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Another Eagle cast crank broken (408 stroker)
#634657
03/09/10 07:30 AM
03/09/10 07:30 AM
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Joined: Jan 2004
Posts: 143
Buenos Aires, ARGENTINA
madmax2
OP
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OP
member
Joined: Jan 2004
Posts: 143
Buenos Aires, ARGENTINA
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Last edited by madmax2; 03/09/10 10:16 AM.
'70 Dodge GTX sb 418ci (Early A-body),
Lunati Solid cam 270°/243°@.050/.548", Edelbrock Heads, Weiand X-CELerator,
Holley Terminator EFI, Tremec 6 sp manual, 3.90:1, TTI Headers.
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Re: Another Eagle cast crank broken (408 stroker)
[Re: madmax2]
#634658
03/09/10 10:07 AM
03/09/10 10:07 AM
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Joined: Jan 2003
Posts: 9,982
Ansonia, CT
CJK440
master
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master
Joined: Jan 2003
Posts: 9,982
Ansonia, CT
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Thats the second one i saw that broke the snout. After examining the one I had, I thought the weak point was the rear arm/journal cross section especially with all 8 cylinders twisting it.
2017 Contusion Blue Challenger T/A 392 M6 "BLKNBLU"
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Re: Another Eagle cast crank broken (408 stroker)
[Re: madmax2]
#634659
03/09/10 10:11 AM
03/09/10 10:11 AM
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Anonymous
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Anonymous
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that's not unusual with a cast crank. they just aren't made to hold up to that much horsepower.
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Re: Another Eagle cast crank broken (408 stroker)
[Re: SLOW67]
#634663
03/09/10 12:32 PM
03/09/10 12:32 PM
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Joined: Dec 2007
Posts: 830
east coast
Otherlane
super stock
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super stock
Joined: Dec 2007
Posts: 830
east coast
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Dram,tell me something new.Why does a stock 360 crank hold 450 hp and not this cast crank?I have never a stock crank breaking but I could be wrong.back to the topic I had one of the cast when they first came out and my block let go before the crank did.After twisting 2 h-beams the crank was still good.i was running 10.50@3400 pound car.if I was building a few motor I would do the steel crank.
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Re: Another Eagle cast crank broken (408 stroker)
[Re: Thumperdart]
#634665
03/09/10 01:14 PM
03/09/10 01:14 PM
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Joined: Jan 2004
Posts: 143
Buenos Aires, ARGENTINA
madmax2
OP
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OP
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Joined: Jan 2004
Posts: 143
Buenos Aires, ARGENTINA
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I not find reason why the eagle cast cranks (mopar , chevy, etc) are broken in the same place.  The car are a 3550 lb A-body.
'70 Dodge GTX sb 418ci (Early A-body),
Lunati Solid cam 270°/243°@.050/.548", Edelbrock Heads, Weiand X-CELerator,
Holley Terminator EFI, Tremec 6 sp manual, 3.90:1, TTI Headers.
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Re: Another Eagle cast crank broken (408 stroker)
[Re: emarine01]
#634668
03/09/10 01:52 PM
03/09/10 01:52 PM
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Joined: Feb 2003
Posts: 12,675
Columbia, CT
moper
I Live Here
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I Live Here
Joined: Feb 2003
Posts: 12,675
Columbia, CT
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Internal balance or external? As was asked.. what balancer and how did it go on?
Well, art is art, isn't it? Still, on the other hand, water is water! And east is east and west is west and if you take cranberries and stew them like applesauce they taste much more like prunes than rhubarb does. Now, uh... Now you tell me what you know.
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Re: Another Eagle cast crank broken (408 stroker)
[Re: moper]
#634669
03/09/10 02:00 PM
03/09/10 02:00 PM
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Joined: Jan 2004
Posts: 143
Buenos Aires, ARGENTINA
madmax2
OP
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OP
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Joined: Jan 2004
Posts: 143
Buenos Aires, ARGENTINA
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Quote:
Internal balance or external? As was asked.. what balancer and how did it go on?
is the engine of a buddy, the damper it's a Mopar Performance. 
'70 Dodge GTX sb 418ci (Early A-body),
Lunati Solid cam 270°/243°@.050/.548", Edelbrock Heads, Weiand X-CELerator,
Holley Terminator EFI, Tremec 6 sp manual, 3.90:1, TTI Headers.
