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!