Teach me about Viscosity

[DragRace]

Never really paid that much attention to what it really was until I found this message board

How do you read /interpret
these readings?

For example:Vis @ 40C is 67.91 and Vis @ 100C is 12.05.

Thanks!

 

[Kitto]

This should help: http://www.bobistheoilguy.com/visc.html

 

[Merkava_4]

The main thing to remember is that oil has a natural tendency to thin out as it gets warmer; that's going to happen no matter what.

A 5w30 is the weight of a 5W oil when it's cold, then it becomes the weight of a 30W when it's hot. If you compare it to a straight 30W, it'll be thinner when it's cold than the straight 30W will be.

The cSt numbers are a visual reference of the oil's thickness at a certain temperature.

That's the explanation of viscosity in the simplest terms I can come up with.

 

[BrianWC]

FYI, it's best only to use the "W" when discussing cold viscosity-meaning don't use the term 30W.

 

[Merkava_4]

You're right, I should have said HD30 when referring to straight 30.

 

[Pablo]

I think this [ http://en.wikipedia.org/wiki/Viscosity ] is a relatively simple to understand description, but with enough in it to avoid statements like "cSt numbers are a visual reference of the oil's thickness at a certain temperature" (which maybe the author means a written visual unit of measurement to describe a fluid's kinematic viscosity at a specific temperature)

 

[Merkava_4]

If it makes you feel better. . . you can have a moderator delete my post and insert yours in its place; I really don't care.

 

[Pablo]

Sorry. Seriously - I meant no disrespect and I apologize if my post comes off as rude. I am no physicist, don't play one on TV and didn’t even stay at a Holiday Inn.

I'm sure mori or someone will correct something wrong in my post or at Wikipedia. Just the nature of the oil beast.

 

[AEHaas]

This would be of help:
http://theoildrop.server101.com/forums/s...ge=0#Post258506