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Re: Another Eagle cast crank broken (408 stroker)
[Re: madmax2]
#634670
03/09/10 02:06 PM
03/09/10 02:06 PM
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Joined: Feb 2003
Posts: 12,675
Columbia, CT
moper
I Live Here
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I Live Here
Joined: Feb 2003
Posts: 12,675
Columbia, CT
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Just me tossing out ideas here... This isnt the first I've seen in terms of web stuff of that particular break. I have a couple of these in service in the 460-480 level (and automatics) and I will admit I'm nervous enough to probably stop sourcing them. But it terms of the "whys"... It looks like it started at the fillet which "should" be a fairly strong area. But that's where the otrsional stress is and the rpm doesnt matter if the harmonis are bad for wahtever reason. External balancing lends itself to stressing the crank more forcing it to flex, and a loose balancer or one that was hammered on or honed to fit more loosely can all contribute to crank stress, as can detonation. Never mind the 4sp part.
Well, art is art, isn't it? Still, on the other hand, water is water! And east is east and west is west and if you take cranberries and stew them like applesauce they taste much more like prunes than rhubarb does. Now, uh... Now you tell me what you know.
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Re: Another Eagle cast crank broken (408 stroker)
[Re: Otherlane]
#634672
03/09/10 02:33 PM
03/09/10 02:33 PM
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Anonymous
Unregistered
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Anonymous
Unregistered
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Quote:
Dram,tell me something new.Why does a stock 360 crank hold 450 hp and not this cast crank?I have never a stock crank breaking but I could be wrong.back to the topic I had one of the cast when they first came out and my block let go before the crank did.After twisting 2 h-beams the crank was still good.i was running [Email]10.50@3400[/Email] pound car.if I was building a few motor I would do the steel crank.
i don't have a definitive answer for you. i've seen plenty of broken cast cranks over my 34+ years in this business. there are a lot of places the blame could be placed, so take your pic.
bad cranks/ castings
bad balance job, internal vs. external
bad damper
heavy bobweights
and the list goes on and on.
some cranks seem to survive, others don't.
i do recommend moving up to a forged crank when your plans exceed 450 hp. that 450 hp might be fine, but what happens when you start making other improvements and then your at 500, or 550 or even more. plan ahead. it's cheaper in the long run to buy the better crankshaft up front IMO unless it's just going to be a slightly warmed over stock type build. i understand about working within a budget, but you don't ask for temporary fillings (i.e. cheaper) when you go to the dentist, so don't ask for a temporary crankshaft when you build your bracket motor.
Last edited by DRAM_Perf_Only; 03/09/10 02:34 PM.
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Re: Another Eagle cast crank broken (408 stroker)
#634673
03/09/10 02:37 PM
03/09/10 02:37 PM
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Joined: Mar 2003
Posts: 2,495
PA
moparacer
top fuel
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top fuel
Joined: Mar 2003
Posts: 2,495
PA
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Exact same failure I had except mine broke at the back.
Just too thin between the rod and main journals.
67 Barracuda street/bracket car 11.27-119
68 Dart 502 BB 8.70s-152
414 cid SB Dragster 7.65-174
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Re: Another Eagle cast crank broken (408 stroker)
[Re: Otherlane]
#634674
03/09/10 08:38 PM
03/09/10 08:38 PM
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Joined: Aug 2005
Posts: 637
Sao Paulo, Brazil
dart_73_br
mopar
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mopar
Joined: Aug 2005
Posts: 637
Sao Paulo, Brazil
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Quote:
Dram,tell me something new.Why does a stock 360 crank hold 450 hp and not this cast crank?
Because old stock cranks was not made in China! 
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Re: Another Eagle cast crank broken (408 stroker)
[Re: dart_73_br]
#634676
03/09/10 08:52 PM
03/09/10 08:52 PM
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Joined: Jun 2003
Posts: 52,972
Romeo MI
MR_P_BODY
Master
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Master
Joined: Jun 2003
Posts: 52,972
Romeo MI
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JMO but I would believe that it was a balance issue, got it balanced from the company and in a lot of cases thats not even close.... again JMO without knowing facts 
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