Didn't want to hijack another person's thread.
In that discussion people say that one oil milks worse than others. Is there any truth to that? Is the milking the water being whipped up into the oil or is it excess alcohol? Are there oils that resist having that happen? Chemically what is actually happening that causes milking?

like a few said in the other posts....keep the idle mixture right, be sure to warm engine at the end of the day, vacuum pump helps a ton with moisture.

Keep the intake warm and you'll have no condensation dripping off the bottom side of it, milking the oil.

I have a friend who did a home test with oil and water. He took two different brands of oil and put them in jars with same amount of oil and same amount of water and shook them up. He said one brand separated the water from the oil in 30 minutes to a few hours. They other has still not separated and is milky after a few months. One brand was Valvoline VR1 Racing oil. I do not know what the other brand was or which one separated and which one did not.
So YES, some oils milk worse than others. still root cause of it is water and alcohol in the oil. To me it does not matter if the oil separates quickly or mixes in milking the oil it is not good for it.

As for the water? Well it is in the air the motor takes in. Alcohol runs cooler so it tends to have more of a milking problem than gas.
Water boils and evaporates out at 212* and alcohol about 160* and both at lower temps under vacuum.

The key is to get it good and warm at end of each race day, I get water temp up over 210* or so and then you see vapor coming out of the vacuum pump tank.

I HATE DRAGSTERS is right about the Idle mixture that is huge on how much alcohol you waste and how much moisture gets in the oil. If you can lean it does you warm up quicker use way less fuel and does not milk oil as bad.

As for oils fixing an issue, this is not want you should be concerned with! Fix the problem, there is no reason an alky feed motor should milk the oil, period! You don't want water or water vapor in the crankcase whether it's mixed with or separated from the oil, ever.

Usually it's idling to rich that causes the issue. When idling the engine should gain temp slowly without the fan running, this will get you close. The use of a vac pump will do wonders getting the moisture out along with never put the car away cold. The other thing that can help a bunch, especially for those using alky to double enter and cool the car while running, is use a primer plus gas system which will allow you to get the motor, and more importantly the engine oil hot before you park it in the trailer after racing.

I’d much prefer that my oil and fuel/water remain mixed. Compromised oil is not ideal, but it’s much better than your crank/rods spinning on a thin layer of straight fuel or water.

milk is simply moisture in i oil that should not be there. It can be from too much blow bye on rings letting alky into oil. Too rich system forcing unburned fuel into oil. It cn be from water from leak that gets into oil.

99% of time if running alky its i from over rich. Be it idle or just fat in general.

OK, so the milking is both alcohol and water in the oil. And some oils will keep it in suspension longer than others.

quote:

Originally posted by Eman:
OK, so the milking is both alcohol and water in the oil. And some oils will keep it in suspension longer than others.

Yes.... Not enough temperature will do it and too rich will do it. If an alcohol combo is excessively rich, it's slow to build temperature so it really compounds the issue. As others have said, if your tuneup is right and you keep your temps up, its pretty much a non issue. I stage at 155-160, don't use the fan unless I'm hot-lapping it and my car is pretty deadly - I change my oil about every 75 runs.