What does the oil look like in yer engine at high revs?

[Steam]

Does the oil get all frothed and foamed up in the open spaces, or does it form a mist from all the whizzing spinning parts, or does it stay gluggy and mostly stuck to the parts, or what?
Does it get bubbly and aerated?

And how fast is it being pumped around by the oil pump? A couple of litres a minute, or faster? It would depend on the bike of course.

I was visualising a running engine the other day and I realised I don't really know how oil behaves when in extreme motion. Water I can imagine, we all know what that looks like when agitated. But not oil.

[007XX]

One completely uneducated guess...since it's being heated up by all the activity, doesn't it become more fluid? However, I would think that it probably would stay reasonably viscous...

maybe? :baby: Please teach me...

[ManDownUnder]

get an electric eggbeater and put it on high in a pan of warm or thin oil.... that's the stuff in your sump. Not frothy but agitated and splashing around a reasonable amount

That same oil is being squirted under pressure through jets and gallleries all around the motor (up to the head, onto bearings directly etc) so build that into the picture too.

Volume of oil being pumped around it a good question. Not sure although I'd expect it to be reasonably high (obviously related to engine speed).

[Ocean1]

Never seen a filum of it, would be interesting...

But yes it does get a tad less gluggy as it heats up.

As for what it looks like inside your crankcase? Most bikes are dry sump nowadays so there's usually no bloody great lake of oil lurking around down there for the crank to whip into a froth.

Safe to say there'd be a fair bit of mist though, and that's good, it's what lubricates the bottom of the cylinder.

[onearmedbandit]

Most bikes are dry sump nowadays so there's usually no bloody great lake of oil lurking around down there for the crank to whip into a froth.



Most bikes? Really?

[imdying]

Most bikes are dry sump nowadays so there's usually no bloody great lake of oil lurking around down there for the crank to whip into a froth.Most bikes are what now?

[Ocean1]

I've told you a fekin million times don't exagerate!

Allrightalready, SOME bikes, sheesh...

And it depends on who you ask as to what "dry sump" means. Some don't have a seperate oil tank but still have a scavenge pump.

[007XX]

....:confused: what's a sump?

Ok, never mind, you guys probably don't care much for the ABC

google is my friend....google is my friend...

[jrandom]

google is my friend....google is my friend...

Actually, Wikipedia (http://en.wikipedia.org/wiki/Sump) is your friend.

:niceone:

[007XX]

Actually, Wikipedia (http://en.wikipedia.org/wiki/Sump) is your friend.

:niceone:

Since I learnt that wikipedia is freely amended by members of the general public (aka: anyone that has an opinion :rolleyes:), I have decided to take its version of facts with a grain of salt...I like straight hard scientific facts, not the opinion of just any self professed know it all.

But thanks for the linky anyway :D

[imdying]

....:confused: what's a sump?

Ok, never mind, you guys probably don't care much for the ABC

google is my friend....google is my friend...

It's where the oil lives in probably 99% of 4 stroke bike motors.

[007XX]

It's where the oil lives in probably 99% of 4 stroke bike motors.

Ok, so is the little window on the right handside of my bike part of that? The one where I can see the oil's level?

[Steam]

Ok, so is the little window on the right handside of my bike part of that? The one where I can see the oil's level?

Yep, that's the sump inside there. It's where the oil goes to sleep at night.

[Motu]

Find a dry sump bike and remove the filler cap - you should be able to see the oil return pipe.Give it a few revs and see what comes out.Bare in mind that the return pump is twice the capacity of the feed pump.....but the volume you see is what the feed pump supplies.

[The Stranger]

Since I learnt that wikipedia is freely amended by members of the general public (aka: anyone that has an opinion :rolleyes:), I have decided to take its version of facts with a grain of salt...I like straight hard scientific facts, not the opinion of just any self professed know it all.

But thanks for the linky anyway :D

Actually Wikipedia is generally surprisingly accurate and self correcting.
Sure there are and always will be exceptions.
You really need to validate anything you get from the Internet anyway.

[homer]

you also are forgetting that a lot of the oil is passed around as vapour not just oil splashing about

[xwhatsit]

Since I learnt that wikipedia is freely amended by members of the general public (aka: anyone that has an opinion :rolleyes:), I have decided to take its version of facts with a grain of salt...I like straight hard scientific facts, not the opinion of just any self professed know it all.

But thanks for the linky anyway :D

LOL WUT

And KB is different how?! :lol:

When I was checking ignition timing, you pull of a little inspection plug on the flywheel cover while the engine is running. Wet sump yada yada. Whirry whirry! Splash. Wasn't frothy, though. Looked like normal oil except splashier.

[Delphinus]

Since I learnt that wikipedia is freely amended by members of the general public (aka: anyone that has an opinion :rolleyes:), I have decided to take its version of facts with a grain of salt...I like straight hard scientific facts, not the opinion of just any self professed know it all.

But thanks for the linky anyway :D

"Given enough eyeballs, all bugs are shallow"

If someone puts up something that is incorrect, because its open to the general public, it'll get picked up and corrected :)

[ElCoyote]

Does the oil get all frothed and foamed up in the open spaces, or does it form a mist from all the whizzing spinning parts, or does it stay gluggy and mostly stuck to the parts, or what?
Does it get bubbly and aerated?

And how fast is it being pumped around by the oil pump? A couple of litres a minute, or faster? It would depend on the bike of course.

I was visualising a running engine the other day and I realised I don't really know how oil behaves when in extreme motion. Water I can imagine, we all know what that looks like when agitated. But not oil.

Last night I spoke with one of the small people who work for Caltex and clean the inside of your engine They told me that at start up it was not unlike the Hooker falls and cruising it was like the Waikato river. I dare not say that out loud or Tainui will want a slice of the action or Uncle Helen will ask for carbon credits so consider this a whisper in a friendly ear. :niceone:

[pete376403]

"Grumpy" Jenkins (American builder of small and big block chev drag race motors in the 70's was interested in this question. He put windows into the side of engines to see what the oil was up to. Found that at high revs, most of the oil was wrapped around the crankshaft like a thick rope, killing power and also starving the pump pickup, leading to bearing failure. Deep sumps and windage scrapers to get the oil away from the crank raised power significantly. Dry sumping was even better. He said that at full revs there should be less than a quart of oil (out of a gallon or so) in the engine, the rest should be back in the tank (filter, cooler, pipes)
Even though its about car engines, his book "the Chevrolet Racing Engine" has a whole lot of good, useful information

[007XX]

LOL WUT

And KB is different how?! :lol:

.

:bleh: :laugh: Smartarse...

Difference with KB? A lot of the people on here I have met in person, and I can make my own mind up as to whether they are full of it or not, and therefor follow their advice...or not!


"Given enough eyeballs, all bugs are shallow"

If someone puts up something that is incorrect, because its open to the general public, it'll get picked up and corrected :)

Hmmmm, maybe in a perfect world...but it is still very much subjected to grey areas, ruled by personal opinions and preferences. Not sure I'd buy it, sorry!



On a more on topic note, I am very happy to report that the oil in my sump is looking mighty fine these days, after a much deserved oil change took place before my track day :2thumbsup