Another myth put out to pasture

[tubman]

I am in the process of building a 258" engine for my "t" tub. I had two crankshafts that had been stored on the floor on their sides wrapped in plastic for at least 20 years. I took them both to the machine shop to be checked and have the best one prepped to use. It turned out that the were both good, so we decided to use the one that looked the best, which cleaned up at .010-.020. Knowing that there is some controversy about storing crankshafts, I asked the machinist to check them both for run-out. He said both were less than .003, and in any event, turning them .010 or more would render even that small amount of no consequence.

[texas webb]

Good to know.

[37 Coupe]

How does this put the myth to rest? If properly stored they should have no run out. I wouldn't be happy checking for run out on a shaft of any type and finding .003.

[Kube]

Originally Posted by tubman

I am in the process of building a 258" engine for my "t" tub. I had two crankshafts that had been stored on the floor on their sides wrapped in plastic for at least 20 years. I took them both to the machine shop to be checked and have the best one prepped to use. It turned out that the were both good, so we decided to use the one that looked the best, which cleaned up at .010-.020. Knowing that there is some controversy about storing crankshafts, I asked the machinist to check them both for run-out. He said both were less than .003, and in any event, turning them .010 or more would render even that small amount of no consequence.

Yep, a sample of two cranks proves that the myth has now been put to rest forever. This 'test "makes me so happy to know you do not work for a pharmaceutical company. I can hear it now "yep, we tested those pills on two people and neither one died. We're good to go!"

[Kube]

Originally Posted by 37 Coupe

How does this put the myth to rest? If properly stored they should have no run out. I wouldn't be happy checking for run out on a shaft of any type and finding .003.

Very good point indeed! Your perspective is apparently one from an educated background in metals and / or metal working.

[tubman]

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Fine. Feel free to scrap all of your crankshafts with less than .003 run-out. Not me.

[Ronnie]

Hey Tub it didn't take long did it!!

R

[tubman]

Originally Posted by Ronnie

Hey Tub it didn't take long did it!!

R

Yeah, that was quick. I wonder if I should set up one of those threads with a poll on whether I should put this build on indefinite hold!

[37 Coupe]

Originally Posted by Kube

Very good point indeed! Your perspective is apparently one from an educated background in metals and / or metal working.

Yes and our machine shop stored shafts to be ground even for short periods either hung up vertically or supported horizontially. Someone besides me thought this was important enough as some of the storage racks were from the 20's and 30's.

[40 Deluxe]

So if this myth were to be true, then when hanging a crank by the front counterweight the crank is going to stretch, what with 80% or more the of crank's weight suspended off-center (2 inches off-center in the case of a Merc crank)!

[40 Deluxe]

Originally Posted by 37 Coupe

Yes and our machine shop stored shafts to be ground even for short periods either hung up vertically or supported horizontially. Someone besides me thought this was important enough as some of the storage racks were from the 20's and 30's.

You don't think that maybe hanging cranks vertically is just the best way to utilize storage space?

[flatjack9]

So if you store it on end without hanging, will it compress over time?

[countrysquire]

Originally Posted by 40 Deluxe

So if this myth were to be true, then when hanging a crank by the front counterweight the crank is going to stretch, what with 80% or more the of crank's weight suspended off-center (2 inches off-center in the case of a Merc crank)!

If you hang them for a long enough time, you can use them in V-12s...

[40 Deluxe]

Originally Posted by flatjack9

So if you store it on end without hanging, will it compress over time?

The myth says yes!

[flatheadmurre]

Originally Posted by flatjack9

So if you store it on end without hanging, will it compress over time?

It will tip over and hit your toes....i know !!!
Trying to zigzag your way to the crankgrinder.....sooner or later they will get you

[bbrocksr]

Originally Posted by Kube

Very good point indeed! Your perspective is apparently one from an educated background in metals and / or metal working.

There are now two posters that understand metals and metal working.
Bill

[Ronnie]

Originally Posted by 40 Deluxe

So if this myth were to be true, then when hanging a crank by the front counterweight the crank is going to stretch, what with 80% or more the of crank's weight suspended off-center (2 inches off-center in the case of a Merc crank)!

No machine shop i have called on hangs a crankshaft by the counterweight!!

