Bent crankshaft causes and myths
#1562297
01/12/14 06:28 PM
01/12/14 06:28 PM
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Joined: Dec 2004
Posts: 10,607 Rittman Ohio
fourgearsavoy
OP
I Live Here
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OP
I Live Here
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Posts: 10,607
Rittman Ohio
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Has anybody ever seen first-hand a crank bend from laying in a box on a shelf? Now to me it seems physically impossible that something that is built so strong can bend under it's own weight.Now if this were true how could you possibly ship one I'm building a Chevy small block for my father-in-laws Vette and one his "buddies" tried to tell me not to use the crank he has becuse it's bent because it's been laying on a shelf for too long. Now if this is true how long does it take for a crank to bend under it's own weight? One week, one hour, a year Now most of us have purchased a brand new crank and it comes in a box that has probably been on a shelf for a while so are they all bent? Gus
64 Plymouth Savoy 493 Indy EZ's by Nick at Compu-Flow 5-Speed Richmond faceplate Liberty box Dana 60
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Re: Bent crankshaft causes and myths
[Re: fourgearsavoy]
#1562300
01/12/14 07:40 PM
01/12/14 07:40 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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Quote:
Has anybody ever seen first-hand a crank bend from laying in a box on a shelf? Now to me it seems physically impossible that something that is built so strong can bend under it's own weight.Now if this were true how could you possibly ship one I'm building a Chevy small block for my father-in-laws Vette and one his "buddies" tried to tell me not to use the crank he has becuse it's bent because it's been laying on a shelf for too long. Now if this is true how long does it take for a crank to bend under it's own weight? One week, one hour, a year Now most of us have purchased a brand new crank and it comes in a box that has probably been on a shelf for a while so are they all bent? Gus
To me if they bend that easy you dont want it.. but most crank shops hang them from the back flange BUT thats to save space in the shop... the one shop I use to deal with I asked them this myth and thats all it was.. a myth unless you put a few hundred pounds on it for a LONG time... its easy enough to check with V-blocks or on the lathe
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Re: Bent crankshaft causes and myths
[Re: drew72]
#1562302
01/12/14 08:37 PM
01/12/14 08:37 PM
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Joined: Jan 2003
Posts: 15,589 Norwich CT USA
moparts
I Live Here
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I Live Here
Joined: Jan 2003
Posts: 15,589
Norwich CT USA
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Quote:
And batteries will discharge sitting on concrete.
But the old tar top batteries will ( Pre 70's ), not the plastic case ones
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Re: Bent crankshaft causes and myths
[Re: Cab_Burge]
#1562304
01/12/14 10:46 PM
01/12/14 10:46 PM
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Joined: Jun 2009
Posts: 171 Indy
moparman89
member
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member
Joined: Jun 2009
Posts: 171
Indy
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Cant believe this is even a thread. If a crank will bend under its own weigh how would it ever hold up to the stresses of a engine?
School of Automotive Machinists Racing
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Re: Bent crankshaft causes and myths
[Re: moparman89]
#1562305
01/12/14 10:49 PM
01/12/14 10:49 PM
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Joined: Oct 2011
Posts: 515 geezer acres rest home
dakotawilly
mopar
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mopar
Joined: Oct 2011
Posts: 515
geezer acres rest home
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Chinese cranks are a crapshoot,their idea of runout is when the cat gets away from the butcher block.plus I am quite sure the average employee at the bingdong crankshaft factory cant read.....hence the occasional blem sales from most of the crank distributors.....
Last edited by dakotawilly; 01/12/14 10:55 PM.
SFI 25.5 depends,no leak,even at 213 mph....
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Re: Bent crankshaft causes and myths
[Re: GTX MATT]
#1562308
01/13/14 05:16 PM
01/13/14 05:16 PM
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Joined: Aug 2004
Posts: 2,128 sweden
sshemi
top fuel
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top fuel
Joined: Aug 2004
Posts: 2,128
sweden
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This is stupid. If it gets bent when laying down it should get longer when hung and shorter when standing. Again its just stupid.
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Re: Bent crankshaft causes and myths
[Re: sshemi]
#1562310
01/13/14 07:22 PM
01/13/14 07:22 PM
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Joined: Dec 2009
Posts: 21,055 in a cattle trailer down by th...
Guitar Jones
Paddle faster! I hear banjo music!
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Paddle faster! I hear banjo music!
Joined: Dec 2009
Posts: 21,055
in a cattle trailer down by th...
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Quote:
This is stupid.
If it gets bent when laying down it should get longer when hung and shorter when standing. Again its just stupid.
Man I've been doing it wrong!
"Come get your wife"
'92 D250 Club Cab CTD, 47RH conversion, pump tweaks, injectors, rear disc and hydroboost conversion. '74 W200 Crew Cab 360, NV4500, D44, D60 and NP205 divorced transfer case. Front and rear disc and hydroboost conversion. 2019 1500 Long Horn Crew Cab 4WD, 5.7 Hemi.
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Re: Bent crankshaft causes and myths
[Re: cudaman1969]
#1562312
01/13/14 09:28 PM
01/13/14 09:28 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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Quote:
Not a crank but something along the same line are the propeller shaft in navy ships. Some are 200 feet long or more and 36-48 inches in diameter. When docked they turn them very slowly to keep from bending. If they have to work on any part of the shaft they put blocks every so many feet for support, they will bend if not done.If it bends it's remachined where it rides, quite a process since it can't be removed from ship
I've never seen one that long but the 1000' ships here shut down and nothing is turning... I never turned my shafts even over the winter on my barge
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Re: Bent crankshaft causes and myths
[Re: cudaman1969]
#1562314
01/13/14 10:11 PM
01/13/14 10:11 PM
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Joined: Oct 2011
Posts: 515 geezer acres rest home
dakotawilly
mopar
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mopar
Joined: Oct 2011
Posts: 515
geezer acres rest home
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I suppose anything could bend under the right conditions,how about the friendly delivery guy tossing it during shipping,you know the old saying,"hey yall watch this"................
SFI 25.5 depends,no leak,even at 213 mph....
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Re: Bent crankshaft causes and myths
[Re: fourgearsavoy]
#1562315
01/13/14 10:12 PM
01/13/14 10:12 PM
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Joined: Jul 2008
Posts: 30,632 Florida STAYcation
IcorkSOAK
Financed his waterbed
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Financed his waterbed
Joined: Jul 2008
Posts: 30,632
Florida STAYcation
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Quote:
Has anybody ever seen first-hand a crank bend from laying in a box on a shelf?
WITH the major weather TEMP CHANGES in Ohio ...I have heard a CRANKy person can get bent-outa-shape just thinking about the great tropical temps in Florida ....
What say YOU ?
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