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Topic: crank failure - update with pictures (Read 1078 times)
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d55dave
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So I left work today, pulled onto the highway and went through first, second and third to 6 grand. The best stress releif there is when leaving work! When I came to stop and go traffic I noticed a very heavy vibration in the engine accompanied by a growling noise. When I pulled over and looked the crank pulley was wobbling around. After taking off the belts I noticed the pulley, dampner and forward part of the crank are all loose. I suspect the crank fractured just behind the timing gear. It is an Eagle 4" cast stroker crank (408). I will let you all know more when I pull the timing cover, etc. Has anyone heard of this before?
What a bummer!
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NYrr496
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I've broken the balancer hub on a 440 and seen broken cranks in stroker marine engines. Anything and everything is possible.
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Logged
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It takes a Mopar to catch a Mopar.
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west
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bummer.maybe its just the bearing  |
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67dartgt
Full Member
 Offline
Posts: 359
BigBlockDart.Com
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"heavy vibration followed by a growling noise..." Yup. I had that happen. Sounded just like that when I broke the crank in my 318. Although, I only got to run it for another 10 minutes trying to figure out what was wrong with it before the engine stuck.
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Think3205
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damn that's no good! i have that crank too! let me know how it turns out,hopefully it's not as bad as you think...
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440Ken
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Sounds like what happened to me many years ago. At the time I had the original 318 in the Swinger. Cruising down the highway at 70mph a bad vabration starts...pull off to the side and open the hood and the crack pulley is wobbling. Turn off engine and the pullies, balancer and about three inches of the crankshaft fall to the ground......all still bolted together.
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Logged
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Former "God Member" with 1180 posts
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chryco
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I`ve heard of and seen that too , only this was a factory forged crank on a 318 . The guy that had it was revvin' the bag of the thing , wasn`t too surprising . Chryco  |
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Logged
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Hemi Darts Rule !!!!!
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d55dave
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I pulled off the timing cover tonight. The break in the crankshaft is just behind the front main bearing. I can feel it with my finger but cannot see it yet. This weekend I will pull the engine and take the crank out to inspect the damage. I emailed Eagle and they say they have had no repeated problems with this crank but want me to give them a call tomorrow. I will keep you posted.
David
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Adam
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Sorry to hear about your little hiccup, Dave...git 'er back on the road ASAP   |
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Logged
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Eight cylinders all mine, all right, hold tight, I'm a highway star!
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west
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Sorry to hear about your little hiccup, Dave...git 'er back on the road ASAP if a broken crank is just a hicup I'd hate to see what a real problem is. |
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19swinger70
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i think the only thing after a broken crank is a nice picture window in the block. my condolences for your crank.
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d55dave
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Had I kept it runninrg I have no doubt it would have been catastrophic. If I am lucky I can get away with just bearings and a crank, timing set and gaskets...... wil have to wait and see. due to the way it broke it was still driving the timing chain, no valve to piston damage I hope.
I spoke to Eagle today and they thougth I was pushing the limits of the crank, they said the cast 408 crank is good to about 500 horse. I figured I am somewhere between 400 and 450. They say they will not leave me hung out to dry when it comes to warranty - I am hoping they credit me some value towards a forged crank.
David
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Adam
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Sorry to hear about your little hiccup, Dave...git 'er back on the road ASAP if a broken crank is just a hicup I'd hate to see what a real problem is. Just trying to stay positive. Good luck! I hope they don't screw with you on the warranty either. -Adam |
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Logged
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Eight cylinders all mine, all right, hold tight, I'm a highway star!
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73swinger
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holy cow man, BTW in the "broken crank 2" pic, the dark area isnt a new fracture, it's been arounf for awhile
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Logged
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nothingbutdarts
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Glad the block is OK! I sure hope they help you out financially with a new crank!
Definate BUMMER though
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Logged
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69 Swinger 340
Soon to be 69 426 Dart
80 Crew Cab gas hawg
01 DIESEL Hauler
Bailey, Colorado
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oldkimmer
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.........WOW...Ive only seen that in chevies..... yes, my own...b 4 I seen the light.......kim........
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Logged
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MR. Mechanic...........Panther Pink Duster The Beast has been Unleashed!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
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farmington
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If eagle doesn't do right by you go and see a metalurgist to have him determine why it broke and then go back at eagle.
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Logged
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When in doubt, Whip it out!
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Dono
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holy cow man, BTW in the "broken crank 2" pic, the dark area isnt a new fracture, it's been arounf for awhile
I am with you on that too. It looks as if the crack was there about half way. |
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Logged
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magart
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I had a Freightliner with a 500hp Detroit in it that did that-only at the rear. There was no noise, no miss, or anything-just a pulsation in the clutch pedal much like you'd get on the brake pedal with a bent rotor. We took the trans out thinking the center came out of the clutch, and once the clutch was off, the flywheel nearly fell on me. It was kinda strange to see that.
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Logged
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Beer in one hand, wrenches in the other.
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NYrr496
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holy cow man, BTW in the "broken crank 2" pic, the dark area isnt a new fracture, it's been arounf for awhile
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Logged
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It takes a Mopar to catch a Mopar.
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ValiantOne
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Ive never seen a crank failure, although I hear about the weak point being that fillet area. It looks like this one runs straight through the fillet. In the experience of the board is this the common breakage point?
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Logged
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Chris Evrard -76 Cordoba, 360 4bbl -68 Valiant, 273 2bbl -73 Dart, /6 1bbl, Leaning Tower of Power!!!  |
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NYrr496
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Ive never seen a crank failure, although I hear about the weak point being that fillet area. It looks like this one runs straight through the fillet. In the experience of the board is this the common breakage point?
I've seen that exact same failure a few times. |
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Logged
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It takes a Mopar to catch a Mopar.
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wrflyer
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I have seen it many times especially at the front main. The weird thing is the bearings usually look like new.
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Ryan (Strange246)
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Wasnt it Mopar Muscle that built a stroker 408 a couple years ago using an Eagle Crank and rods and the thing grenaded on the Dyno?
Ryan
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illfish
Guest
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It almost looks like there was a temperature change when they did the casting. That fault line seems to be an internal defect. The burnished metal is where the pieces were scuffing and the dull is where the final crack occured. I would bet that the burnished side of the crack was there for a while. The lightening hole also has a witness mark through it that looks like a casting flaw/temp change.
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Logged
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B-onefan
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Any Update's on this?
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Logged
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1999 Ram 1500 Sport QC 4X4
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flyboy01
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It almost looks like there was a temperature change when they did the casting. That fault line seems to be an internal defect. The burnished metal is where the pieces were scuffing and the dull is where the final crack occured. I would bet that the burnished side of the crack was there for a while. The lightening hole also has a witness mark through it that looks like a casting flaw/temp change.
Thats exactly what I was thinking. The flaw was probably there since new. |
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moparteacher
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Not pointing a finger, but over-tightened belts are known to break off cranks.
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Moparteacher
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broken crank 001.jpg
