Eagle Forged cranks are BACK! Great deals!

[kidglok]

Might be out of line but how could you know so much about metallurgy and not spell "steel" and "tensile" correctly?

From the research ive gathered ttype6 is correct in his statements about 4140 vs 4340. As well as the fact that the older eagle cranks were in fact 4340, this apparently is the first run of 4140 buick cranks by them, which, raises the question of what power level they can safely handle. Eagle says 1000hp, their website says 1500hp, how they came up with either number is beyond me because they have never been run in a performance engine to date.

 

[chopped39]

I went through this years ago when My friends dad made me steel caps for my engine. The price in the steel was what I asked about because there was a difference . I remember him saying something about the nickle content but he said its more brittle and its harder to work with which is why Eagle is probably using 4140. the strength was real close he said because of the hardening process.Im going to ask the metallurgist at work and see what they say about it.

 

[haywire4130]

How did I not notice the spell check? If I can't spell those two words,everything I think I know must be wrong. What part of what I wrote is incorrect?

To my knowledge, nothing but the spelling was incorrect.

 

[dr_frankenstein]

okay... so its a slightly lower grade.

who has seen a 4140 crank fail? ive bought plenty of SBC 4140s and never lost one.... hell got away for years in a blown BBC on a 5140 crank.

I would be plenty happy spending 500 on a 4140 crank that will almost promise to outlive any 109 block. hell i bet this 4140 stick will be just fine in my stage along with my other "no no" window maker connecting rods.

Sometimes I think we as buick people get obsessed with the fact it has to be super friggin batman awesome just to run 10s or 9s. what were looking at 125K psi for 4140 and 145K psi for 4340? Average 4140 cranks holding 1000 and 4340 holding 1500? while our stock pos is rated at what..... 85K psi? sounds like a fine upgrade to me.

So lets not bitch and enjoy 500 dollar forged cranks.

 

[Sydwyndr]

4140 is the brittle one. That's why it is prone to cracking. When you try to pull 4140 apart it cracks because of its inability to stretch or flex.This is the same problem you have with a stock crank.

Because of this,the list of applications for 4140,in the Earle M. Jorgensen Company's alloy reference book doesn't include crankshafts. Here is what they have to say about 4340.

4340
Nickel-Chromium-Molybdenum Steel

This is the “king” of the hardening grades of constructional alloy steels. Because
of richer alloy content, 4340 possesses much deeper harden ability than the 4100
series. This advantage is realized principally where high strength is required in
heavy sections. In addition, unusually high harden ability insures maximum toughness
and ductility at the desired strength level. The fatigue-tensile ratio makes this grade
ideal for highly stressed parts. It maintains its strength, ductility, and toughness
at relatively high temperatures. It has remarkable non-distorting properties for an
alloy steel. Thus, for high strength in heavy sections, or for highly stressed parts
operating under the most severe conditions, or where the greatest margin of safety
is desired, this is the steel to use.

Here is there list of applications.

APPLICATIONS – Automotive and marine crank shafts, diesel engine crank shafts
and other heavy-duty shafting, axle shafts, dies, subs, gear shafts, gears,
mine-drilling parts, oil-well fishing tools, perforating gun bodies, master hobs, etc.

Hey if you want to have this discussion take it elsewhere, this is a Advertisers thread and Mike is simply telling you what he has in stock. He doesn't have to defend anything at all. These cranks have been out and Mike simply stated how much power they can handle. Take this somewhere else because this particular thread isn't the place. Start one in the lounge if you like.

 

[turbobitt]

I guess I'll get sucked in since I have experience in this field.....
The Chinese cranks are most likely made from locally procured material. This keeps the cost down since shipping US steel would not make the cranks competative. There material of choice for 4140 equivalent is 42CrMo and hase a lot of overlap to 4140 specs and regarded as an equivalent. The material strength is not only the ingredients but also the impurities. Carbide stringers and slag can end any cranks race day really quick. This could happen with our own material here in the states. Now to control material cleanliness we can specify E4140 with "E" being electromelt material. This material is far cleaner and results I'm a much stronger and predictable performing steel. As far as I know I don't think that is controlled or available with Chinese spec steel.
AG.


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[forcefed3.8's]

I believe the bms cranks were 4140.

 

[Ttype6]

Advertisers thread and Mike is simply telling you what he has in stock.

