Mike C.

It depends... How hot is the room it's in? If close to the melting point of aluminum....

odurandina

can an engine bend enough to cause a problem ? that's for you all to decide. metal is not a solid until it gets extremely cold. until that point it is a semi liquid no different than glass. the **** bends. an engine needs to be on a flat surface. the first time i saw these engine stands, with the engine hanging over, i was like.... you got to be kidding me. best to rest it on a big rubber mat right on the floor when you're not working on it. have that block supported as much as possible.

once the cylider heads are on board the tendency for an engine to change it's shape is greatly reduced.



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Reimu

I really can't see this being true except for rare and strange circumstances.

Think about it: As long as people have been building engines (sometimes leaving them on stands in their garage for several years) wouldn't you think this would be common knowledge for car guys by now?

I just can't see a block being big enough to do this at a very alarming rate

luftpirate

Sounds like a great idea for a new Ebay product...

"New! - Crank Storage Rotator All Makes/Models +HP Free Ship"

carlege

i think that only applys to Guitars. Metal might be a different story

luftpirate

It's a huge problem with wing spars on 747s. That's why in 2011 the FAA is mandating all commercial airliners be stored in upside-down hangars.

vt951

http://en.wikipedia.org/wiki/Yield_(engineering)

Does an engine sitting on a stand bend? Yes. Permanently? No. "Plastic deformation" only occurs in metals if the stress exceeds its yield strength. Pretty unlikely that an engine which is designed for the loads of combustion to last hundreds of thousands of miles would see stresses exceeding yield strength while it's sitting still on an engine stand. I guess you might see yield around the bolts holding it on the stand, but that's not what the OP is asking about.

bader$

I wouldn't be surprised if it could bend if it hung there for a long time. I know a crankshaft can bend if left leaning against a wall and it gets real hot. The engine is much more rigid when it is complete. I never leave on on a stand if I am not working on it. Better safe than sorry.

Banshee

Lol but seriously, i love how so many people not just on technical forums, rather these forums which happen to have a reputation of friendly helpful people that can help you with any P car problem, are so close-minded that it just puts a sour taste in my mouth from even reading this thread. Its ridiculous.

krystar

i duno dood..i think i shoudl take that to prototype and ebay it. i'll def make some money

Damian in NJ

Normally I wouldn't believe this. But, years ago as a Bell Lab research scientist I saw a demo at a conference. Someone mounted a manhole cover on an optical table, took some holographic images, then put a DIME on the edge and retook the images. You could see the miniscule effect of the distortion of the weight of the dime on the manhole cover.

Mike C.

The microstructure of glass and metals are not the same. Glass is an amorphous solid - it is more like a very viscous liquid at room temperature. It does not have the crystalline regular lattice structure found in metallic solids. Two different animals...

derekvg

not many mechanical engineers on rennlist i guess??
it has nothing to do with strenght, or yield strength.

deformation of a material that is exposed to stress or pressure is called creep.
for example an engine on a stand.
because of the stress and pressure on the material, movements in the material on atomic level (yes there is) tend to happen uneven. this results in deformation.

is it enought for an engine to damnage? i dont have experience with it, and measuring would be extremely hard.
i think the spots where the stand is connected to the engine will deform, after some years for example.
the deformation in the center line bore will be too small to matter.

derekvg

dit found the information on wiki for those who want:

http://en.wikipedia.org/wiki/Creep_(deformation)

Oddjob

As a degreed and employed ME, I dont believe aluminum alloy pressure castings are subject to creep distortion below about 300 deg F. Certainly not at room temperature and certainly not at the low stresses that would be induced by the block's own weight.

And this aspect of materials science/engineering is pretty well known and studied, so auto manufacturers are not going to make engine blocks out of some poor material alloy that is subject to creep at low temps and stresses.


So, call it call it closed minded, but I am still saying this is a non-issue.