Gravity bends a crank?

[ford38v8]

If she's the same Molly I once knew, she personally bent many a shaft in her time.

[FrankWest]

Originally Posted by ford38v8

If she's the same Molly I once knew, she personally bent many a shaft in her time.

In the scifi film Forbidden Planet several space ship engineers were commenting on a new piece of scientific equiptment and one said,
I bet every Quantum Mechanic in the force would love to get his hand on this!
Funny

[glennsanders]

Know that's some funny stuff that there is.

[FrankWest]

Still many strange and unknown things exist. Maybe there is an unknown property of the metal in the crank that could create some strange phenomena so you better store your your crank in the vertical position just to be safe. After all, science for over a hundred years could not account for the fact that bumble bees can fly because their wings are too stubby to lift their big body aerodynamically...
But with recently with ultra high speed photography they found that the bumble bee does not flap his wings up and down as previously thought but rather front to back. So aerodynamically the bumble bee should not be able to fly but accounting for fluid flow dynamics of air with front to back flapping, more lift is actually generated. Maybe some day aircfaft designers will employ this principle to generate aircraft with greater lifting capacities.

[rheltzel]

At the risk of getting serious, years ago my buddies and I bought a NOS 99A crankshaft from the Ford dealer in Pinedale, WY. It was in a wooden shipping box which obviously was intended to be shipped and stored in a horizontal position, suggesting Ford wasn't very concerned about the effect of gravity on its famously stout crankshafts.

[rowens55]

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Originally Posted by rheltzel

Molly Cules...she worked at the cafeteria next to the crankshaft foundry at the Rouge plant. Was said to have inspired the workers to make sure their crankshafts were always straight, even if they were laid flat.

HAHAHAHAHAHAHAHAHAHA-puke-HAHAHAHAHAHAHA

[5851a]

I feel better storing a crank laying on the floor, if I store anything standing up I'll knock it over before I get around to using it.

[FrankWest]

Originally Posted by 5851a

I feel better storing a crank laying on the floor, if I store anything standing up I'll knock it over before I get around to using it.

True, if you store it balanced on edge it may fall over and break something.

[40cpe]

In the past a picture was posted here on the 'Barn showing a rack that would hang the crank by it's flange. Do you s'pose they will stretch?

[my4dv8]

So it's true if you lave a crank laying on its side long enough it will eventually turn into flat steel plate as it succumbs to the evil forces of gravity. I stand mine up cos it's more convenient.

[bbrocksr]

Originally Posted by tubman

I have always been amazed at discussions like this. Here's a crankshaft that can take the firing impulses running in an engine for 90-100K miles, and some prople wwill think it will bend sitting on a floor? Give me a break!

Cast iron cranks will definitely sag if stored horizontally and not supported correctly! The longer and heavier they are the more apt they are to sag. If you don't believe it you just haven't experienced it yet.
A Model A crank which is shorter, lighter and made of steel is not so apt to sag if stored horizontally.
Bill

[rheltzel]

Originally Posted by bbrocksr

Cast iron cranks will definitely sag if stored horizontally and not supported correctly! The longer and heavier they are the more apt they are to sag. If you don't believe it you just haven't experienced it yet.
A Model A crank which is shorter, lighter and made of steel is not so apt to sag if stored horizontally.
Bill

And you base this assertion on what empirical evidence?

[Bulligen]

Now all us old guys have a reason for our middles being thicker, Gravity is squeezing our ends together and that is over a period of 60 years!!

[rheltzel]

Only if your middle is made of cast iron and you spend a lot of time in the horizontal position.

[bbrocksr]

Originally Posted by rheltzel

And you base this assertion on what empirical evidence?

Sixty three years actual experience building engines, from flatheads to diesel engines and aircraft engines.

How about your actual engine building experience?
Bill

[rheltzel]

It pales by experience. If you know for a fact, based upon 63 years of building engines, that storage of a flathead Ford V8 crank in a horizontal position results in a bent shaft, I guess that ends the debate. Still, your certainty on the point does beg the issue of how long a Ford flathead V8 crank must lay in a horizontal position before it is ruined by gravity. Are we talking months, or years?

[itslow]

Store it in whichever position is most convenient.

They're stored on end at machine shops because they take up less floor space, not because of any distortion concerns. If any bending due to horizontal storage is a concern, then distortion due to vertical storage should be an even bigger one, as it would cause all the journals to bend.

[bbrocksr]

Originally Posted by rheltzel

It pales by experience. If you know for a fact, based upon 63 years of building engines, that storage of a flathead Ford V8 crank in a horizontal position results in a bent shaft, I guess that ends the debate. Still, your certainty on the point does beg the issue of how long a Ford flathead V8 crank must lay in a horizontal position before it is ruined by gravity. Are we talking months, or years?

I'm not saying the crank is ruined, I'm saying it will sag if not properly supported. When it is in the engine it is supported by the main bearings. Laying horizontal on the floor or bench it is supported on a couple of counterweights
When I first became aware of the problem it was a fresh ground cast iron 6 cyl crank. I installed it in the block and when I torqued it up it locked up. When I loosened the caps it turned but not freely I removed the maincaps and checked the runout with a dial indicator, It had about.005 . My first thought was the crank grinder had some how screwed up. I left it laying the block for a few days while working on another job. When I came back and tried it again it turned freely so I torqued it up and it still turned freely. This crank had laid on a steel workbench unsupported for probably 2 months since returning from the crank grinder. When it was installed in the block and properly supported for a few days the sag disappeared.

Just to clarify, Gravity will cause a crankshaft to sag, not bend. And the problem is worse on a cast iron crank than a steel crank. Also the problem is worse on a long crank than a short crank.
A Ford V8 crank stored horizontally and "properly supported" would not have a problem, If improperly supported could have a problem.
Most crank grinders store them vertical to prevent that problem. Bill

[JWL]

I have machined Flathead cranks from all walks of life and found absolutely no difference related to storage conditions. Frankly, the cast iron crank might be LESS likely to "sag" than the steel crank. If gravity damages a crank in the horizontal position just imagine how badly damaged it will be when stored on end!! If you have ever straightened the crank from a wrecked engine in a crank press you will see how far it must be moved to overcome "spring-back".

[BILL WZOREK]

Originally Posted by JWL

I have machined Flathead cranks from all walks of life and found absolutely no difference related to storage conditions. Frankly, the cast iron crank might be LESS likely to "sag" than the steel crank. If gravity damages a crank in the horizontal position just imagine how badly damaged it will be when stored on end!! If you have ever straightened the crank from a wrecked engine in a crank press you will see how far it must be moved to overcome "spring-back".

With all respect due you - - - - isn't this sending a mixed message ?