with the stroker will cost the same as a stock stroke. Go with Molnar rods, which are made to clear the cam with a stroker crank, although rod to cam clearance must be checked to be sure. You will have to clearance the block at the oil passage for # 1 rod. The rod bolt hits the block there.
 

Nick Micale

Tech Advisor
Staff member
All the cranks come from tha same place. China. There are 2 different grades of steel. 4340 and 4130. 4340 is the better material.
All the new steel cranks are internal balanced.

I do not want to be an "ass" about this discussion, but our experience with using well over 200 China forged cranks, they vary a lot depending on where and how they are machined.

There may be only one place that does the forging, but I do know for sure they are finished machined in various places.

We have had Eagle make us 2 batches of external balanced cranks we used for stock replacement rebuilds. Same forging, just machined differently.

The machining varies depending on the supplier.

I have a couple forged China cranks I obtained to check out other sources, and they are now expensive "bookends" as the machine work is not up to our standards.

My opinion is if an owner is purchasing a forged crank, I would go with Eagle, the people there are great, and so are their products! :)
 
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