Oil scraper function

[induction apprentice]

Im interested in a deeper understanding of oil scraper function. How exactly they collect and control oil.
Example being. Does the edge with a space of .020 to say .050 actually scrape oil off or just collect it and gather it into a pool to drain off. Does it set up a low pressure sucking oil off or does oil flying off the crank just smash into it and get collected disrupting its path to bounce back into the rotator some how. With all this. What role exactly does the clearance between the scraper and rotator achieve?
Is a sharp scraper edge better or worse than a rounded edge. Should we be machining it like a napier second.
Finally, how does it possibly nagatively or positively effect pumping loss.

I am right at the point of finishing one on a chevy and couldnt help but climb down the rabbithole thinking about its exact function?

[ProPower engines]

If you look below this thread there is a couple discussions on the subject that will explain it.

[induction apprentice]

If you look below this thread there is a couple discussions on the subject that will explain it.

Thank you.
I did look and went to the links on youtube. I watched the old guy make tea and observed his fluid streams and secondary flow explanations. I read how the dropplet size effects thier destination and so on. Yet I still believe I dont know anything about how scrapers really function and effect windage. So I am hoping someone on here has a good understanding of the dynamics of windage and scrapers and is willing to explain to me the real science behind them.

I would very much enjoy to learn about it fully.

Cheers!

[Spinkton]

Great topic. Really made me think. Read all the relevant data that propower recommended and felt that it was pretty inconclusive. Just generalized ideas we already know. And not much current information or testing. Would love to know and discuss more if anyone has and good experiences they like to share!

[ProPower engines]

If you look below this thread there is a couple discussions on the subject that will explain it.

Thank you.
I did look and went to the links on youtube. I watched the old guy make tea and observed his fluid streams and secondary flow explanations. I read how the dropplet size effects thier destination and so on. Yet I still believe I dont know anything about how scrapers really function and effect windage. So I am hoping someone on here has a good understanding of the dynamics of windage and scrapers and is willing to explain to me the real science behind them.

I would very much enjoy to learn about it fully.

Cheers!

Its not rocket science but dam close.
basically you want to remove oil wrapped around the crank and rods any way you can.
Thats it. Its up to the builder to figure out how to do it.

The drag that is caused by oil wrapped cranks is a lot of waster power.
Windage that foams the oil is also wasted power so the rule is
keep oil off the crank any way you can. Evert engine has different issues to deal with but there is no mystery behind it

[Walter R. Malik]

Im interested in a deeper understanding of oil scraper function. How exactly they collect and control oil.
Example being. Does the edge with a space of .020 to say .050 actually scrape oil off or just collect it and gather it into a pool to drain off. Does it set up a low pressure sucking oil off or does oil flying off the crank just smash into it and get collected disrupting its path to bounce back into the rotator some how. With all this. What role exactly does the clearance between the scraper and rotator achieve?
Is a sharp scraper edge better or worse than a rounded edge. Should we be machining it like a napier second.
Finally, how does it possibly nagatively or positively effect pumping loss.

I am right at the point of finishing one on a chevy and couldnt help but climb down the rabbithole thinking about its exact function?

With a wet sump system, it helps keep more oil in the pan and less up in the rotating assembly.
From some dyno testing, close proximity helps that kind of situation however, anything closer than about .375" usually costs a bit of power.
At around .375" to .400" it usually helps power.

[induction apprentice]

Thank you Walter. That is the kind of example of information why I am trying to dig deeper. I am not asking anyone to describe the basic function or idea behind a crankshaft scraper or windage tray. But believe the science goes much deeper for those who care to open their mind. I am sure some on here genuinely have a full understanding of the science in depth. I don't. I have tested windage trays on the pump and seen power gains. I have never tested a scraper on its own.
Questions that come to mind.
Does a scraper "scrape"?
Or "collect" already detached dropplets and or vapore.
Or does it suck the oil off by way of low pressure after the leading edge.
Should the leading edge be a radius or sharp or tilted.
Best design ideas.
Number and positiin and shape of any flutes or drains.
How to calculate best distance from different parts of the rotator.
How much power gained or lost.
How much less oil to walls.
What is actually going on in detail?
Like some have already pointed out. I realize it controls oil. That is not really the answer I am hoping for.

Anyone?

[PackardV8]

Some find power, some don't. I did a back-to-back test, limited to 6,000 RPM and a professionally built scraper didn't show any horsepower gain. Maybe higher RPM would show a benefit. This is a road race engine and it is hoped the scraper and windage tray will keep the oil in the pan.

[induction apprentice]

Mopar performance claims something like 15 or 20 h.p. from there windage tray. I tried the mopar one on the dyno years ago. I got a valid rusult. 17 h.p. peak gain on a 440. And was a very lousy pan. Shallow with a cube sump in the middle. I have steered toward the use of factory windage trays since. But it opens all kinds of questions for me anyways. In regard to scraper design and effectiveness. As well as when it should be used alone or in combination and so on. To me 17 h.p. is something that deserves attention.