Valve train wear vs. air humidity

[JAG]

What's worse: cold and dry or hot and humid?

The study below found says hot and humid is worse.

http://www.sae.org/technical/papers/981445
"Title: Investigation of Seasonal Effects on Valve Train Wear Measured With the Nissan Ka24e Engine Test
Document Number: 981445

Author(s):
Takashi Fujitsu - Showa Shell Sekiyu Kk

Abstract:
A study of seasonal effects on a low-temperature Vale Train Wear (VTW) test has been carried out with the Nissan KA24E engine test. Initial tests in our laboratory with this engine with an in-house reference oil showed that VTW was more severe in the hot and humid Japanese summer compared to the very dry winter. This prompted a systematic study of VTW performance using a temperature- and humidity-controlled cell, this being carried out with a JASO reference oil an an in-house reference oil. This work clearly showed that cam nose height loss correlated linearly with absolute humidity, higher wear being measured under higher humidity conditions. The slope of this relationship varied with the lubricant, presumably reflecting the differing sensitivities of lubricant formulations to humidity-induced wear. A relationship was also found between VTW and sulphate ion content of used oils. Overall, this study highlights the need to control ambient temperature and humidity for a low-temperature VTW test."

 

[Drew2000]

Geeez, how nuts can we get with this lubrication stuff? Remember, if you never start your engine, you have the least wear of all!

Drew

 

[Palut]

Don't you end up with corrosion if you never start your engine?

 

[AEHaas]

It was discovered some years ago that humidity was an independent factor in wear testing. ASTM engine tests were changed to specify a specific humidity range. The difference is not that large but it counts.

aehaas

 

[mechtech2]

Possibly the humid air doesn't cool as well.
It is less dense than dry air, because the H2O molecule has less mass than the O2 or N2 molecules .
This has got to be a very difficult test to monitor for reliable results. So much else can affect the outcome.

 

[Pablo]

The scary thing is that this makes sense to me. I've got to get away.

 

[jmac]

I was just wondering who is surprised at these results?
Maybe I've been around too many qualification tests and reports where it is a given that humidity effects anything electro-mechanical.
And I don't think it is due to cooling, rather the H2O molecule displaces the oil molecule allowing for less lubrication.
Want the lowest wear? Build an engine where all moving parts run in a vacuum, the ultimate 'dry' environment.

 

[SpitfireS]

Originally Posted By: jmac
I
Want the lowest wear? Build an engine where all moving parts run in a vacuum, the ultimate 'dry' environment.

You'll pick-up some HP too as the pressure difference under and above the piston is a little higher.

 

[moribundman]

Originally Posted By: JAG
What's worse: cold and dry or hot and humid?


What about cold and humid? That's what I got to deal with here right now.

 

[Eddie]

Gads. We need to get a life or see a Psychiatrist for a cure

 

[BarkerMan]

Humid air sure makes a difference on a dyno run, but how much difference would it make in valve train wear. Something to measure but would if effect the life of the engine as a whole? I don't think so.

 

[yannis]

Originally Posted By: Eddie
Gads. We need to get a life or see a Psychiatrist for a cure


Go tell Kasparov he is nuts.