R

[47COE]

Originally Posted by 37 Coupe

How does this put the myth to rest? If properly stored they should have no run out. I wouldn't be happy checking for run out on a shaft of any type and finding .003.

But nobody knows how much runout they had when put into storage 20 years ago. Was it 0.000, 0.003, 0.006? Without knowing that it isn't possible to say anything about this "experiment".

[Newc]

Hi all; I had 3 merc cranks verticaly stored by leaning against the wall in '96. I was outside my shop going to work ,at about 5:30 am, and our 'spring break quake' hit, a 5.6 er. My shop sounded like a Sunday church call to services! Ding-dong-ding, One crank is cracked BAD, and I never checked the other two. You can't always win.. Newc

[40 Deluxe]

Originally Posted by Ronnie

No machine shop i have called on hangs a crankshaft by the counterweight!!

R

Even if you hang it from the center bolt, the load of the crank's weight is still 2 inches off-center (in the example of a Merc crank). So if the myth is correct, you will still end up with a distorted crank!

[itslow]

Originally Posted by 37 Coupe

How does this put the myth to rest? If properly stored they should have no run out. I wouldn't be happy checking for run out on a shaft of any type and finding .003.

Everything will have some amount of run-out to one degree or another. It is next to impossible to machine any turned shaft, whether it be a crankshaft or not, with absolutely zero run-out.

The real question is: What amount of run-out is acceptable for a Flathead crankshaft?

Lots of speculation on this subject by folk (both here and elsewhere) that have little to no background in mechanics of materials and are instead solely relying on hearsay.

[tubman]

OK. I have been looking all over the internet trying to find what the acceptable run-out should be for a flathead crankshaft. Very surprisingly, there seems to be no information on this. Just about everything I looked at said that proper bearing clearances are much more important than run-out. The one place I did find some actual numbers were on snowmobile forums. This is typical of what I found :

"I have heard between 2.5-3 thousands are factory spec so the question is how far does one let the crank get out of spec before repair? 4-5-6? What is a good measure to tell when the crank is on its last legs or could benefit from some preventative maintenance."

I have owned a few snowmobiles, and all of them had a red-line of over 10,000 RPM. From this, I have to believe that "less than .003" would be more than adequate for a flathead. Therefore, I stand by my initial statements.

I have spent some time and money determining these facts, which I believe will benefit the majority of members here.

I hate to have to say this, but unless you guys can come up with some solid, verifiable numbers, "37 Coupe" and "Kube": stay out of this thread; you have nothing to add but negativity, and that hurts everyone.

[Alaska Jim]

you guy's crack me up.

[Charlie ny]

Run out, I'm lucky if I can crawl out some mornings, yikes
Charlie ny

[40 Deluxe]

Thinking more about this alleged run-out issue: So we have a crank laying horizontally on a shelf for years. Since it is supported in several places by the counterweights no matter how you turn it, just where does this distortion occur? At the front main? Center main? Rear? At one of the crank throws?

[Old Henry]

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Why don't y'all just keep your crankshafts in your engines like I do? Haven't had mine sag in there.

[bbrocksr]

Originally Posted by tubman

OK. I have been looking all over the internet trying to find what the acceptable run-out should be for a flathead crankshaft. Very surprisingly, there seems to be no information on this. Just about everything I looked at said that proper bearing clearances are much more important than run-out. The one place I did find some actual numbers were on snowmobile forums. This is typical of what I found :

"I have heard between 2.5-3 thousands are factory spec so the question is how far does one let the crank get out of spec before repair? 4-5-6? What is a good measure to tell when the crank is on its last legs or could benefit from some preventative maintenance."

I have owned a few snowmobiles, and all of them had a red-line of over 10,000 RPM. From this, I have to believe that "less than .003" would be more than adequate for a flathead. Therefore, I stand by my initial statements.

I have spent some time and money determining these facts, which I believe will benefit the majority of members here.

I hate to have to say this, but unless you guys can come up with some solid, verifiable numbers, "37 Coupe" and "Kube": stay out of this thread; you have nothing to add but negativity, and that hurts everyone.

