Eagle crank claims another victim

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Ott

Ott

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The Eagle crank let go in my 408 stroker.

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Based on other threads, this is not an uncommon situation for Eagle cranks. Due to the lack of any obvious issues, and the fact that the engine shows very little wear, my mechanic thinks it was likely a casting flaw that's to blame. Time to order a forged crank.
 
Sorry to hear the bad news. I went with forged Scat Crank. Just got the short block done for my 408.
 
72Dart6pack said:
Sorry to hear the bad news. I went with forged Scat Crank. Just got the short block done for my 408.
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Thanks. I plan on going with a forged Scat. I'm waiting to see if I just need a crank or the entire rotating assembly. I had big plans for this summer, so with luck they'll be just delayed a little.
 
Looks like it has a counterbalance hole drilled into the end of the journal, likely for getting the balance better with the lighter cast material. It's an obvious spot for weakness.
 
Kevin D. said:
How hard were you spinning it?
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That's the strange part. I parked it last winter, everything A-OK. Got it out this spring and after driving it about 5 miles (drivng it like a grandma), I pressed in the clutch coming up to a stop and that's when it let loose.
 
I think any cast crank would work just fine(Except for Eagle!!!) but if i had this problem i would be going forged just for the piece of mind.
MAN you're lucky the crank didn't WINDOW your Block!
 
Kevin D. said:
Maybe a better question would have been how hard have you spun it?
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I've never, in my opinion, hammered the motor. I've done burnouts, etc. but hadn't yet made it to the track. However, I can't speak for the past owner(s).
 
How about a pix of the front end of the 1-2 journal, or the back end of the 7-8 journal? I am curious to see any hole there, if any.
 
Reminiscent of my cast eagle 408 crank. It was good for 500 horse they said. Worked great the first year in my Dart with the auto. Then I put the 4 speed in and the first time i powershiftef it hard into second somewhere north of 5 grand it started vibrating badly. It fractured the crank just ahead of the forward most counterweight, very similar to yours. Eagle creditted the cost of the cast crank toward tbeir forged one...... there wasn't too much other damage thankfully. The forged piece was much nicer.
 
Why not look at rod Bloomers steel crank very nice and cheaper then the scat BPE web site
 
nm9stheham said:
How about a pix of the front end of the 1-2 journal, or the back end of the 7-8 journal? I am curious to see any hole there, if any.
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so are you thinking the cranks integrity was compromised by the balancing ,because that seems like it makes sense by that photo
 
As the rod journal moves further off the crank center line, there's less material to hold the crank together. Easy to see why it breaks. Balancing may contribute to it, but it;s not the culprit. The long stroke on the cast crank is, IMO.
 
RustyRatRod said:
As the rod journal moves further off the crank center line, there's less material to hold the crank together. Easy to see why it breaks. Balancing may contribute to it, but it;s not the culprit. The long stroke on the cast crank is, IMO.
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ya I get that RRR, but that seems like a big hole in the end of that thing,I would not like that.
 
K.O. SWINGER said:
ya I get that RRR, but that seems like a big hole in the end of that thing,I would not like that.
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i don't either. I have seen a lot of them made that way though, so sometimes you have no choice.
 
I have been thinking scat 4" for my 340 sixpack next year nothing cazy ported procomps, 490 hp or so 4speed with 275/50/15 nittos...what do you think.should I worry about it strength for that set up
 
I would not run that eagle cast in anything but the mildest build. Like under 430hp. And NOT with a 4sp. Any other cast is fine. Just not the Eagle.
 
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