The one thing he didn't do was tell us what he has. Now we know and will be able to make a better informed decision. It costs less for a reason.

 

[BEATAV8]

The cranks that Eagle used to sell were 4340. Was there someone else who sold 4140 cranks?

This contradicts Mike's post. He says these have always been 4140.

 

[Richard Miller]

Hopefully Mike still responds after all this debate over 4140 & 4340.
At least he is being honest and selling them as the 4140 material and not 4340.
Are the stroker cranks you have available wide or narrow journal?
I am looking for a wide journal stroker crank for a 109 block.
I am not sure if there is any vendor that has the wide journal stroker crank available?

 

[Mike Licht]

I really dont wish to do ths here but will be happy to discuss with anyone. I am telling you simply this. The only way we are going to know is too send both out for testing which frankly I am not doing, I know what I know from the folks who make/import these items and from experience. The Eagle cranks are rated for 1000HP, they have a GREAT history of not breaking and not being machined wrong, as mentioned above the BMS units were 4140 too, This is a great deal on a quality product that is finish machined in the US by a reputable company, and a good deal to boot. If you want the other crank, no problem, call and we will get you one of those. If you are going to put either one in a 109 or 4.1 block the block is what you should worry about, not the crank.

 

[Mike Licht]

Hopefully Mike still responds after all this debate over 4140 & 4340.
At least he is being honest and selling them as the 4140 material and not 4340.
Are the stroker cranks you have available wide or narrow journal?
I am looking for a wide journal stroker crank for a 109 block.
I am not sure if there is any vendor that has the wide journal stroker crank available?

currently there s no wide journal crank except for a custom billet, there is also no rod options at affordable prices. The current narrow journal crank and Molnar rod combo has reliably gone faster than a 109 block will go. I really dont see anyone doing it for that reason. My 4.1 will bust the block long beofre anything in it will fail I am sure of that. These crank rod combos have lots of history and a good track record

 

[Nick Micale]

Hey if you want to have this discussion take it elsewhere, this is a Advertisers thread and Mike is simply telling you what he has in stock. He doesn't have to defend anything at all. These cranks have been out and Mike simply stated how much power they can handle. Take this somewhere else because this particular thread isn't the place. Start one in the lounge if you like.

Ttype6 I would like you to take Clint's advise and take this to the Lounge as there has been conflicting information posted here, and it should be discussed in a general area where many others can see the information and make their own decision.

We have been aware of the "new" Eagle coming cranks for a few months, and it pissed me off that they "cheaped" out on 4140, or someone in China screwed up?

How can Eagle make a statement for years their crank is good for 1000 HP, but not lesser grade material is also good for 1000 HP?

 

[kidglok]

my last post here out of respect to mike and the moderators.

Unless this is not the BMS crank being discussed above:

 

[David Husek]

I believe the bms cranks were 4140.

.... as mentioned above the BMS units were 4140 too.

Unless this is not the BMS crank being discussed above:

Buick Motor Sport (BMS) cranks were forged in 4140, 4340 and 5140 in the early years. There were many design changes made to these cranks. Each forging has a designation on it that will tell what material it is made of.

Examples of some real early forgings:

R57 – 4140
R75 – 4340
N78 - 5140

They went thru many changes and the last design of the cranks that BMS forged was 4340 only. These are what most of us have picked up used from the Indy programs. If anyone has a BMS crank and wants to know what they have, contact me, I have a list of of numbers.

Just some FYI to clear up any misconceptions about BMS cranks

 

[Richard Miller]

These are internal balance, an external balance version is possible later but not available at this time

Which crank is the better?
Internal or External balance?

 

[Mike Licht]

Which crank is the better?
Internal or External balance?

It depends on your HP goals and what your doing. Generally speaking, internal is preferred in the racing world, but you will need a different flexplate and balancer which ups the cost significantly. For a street car or a car that does not run real high RPM (6400+) and external is a good option, the stock crank is external and they hold up very well as we know, but they are getting pretty old now

 

[Mike Licht]

As my friend John Wilde said the Eagle has landed, this is the first pallet off the truck, they are shipping today, thanks for the orders we are overwhelmed by the response and very grateful

 

[Ttype6]

this is the first pallet off the truck,

Why is the number 4340 printed on those boxes?

 

[Mike Licht]

don't know only know what I posted. I assume they use the same boxes for all, a heavy duty printed box is expensive, I doubt they are going to print different ones.