Are you saying that only posters that agree with you can post on your thread?
Bill

[tubman]

Originally Posted by bbrocksr

Are you saying that only posters that agree with you can post on your thread?
Bill

Not at all. Read my post again; If they have any proven, verifiable hard information, they are very welcome to post. We don't need any unverified opinions or off the wall theories. I spent a bunch of time and money determining what I did; I only ask that they do the same.

[Jim in Wisconsin]

In science it's very hard (maybe impossible) to prove a negative.
Having an example of something not happening only shows that it sometimes doesn't happen.
Having an example of something happening shows that it sometimes does happen.

Does anyone have an example of a crankshaft that was known to be perfectly straight (or of a known amount of runout and just where the runout was), and then stored it for a number of years on it's side and then re-measured it, and it had warped?
The burden of proof is usually on the person making the claim.

[rheltzel]

Molly suggests that those of you who still want to debate the point do a search on "gravity bends a crank", where the subject was exhaustively discussed: https://www.fordbarn.com/forum/showth...ty+bends+crank

[Mike in AZ]

tubman....what were your initial reading of runout on those cranks before your stored them?.....Mike

[oldford2]

Come on guys,
Too many guys on here that apparently have doctorates in metallurgy. If you have .003 runout that means the center journal is .0015 off center. Bolt that center cap and button it up. jmho
John

[tubman]

Originally Posted by Mike in AZ

tubman....what were your initial reading of runout on those cranks before your stored them?.....Mike

Boy, I wish I knew; it would explain a lot of things. At the time (about 25 years ago), a friend of a friend (a Mopar guy) asked me if I wanted 3 8BA's for $100. I said "Sure!" and took them home. I pulled them apart (they all came apart easily), and I covered them with oil, wrapped them in plastic, and stored them away.

If anyone can come up with Fords specifications on acceptable run-out, I'd really appreciate it. The thing to keep in mind however, is that even a run-out measurement of up to .005" would be eliminated by turning the mains .010 under.

[tubman]

Originally Posted by Jim in Wisconsin

In science it's very hard (maybe impossible) to prove a negative.
Having an example of something not happening only shows that it sometimes doesn't happen.
Having an example of something happening shows that it sometimes does happen.

Does anyone have an example of a crankshaft that was known to be perfectly straight (or of a known amount of runout and just where the runout was), and then stored it for a number of years on it's side and then re-measured it, and it had warped?
The burden of proof is usually on the person making the claim.

This is the sort of information I'd like to see, not unverified speculation.

Thanks, Jim

[Tinker]

Originally Posted by Mike in AZ

tubman....what were your initial reading of runout on those cranks before your stored them?.....Mike

Okay disclaimer. I don't know crap about nothing. But what was Henry factory specs. Were they perfect specimens of a thousands or 10 thou of a inch?

I don't know?

[countrysquire]

Sadly age is what really bends a crank...


Sent from my iPad using Tapatalk

[Ronnie]

Time to sweep this thread under the bench way too many wannabee crank specialists here must be something in the drinking water. "LOL"

Here is the same argument from 5 years ago https://www.fordbarn.com/forum/showthread.php?t=5509


R

[Karl]

I have a scientific mind but am not a metals specialist . My scientific mind tells me (with a little help from Harold Sharon) that the elastic range must be exceeded before plastic deformation. The elastic range of metal is huge and hence I believe that the force of gravity is not enough to cause cold creep. If the crank was made of something with a low elastic range eg peanut butter then we would see cold creep. If a crank will cold creep then surely all the camshafts in the world would be bent due to the force of the open valve springs on the cam-not to mention all the axles on parked cars in the world due to their orientation and the weight they are carrying. Again I can't prove this but applying common sense would suggest that cold creep in metal is not true .

[tubman]

Originally Posted by Ronnie

Time to sweep this thread under the bench way too many wannabee crank specialists here must be something in the drinking water. "LOL"

Here is the same argument from 5 years ago https://www.fordbarn.com/forum/showthread.php?t=5509

R

Ronnie,

You are absolutely right about "kicking this thread under the bench". I am very familiar with the thread you are referencing here, which is why I started this one because I had absolute, definitive information on the subject, which was not present in the thread you referenced. Unless someone has solid information to the contrary, I'm done.

