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Bent crankshaft causes and myths #1562297 01/12/14 06:28 PM 01/12/14 06:28 PM
Joined: Dec 2004 Posts: 10,551 Rittman Ohio fourgearsavoy OP I Live Here
fourgearsavoy OP I Live Here Joined: Dec 2004 Posts: 10,551 Rittman Ohio	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 7995091-savoyburnout.jpg (208 downloads) 64 Plymouth Savoy 493 Indy EZ's by Nick at Compu-Flow 5-Speed Richmond faceplate Liberty box Dana 60

Re: Bent crankshaft causes and myths [Re: fourgearsavoy] #1562298 01/12/14 07:34 PM 01/12/14 07:34 PM
Joined: Dec 2010 Posts: 1,035 Missouri U.S.A. 7 71yelladustr super stock
71yelladustr super stock 7 Joined: Dec 2010 Posts: 1,035 Missouri U.S.A.	Those guys probably believe in unicorns too. If you are concerned about it why not just check it? I would think if you installed only the #1 and #5 upper main bearings in the block, then layed the crank in the bearings, and slowly spun it with a dial indicator on the #3 main journal it would show any signs of a bend. Correct?? 392 gen III hemi on E-85 727 trans Dana 60 10.02@134

Re: Bent crankshaft causes and myths [Re: fourgearsavoy] #1562299 01/12/14 07:39 PM 01/12/14 07:39 PM
Joined: Jan 2003 Posts: 1,020 Andrews,In. U.S.of A. 6 67_Satellite super stock
67_Satellite super stock 6 Joined: Jan 2003 Posts: 1,020 Andrews,In. U.S.of A.	I'd rather let it lie flat for years than stand it on end and knock it over once.

Re: Bent crankshaft causes and myths [Re: fourgearsavoy] #1562300 01/12/14 07:40 PM 01/12/14 07:40 PM
Joined: Jun 2003 Posts: 52,972 Romeo MI MR_P_BODY Master
MR_P_BODY Master Joined: Jun 2003 Posts: 52,972 Romeo MI	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

Re: Bent crankshaft causes and myths [Re: MR_P_BODY] #1562301 01/12/14 08:26 PM 01/12/14 08:26 PM
Joined: Aug 2010 Posts: 343 S.E.Mich D drew72 enthusiast
drew72 enthusiast D Joined: Aug 2010 Posts: 343 S.E.Mich	And batteries will discharge sitting on concrete.

Re: Bent crankshaft causes and myths [Re: drew72] #1562302 01/12/14 08:37 PM 01/12/14 08:37 PM
Joined: Jan 2003 Posts: 15,547 Norwich CT USA moparts I Live Here
moparts I Live Here Joined: Jan 2003 Posts: 15,547 Norwich CT USA	Quote: And batteries will discharge sitting on concrete. But the old tar top batteries will ( Pre 70's ), not the plastic case ones

Re: Bent crankshaft causes and myths [Re: fourgearsavoy] #1562303 01/12/14 10:24 PM 01/12/14 10:24 PM
Joined: Aug 2003 Posts: 43,095 Bend,OR USA C Cab_Burge I Win
Cab_Burge I Win C Joined: Aug 2003 Posts: 43,095 Bend,OR USA	I've had several 318 forged steel cranks out of OEM production motors that had the #2 main bent(checking it with a set of V blocks and a dial indicator) .0007 that was just enough to make those cranks kave a tight spot when spinning it without any rods or pistons in the motor. I have heard the same thing on laying cranks down, they will bend Maybe a cast iron crank will I also have several smashed toes from bumping into a crank standing up and it falling forward onto my foot I have several new foregded steel stroker cranks in thier shipping boxes laying on my shelfs in the shop, I have never seen or heard of or had a forged steel crank be bent if it had not spun a rod bearing or suffered some other form of abuse first Mr.Cab Racing and winning with Mopars since 1964. (Old F--t, Huh)

Re: Bent crankshaft causes and myths [Re: Cab_Burge] #1562304 01/12/14 10:46 PM 01/12/14 10:46 PM
Joined: Jun 2009 Posts: 171 Indy M moparman89 member
moparman89 member M Joined: Jun 2009 Posts: 171 Indy	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

Re: Bent crankshaft causes and myths [Re: moparman89] #1562305 01/12/14 10:49 PM 01/12/14 10:49 PM
Joined: Oct 2011 Posts: 515 geezer acres rest home D dakotawilly mopar
dakotawilly mopar D Joined: Oct 2011 Posts: 515 geezer acres rest home	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....

