[steve25]

I would like to get a discussion going as to what takes place in a running motor when the oil gets airated and the cut in stone rule of nature that you can’t compress a liquid goes out the 10th floor window.

I am sure there has been a good number of unexplained engine losses due to this and I have read about such, have any of you folks?

[Dragncar]

This is exactly why I made my own oil pump pickup and enlarged the low pressure side a bunch.
I have fantastic solid oil pressure. Now the oil pump-pickup and Steffs pan are married together.
If I use the pan on a different engine they all go together, used or not.

[Half-Inch Stud]

Cut-in-stone oil rules:

Any oil is better than no oil.
Any other oil is better than just any oil.
Oil is better than aerated oil.
The oil pump cannot lie, but the oil pressure sensor and gauge can lie.

Avoid aerated oil in and out of your oil pump.

[Steve C.]

Cavitation ?

"While most applications – whether stock or performance – use a wet sump system, it should be noted that they have some rpm limitations. There is a physical limit related to rpm on a wet sump, where once that threshold has been crossed, the gears or rotor sets can no longer continue filling with oil, and cavitation will begin. This happens typically somewhere between 6,500 and 7,500 rpm, but may occur at lower or higher rpm levels."

https://www.enginebuildermag.com/202...umps-and-pans/


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[mgarblik]

When I was preparing my SD-455 engine for the dyno, on a completely dry engine, I put 5 quarts of oil in the engine. Attached the drive rod and the drill. It made about 60-65 PSI with the 1/2 inch drill for about 45 seconds to 1 minute Then the sound of the drill changed and the oil pressure began dropping down to 30-35 PSI. I was stunned. So it did the test 3 more times. Each time, the same results. It was running out of oil and aerating what was left. I added 1 more quart of oil and problem went away completely and everything looked great on the dyno. Oil level is more critical on our Pontiacs than I ever would have guessed. 10W-30 oil, stock oil pan and pick-up. Stock 80# SD pump.

[Sirrotica]

Oil can't be compressed, aerated oil isn't oil, or a fluid, it's foam and the gas in it can be compressed.

Fluid carries heat much better than foam does so aerated oil will let bearing surfaces heat up from lack of lubrication, as well as fail in removing heat from the area where friction is being concentrated due to gas being whipped into the oil.

Certain oils and additive packages release the gas more rapidly than others, so they can make the aerated oil act more like a fluid than a foam, Putting faith in the oil to band aid a mechanical problem in the oiling system is a risky move. As the additive package ages, the ability to release the gases slows down making the bearing surfaces more susceptible to foaming.

The oil and system are the lifeblood of your engine, all the forged, and billet parts are worthless without an efficient oiling system.

These are the things I consider when designing the oiling system in an engine I'm building......YMMV

[Half-Inch Stud]

Originally Posted by mgarblik

When I was preparing my SD-455 engine for the dyno, on a completely dry engine, I put 5 quarts of oil in the engine. Attached the drive rod and the drill. It made about 60-65 PSI with the 1/2 inch drill for about 45 seconds to 1 minute Then the sound of the drill changed and the oil pressure began dropping down to 30-35 PSI. I was stunned. So it did the test 3 more times. Each time, the same results. It was running out of oil and aerating what was left. I added 1 more quart of oil and problem went away completely and everything looked great on the dyno. Oil level is more critical on our Pontiacs than I ever would have guessed. 10W-30 oil, stock oil pan and pick-up. Stock 80# SD pump.

Yes. 3 decades ago on this site i used to advise checking oil level by pulling a right turn and watching a responsive oil gauge drop (or not). Add until oil level didn't drop. Usually a 1-2-quart overfill on a 455. And remove the dipstick assy because it was useless.

As for the stock baffled pan, same thing but you could keep the dipstick assy functional.

These days, I'd run a gauge and a brite idiot swichted light. Would be nice to verify or adjust the idiot switch setpoint.

[steve25]

What is stated in post #5 is what I have seen take place also .

In about 40 seconds time depending on the hp and speed of the drill you prime with even a 60 psi pump will have pumped 3.5 QTs or more out of the pan and into the motor .

And this is without the motor running so where talking no added rocker supply or bearing related bleed taking place .

While a stock type windage tray is nice you must drill out the center drain holes much larger and add two or 3 more.

There no question that the pick side of the pump needs a large supply of oil that has not been run through the motor yet so not got any air in it .

For even a boring 20 second long 1/4 mile pass the stock 5 QTs in the pan cuts it just fine if the motor does not rev over 6K.

A oval track or cross country race motor needs every effort made to give oil rest time for the air to work its way out.

My hat is off to the oval track engine builders who got there motors living through 500 mile races up at average of 8000 rpm .

[Steve C.]

Consider how much oil is contained up inside a running engine.

If using one, calculate the amount of oil inside the lines to and from a remote mounted filter. My remote lines take about 1/4 quart of oil.

Another tidbit... many popular oil filters do not hold one quart. My large WIX filter actually holds about 3/4 quart.

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[sdbob]

Reading what you guys have done. I usually run the drill then slowly turn crank with bar. Also Steve I've drilled smaller holes on side of wind age tray where oil flips off crank,keeping from aerating oil ,so also it gets back to sump quicker.but I'm no expert just thinking in the backyard.