Tubman

[Kube]

Originally Posted by bbrocksr

There are now two posters that understand metals and metal working.
Bill

Bill, I have an extensive background in tool & die. State indentured. I also have a degree in metallurgy. Spent many years as a tool maker, in charge of quality control of the tooling produced and requisite laboratory inspections of steel, etc.
That being understood (I hope) I can say with certainty that standing a crankshaft on end is the best way to store them.

Ya know, lots of different ways 'work". However, there is only one "best" way.
I try to keep in mind that not everyone graduated at the top of their class. Heck, judging by many of the posts herein, I have to wonder just how many actually graduated.

[Tinker]

Classic ford barn discussion.

Another forum same thing...
http://www.ford-trucks.com/forums/37...storage-2.html

[GB SISSON]

My crank has been unsupported for 62 years. At this point it is neither straight nor round, but all my flathead V8s run great with a minimum of attention. This has been a great and relaxing hobby. I jump behind the wheel, fire one of 'em up and race around having a good time. I have a micrometer, but it doesn't get out of it's case very often. It is supposed to be fun. It's a hobby. .003 isn't very much, and it grinds out, so we should all just do it how we like. If the saggy crank guys break down, they are the ones who have to walk home. I actually store mine upright because they take up less room!

[bbrocksr]

Originally Posted by Kube

Bill, I have an extensive background in tool & die. State indentured. I also have a degree in metallurgy. Spent many years as a tool maker, in charge of quality control of the tooling produced and requisite laboratory inspections of steel, etc.
That being understood (I hope) I can say with certainty that standing a crankshaft on end is the best way to store them.

Ya know, lots of different ways 'work". However, there is only one "best" way.
I try to keep in mind that not everyone graduated at the top of their class. Heck, judging by many of the posts herein, I have to wonder just how many actually graduated.

Kube Boy you've got that right!
Bill

[Old Henry]

I've just been studying these perpetual motion machines: https://www.youtube.com/watch?v=287qd4uI7-E.



Seems like the best approach would be to mount each crank to be stored on some kind of rotisserie apparatus powered by a perpetual motion machine (would probably need to be part of the totally balanced machine) to turn it continually without the use of any power for eternity and prevent sagging. Huh?

[Karl]

Originally Posted by Kube

Bill, I have an extensive background in tool & die. State indentured. I also have a degree in metallurgy. Spent many years as a tool maker, in charge of quality control of the tooling produced and requisite laboratory inspections of steel, etc.
That being understood (I hope) I can say with certainty that standing a crankshaft on end is the best way to store them.

Ya know, lots of different ways 'work". However, there is only one "best" way.
I try to keep in mind that not everyone graduated at the top of their class. Heck, judging by many of the posts herein, I have to wonder just how many actually graduated.

Well you learn something every day! I bow to your superior knowledge . Never to old to learn . I guess thats why I to graduated top of my class as well . However my class was fixing people rather than engines . In medicine we also find that our patients are better if they are upright and we use viagra to fix sagging in 50% of the population LOL Karl

[Tinker]

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Originally Posted by Kube

Bill, I have an extensive background in tool & die. State indentured. I also have a degree in metallurgy. Spent many years as a tool maker, in charge of quality control of the tooling produced and requisite laboratory inspections of steel, etc.
That being understood (I hope) I can say with certainty that standing a crankshaft on end is the best way to store them.

Ya know, lots of different ways 'work". However, there is only one "best" way.
I try to keep in mind that not everyone graduated at the top of their class. Heck, judging by many of the posts herein, I have to wonder just how many actually graduated.

Okay we have credentials out of the way, but as they say in grade school "show your work"

I don't disbelieve you, but I have only heard the argument of "because, that's why".

This is a hobby for me but it would be interesting to know why....

[outlaw]

I love this site, & I visit here many times each day. But sometimes I think that some of you guys have waaaaay too much time on your hands.

[flatheadmurre]

Ok lets do some science then.
If we have a piece of metal and dont go high enough on the wöhler curve it should go back to its initial shape...can we all agree on that ?
That means a crank stored in any way shouldnt deform by the weight only...
So there must be something more to this equation.
Castiron has something called aging and the theory in this case must be that the force bending the crank combined with aging should give a permanent warp.
Next step is to find out how much a crank bend from its own weight in a worse case scenario.
What timeframe is needed to make this permanent.
Now the metalurgy pros have to crunch me some hard numbers to prove their case.