Re: Bent crankshaft causes and myths [Re: dakotawilly] #1562306 01/13/14 04:59 AM 01/13/14 04:59 AM
Joined: May 2003 Posts: 6,558 Downtown Roebuck Ont Twostick Still wishing...
Twostick Still wishing... Joined: May 2003 Posts: 6,558 Downtown Roebuck Ont	Define bent. .00000x I'm sure could happen by putting it in a hot sunny window that only heated one side. If it was stored on its side and only supported by the end mains I'm sure there is also measurable deflection but I doubt there are many people with the instruments to accurately measure it. Kevin

Re: Bent crankshaft causes and myths [Re: dakotawilly] #1562307 01/13/14 05:56 AM 01/13/14 05:56 AM
Joined: Jun 2006 Posts: 5,159 CT GTX MATT master
GTX MATT master Joined: Jun 2006 Posts: 5,159 CT	Quote: 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..... Now I need to pin those needles, got to feel that heat Hear my motor screamin while I'm tearin up the street

Re: Bent crankshaft causes and myths [Re: GTX MATT] #1562308 01/13/14 05:16 PM 01/13/14 05:16 PM
Joined: Aug 2004 Posts: 2,128 sweden S sshemi top fuel
sshemi top fuel S Joined: Aug 2004 Posts: 2,128 sweden	This is stupid. If it gets bent when laying down it should get longer when hung and shorter when standing. Again its just stupid.

Re: Bent crankshaft causes and myths [Re: sshemi] #1562309 01/13/14 07:21 PM 01/13/14 07:21 PM
Joined: Jul 2008 Posts: 53 Sullivan, IN M Mopar Sam member
Mopar Sam member M Joined: Jul 2008 Posts: 53 Sullivan, IN	It lays flat in the motor.

Re: Bent crankshaft causes and myths [Re: sshemi] #1562310 01/13/14 07:22 PM 01/13/14 07:22 PM
Joined: Dec 2009 Posts: 20,622 in a cattle trailer down by th... G Guitar Jones Paddle faster! I hear banjo music!
Guitar Jones Paddle faster! I hear banjo music! G Joined: Dec 2009 Posts: 20,622 in a cattle trailer down by th...	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! "Follow me the wise man said, but he walked behind" '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. Rear disc and hydroboost coming soon! 2019 1500 Long Horn Crew Cab 4WD, 5.7 Hemi.

Re: Bent crankshaft causes and myths [Re: Guitar Jones] #1562311 01/13/14 09:17 PM 01/13/14 09:17 PM
Joined: Jan 2004 Posts: 8,233 fredericksburg,va C cudaman1969 master
cudaman1969 master C Joined: Jan 2004 Posts: 8,233 fredericksburg,va	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

Re: Bent crankshaft causes and myths [Re: cudaman1969] #1562312 01/13/14 09:28 PM 01/13/14 09:28 PM
Joined: Jun 2003 Posts: 52,972 Romeo MI MR_P_BODY Master
MR_P_BODY Master Joined: Jun 2003 Posts: 52,972 Romeo MI	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

Re: Bent crankshaft causes and myths [Re: MR_P_BODY] #1562313 01/13/14 09:57 PM 01/13/14 09:57 PM
Joined: Jan 2004 Posts: 8,233 fredericksburg,va C cudaman1969 master
cudaman1969 master C Joined: Jan 2004 Posts: 8,233 fredericksburg,va	Shafts must be short, USS North Carolina are that size, and this was first hand knowledge from two engine room guys from a carrier during WW2. They had a lathe that road a cradle with the man riding for the full length.

Re: Bent crankshaft causes and myths [Re: cudaman1969] #1562314 01/13/14 10:11 PM 01/13/14 10:11 PM
Joined: Oct 2011 Posts: 515 geezer acres rest home D dakotawilly mopar
dakotawilly mopar D Joined: Oct 2011 Posts: 515 geezer acres rest home	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....

Re: Bent crankshaft causes and myths [Re: fourgearsavoy] #1562315 01/13/14 10:12 PM 01/13/14 10:12 PM
Joined: Jul 2008 Posts: 30,424 Florida STAYcation dOc ! The village idiot's idiot
dOc ! The village idiot's idiot Joined: Jul 2008 Posts: 30,424 Florida STAYcation	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 ?

Re: Bent crankshaft causes and myths [Re: dOc !] #1562316 01/13/14 10:33 PM 01/13/14 10:33 PM
Joined: Oct 2011 Posts: 515 geezer acres rest home D dakotawilly mopar
dakotawilly mopar D Joined: Oct 2011 Posts: 515 geezer acres rest home	absolutely!!!!!if you don't like the weather in ohio,stick around 5 min it will change..... SFI 25.5 depends,no leak,even at 213 mph....

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