Eagle 4340 Forged cranks
02-07-2010, 06:48 AM
#1
Eagle 4340 Forged cranks Has anyone run into issues with these? I know guys are snapping the cast ones, but what about the forged? I'd hope that their durability issues are limited to the cast as they have the perfect forged crank that I've been looking for (It's the right price...~$700), now it's just a matter of cash.....that I'll hopefully have soon.....
02-07-2010, 07:07 AM
#4
On the forged you just need to have the machining carefully double checked. For $700 though I would be looking at something more like Compstar.
Any additional machining the Eagle will need and the substantial likelihood it will be hard to balance mean in actual use Eagle is NOT the least expensive route to take.
Any additional machining the Eagle will need and the substantial likelihood it will be hard to balance mean in actual use Eagle is NOT the least expensive route to take.
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02-07-2010, 10:15 AM
#8
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im making a little over 800 hp at the crank...a guestament...
i have a 4340 eagle crank and h deam rods. and running a 300 shot. 9.51 1/4 mile 6.01 1/8 mile i think its a decent product for a 800 hp motor. but if you can get a lunati for 600 i say do it...
i have a 4340 eagle crank and h deam rods. and running a 300 shot. 9.51 1/4 mile 6.01 1/8 mile i think its a decent product for a 800 hp motor. but if you can get a lunati for 600 i say do it...
02-07-2010, 10:28 AM
#9
I saw the 4.0 stroke 4340 eagle for sale really cheap a while back,there was a place on ebay that was selling them for 300.I was pretty close to getting it,I thought it would be fun to build a 408.Are you the one that was wanting to do this I saw in a post recently?I think I saw one in the classifieds on here not to long ago.Search for it.I think the 4340 cranks are ok. cast no way
02-07-2010, 11:22 AM
#11
Eagle's reputation has been a bit tarnished with the explosion of instances of failures of their cast cranks (seen first-hand). While I am sure their forged pieces are more likely to withstand the abuse of their cast counterparts, I would not recommend them - just my opinion. Look elsewhere.
02-07-2010, 01:15 PM
#12
The sledgehammer is an import forging just like most of them, and will need the same look over that should be done regardless of brand. At that price though, it is quite a bargain.
It is not the horsepower rating you should be looking at - most of the forged cranks are good to four digit horsepower numbers that 99% of us will never reach. You need to be willing to spend the extra for a proper checking and machining.
The eagle usually takes more in machining costs then a higher end crank like compstar, but regardless of the brand you need to have it machined and balanced with your parts.
It is not the horsepower rating you should be looking at - most of the forged cranks are good to four digit horsepower numbers that 99% of us will never reach. You need to be willing to spend the extra for a proper checking and machining.
The eagle usually takes more in machining costs then a higher end crank like compstar, but regardless of the brand you need to have it machined and balanced with your parts.
02-07-2010, 03:09 PM
#15
Eagle cranks are US made from imported forgings.
This keeps the price down but maintains better quality then a pure overseas crank, and many maufacturers follow this same path.
Like mentioned, as long as you go forged and have it machined and assembled properly you will be fine.
This keeps the price down but maintains better quality then a pure overseas crank, and many maufacturers follow this same path.
Like mentioned, as long as you go forged and have it machined and assembled properly you will be fine.
02-07-2010, 05:12 PM
#16
This is kinda what I figured. FWIW this crank will not be thrown into the block without a real close inspection and a bit of work. Yea I'm the guy looking to build a 408. K1 told me about $750 for a 4" stroke crank and Scat told me for a 40lb light weight version it would be about $1200 and for a billet light weight version it was just shy of $2K. I'm thinking I'll just go with the Eagle.....get it checked and worked and then just keep it under 7K RPM and it should live a long, not-so-peaceful life under a Magnuson charger.
02-08-2010, 09:55 AM
#20
This is kinda what I figured. FWIW this crank will not be thrown into the block without a real close inspection and a bit of work. Yea I'm the guy looking to build a 408. K1 told me about $750 for a 4" stroke crank and Scat told me for a 40lb light weight version it would be about $1200 and for a billet light weight version it was just shy of $2K. I'm thinking I'll just go with the Eagle.....get it checked and worked and then just keep it under 7K RPM and it should live a long, not-so-peaceful life under a Magnuson charger.
. I wouldn't put much nitrous or boost to that short of a piston, and that close to the water jackets, but its sure to be one NASTY setup if you do 
. I hope you are doing a half fill for cheap insurance.I SERIOUSLY considered selling my 0 miles fully forged/half filled 383 and going with a 408 since I will only be NA and my shortblock was built for big hits of nitrous so will be overkill for my all motor HR setup that probably won't break 600 flywheel.
Lack of patience, less funding then when I started, and the crappy market for selling made me decide to just keep it, at least for now.
Either way your project will be an epic build to follow, and a learning experience whether it works out or not
.