[CT AV8]

How about a wooden cradle that supports the crank at each main bearing point for horizontal storage. You could use the bottom end as a pattern. It seems to me that would most closely mimic the way the crank is structurally loaded in an engine. With a little extra carpentry, the cradles could be palletized for stacking. I'm sure somebody's done this already.

[V8COOPMAN]

Originally Posted by flatheadmurre

Ok lets do some science then.
If we have a piece of metal and dont go high enough on the wöhler curve it should go back to its initial shape...can we all agree on that ?
That means a crank stored in any way shouldnt deform by the weight only...

A "Wohler" curve, sometimes also referred-to as an "S-N curve", is a means to plot or graph the magnitude of cyclical stress against the scale of cycles to the point of failure in a piece of steel. A "Wohler curve" specifically, has NOTHING to do with "meaning a crank stored in any way shouldn't deform by the weight only". DD

[flatheadmurre]

Originally Posted by V8COOPMAN

A "Wohler" curve, sometimes also referred-to as an "S-N curve", is a means to plot or graph the magnitude of cyclical stress against the scale of cycles to the point of failure in a piece of steel. A "Wohler curve" specifically, has NOTHING to do with "meaning a crank stored in any way shouldn't deform by the weight only". DD

From that you can get what force you can apply without any permanent changes.
But lets say im totally wrong and give me some hard numbers that says how much and how fast a crank deform.
And why it does so !

[alchemy]

Originally Posted by CT AV8

How about a wooden cradle that supports the crank at each main bearing point for horizontal storage.

If the myth that an unsupported cast iron crank will bend due to prolonged exposure to gravity is true, do you really think some lightweight wood will keep the cast iron from bending? Wood's density is WAY less than cast iron, and even cast iron can't hold up to gravity. The wood will probably be pulverized.







.

[Tony, NY]

Where are The MythBusters when you need them?
http://www.discovery.com/tv-shows/mythbusters/

[Ricardo39]

This is getting interesting, so...what about the storage of an engine block? If gravity can distort a crankshaft, can I think that a block in vertical position could suffer the same effect?

[Ronnie]

Whats next

[flatjack9]

OK , who's willing to measure a cranks run out, then store it laying flat for 20 years and report back your results? Then we'll all know( well whoever is still around). Personally I'm not going to worry about it.

[al pa.]

great response 47 COE.

[GB SISSON]

One of my flathead rebuild books has a diagram showing a plank with 3 blocks of wood attached to a perhaps 1" plank. The 3 blocks are cut into a 'vee' shape at each journal. Not being any kind of metalurgist or real mechanic, but a career woodworker, I thought nobody could build that accurately enough to make it support evenly. Even if it was originally built by a professional woodworker with extreme precision on jigs and fixtures, the blocks would shrink and swell at different rates and with the 'vee' design, shrinkage or swelling would raise or lower the support on the journal at the whim of the atmospheric conditions. Three steel tabs welded to an I beam might work if you ground the center one and used a feeler gauge when checking the center one but....zzzzzzzzzzzzz why?

[Tinker]

Originally Posted by flatjack9

OK , who's willing to measure a cranks run out, then store it laying flat for 20 years and report back your results? Then we'll all know( well whoever is still around). Personally I'm not going to worry about it.

Yep I think you have it. Maybe ford hung they're cranks becuase it was cheaper then creating a series of main supports for every crank or that it works. Who knows. Do what works for you.

I will take all merc 4" cranks laying anyway they are if ya want to drop them off. I'll sort them out at my cost.

I don't think anyone is wrong here I just think we all have different ways and respect that.

[itslow]

Originally Posted by Ricardo39

This is getting interesting, so...what about the storage of an engine block? If gravity can distort a crankshaft, can I think that a block in vertical position could suffer the same effect?

It'll make the cylinders go oval and make the block unusable.

Originally Posted by Tinker

Yep I think you have it. Maybe ford hung they're cranks becuase it was cheaper then creating a series of main supports for every crank or that it works. Who knows.

Cranks were originally hung or set on end for space conservation and ease of storage, plain and simple. Imagine how much floor space would be consumed if the cranks were stored horizontally.

[Jack E/NJ]

itslow>>>Imagine how much floor space would be consumed if the cranks were stored horizontally.>>>

OK, I imagine they wouldn't take up that much space if horizontally nested or just piled in a mountain of cranks in a corner somewhere. Carefully of course. And also no higher than the yield point of the cranks at the very bottom of the pile. 8^)

Jack E/NJ

[Mart]

Ford wouldn't have had the cranks around for very long. They would have been into cars and out the door in very little time. I'm terrible for storage, I just let 'em lie on the shelf.

Mart.

[CT AV8]

Originally Posted by alchemy

If the myth that an unsupported cast iron crank will bend due to prolonged exposure to gravity is true, do you really think some lightweight wood will keep the cast iron from bending? Wood's density is WAY less than cast iron, and even cast iron can't hold up to gravity. The wood will probably be pulverized.







.

Yes, I do. Density and compressive strength are different things. A flathead crank weighs 70 lbs. The main beating journals are 2.5" diameter and although I don't have one to measure, are about 1.5" wide for front and center with the larger rear around 2". This gives me a collective bearing area of 12.5 sq in. Divide 12.5 by 70#= 5.6 psi. Douglas fir has a compressive strength 7,239 psi parallel to the grain. It's not even close to being " pulverized".

[CT AV8]

Originally Posted by GB SISSON

One of my flathead rebuild books has a diagram showing a plank with 3 blocks of wood attached to a perhaps 1" plank. The 3 blocks are cut into a 'vee' shape at each journal. Not being any kind of metalurgist or real mechanic, but a career woodworker, I thought nobody could build that accurately enough to make it support evenly. Even if it was originally built by a professional woodworker with extreme precision on jigs and fixtures, the blocks would shrink and swell at different rates and with the 'vee' design, shrinkage or swelling would raise or lower the support on the journal at the whim of the atmospheric conditions. Three steel tabs welded to an I beam might work if you ground the center one and used a feeler gauge when checking the center one but....zzzzzzzzzzzzz why?

GB, I've seen those "V" cradles as well. I was thinking more in the shape of a bearing retainer. Drill 2.5" hole in wood and cut in half. The idea is to support the crank as it was originally designed to be. I guess deflection is caused by setting a crank on the counterweights placing too much load on the journals. Once you've gotten rid of the weird cantilevering effects, you wouldn't have to worry about minor swelling and shrinkage of the support. If you do, you can always use a PSL vs Doug fir.

[Mike B]

Do a Google Search for "locomotive crankshaft storage", the click on Google Images, first one I saw was of about 5 Locomotive cranks stored horizontally, and only supported on/near the ends.

[cmbrucew]

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Originally Posted by Mike B

Do a Google Search for "locomotive crankshaft storage", the click on Google Images, first one I saw was of about 5 Locomotive cranks stored horizontally, and only supported on/near the ends.

Locomotive crankshaft and camshafts can be 2 or 3 pieces bolted together.
Bruce

[itslow]

Originally Posted by Mike B

Do a Google Search for "locomotive crankshaft storage", the click on Google Images, first one I saw was of about 5 Locomotive cranks stored horizontally, and only supported on/near the ends.

Originally Posted by cmbrucew

Locomotive crankshaft and camshafts can be 2 or 3 pieces bolted together.

Point being?





How about one from a ship?



Sizes are increased compared to an automobile, but the concept and principles are the same.

[Mike B]

My point is they don't seem to be concerned with the crank deflection

[Jack E/NJ]

>>>itslow>>>

Bet my crank is bigger than your's. Looks like each big end in this photo gets it's own oil puddle.

Jack E/NJ

[47COE]

I saw that ship engine crankshaft too. The crankshaft weighs 300 tons. 38 bore x 98 inch stroke. 7790 HP for each of the 14 cylinders. I'd like to see the machine that grinds that crank.

[itslow]

Please refer to the thread "Gravity bends a crank?":

http://fordbarn.com/forum/showpost.p...&postcount=141

[tiger.1000]

EUREKA ! next time they send a space shuttle up, pack in a bunch of crankshafts! If a man can float in air, so can a crankshaft.....can't it ?

BUT.....

[flatheadernie]

What you need to do is keep all the warped ones is case of VAPOR LOCK LOL

[robert dick]

how do we know the shafts didn't have any runout when stored ?