Who am I kidding? My questions are never "quick"...

I finally switched my rebuilt engine over to synthetic oil today. Prior to today, all I have ever put in the engine was non-synthetic QuakerState 10w30. It has now been replaced with full-synthetic Mobil 1 10w30 (the stuff with the green cap). And, of course, I changed oil filters .

Anyway, whenever I put oil into the engine with a funnel in the past, it was a somewhat "slow" process of: filling the funnel with oil, waiting several seconds for the oil to drain down, and then filling the funnel again. I had to do this two or three times per quart in the past. With the synthetic, however, I noticed that I could pour the oil straight down and it went through the funnel nearly as quickly as it was draining from the bottle. I've never fillled an engine so quickly!

Wouldn't one expect, however, given that the oil weights are the same (10w30), that the synthetic would fill as slowly as the non-synthetic? I'm assuming that the speed at which the oil drains from the funnel gives some hint as to the viscosity of the oil (quicker = thinner oil).

Does this mean that the non-synthetic oil is actually much "heavier" (thicker) than 10w30 at atmospheric temperature?

I guess I just expected the different oils of the same weight to have similar viscosities.

Just curious...

Thanks!

 

i've noticed the same thing. i buy my oil in 5 qt jugs and have a quart sample bottle from work i measure quarts with. it has a 2" opening so when i pour a quart into the funnel i really have a quart right now and fill the funnel. i do believe synthetic flows much quicker. reason why, in simple terms it's slicker and flows better. scientific reason i'll guess has something to do with atoms, molocules, or something similar, but i don't know for sure.

 

Sancho,

You've just discovered one of the major benfits of synthetic lubricants. Imagine that petroleum "goo" trying to pump through the engine and actually lubricate anything when the temperature is 0° or below. It's even more vicous ("thicker") at 0°F. Try starting an engine at -35°, and you can begine to see the phenomenon in practical use.

If you invert the experimantal conditions, and raise the temperature to 180°F, that petroleum oil will pour like water, or faster, while the synthetic will still pour at the same rate. THAT is precisely why the synthetic will protect better. It maintains a more stable viscosity through a much wider temperature range. It will still pump, pour, and lubricate at very low temperatures, and maintain adequate viscosity to protect critical components at much higher temperatures. That's evidenced by many turbocharged engines requiring synthetic to satisfy the manufacturers' warranty requirements. Turbochargers get very hot, and only synthetic can lubricate effectively without sludge and carbon formation in the oil.

If you want to experiment further, put a quart of mineral oil and a quart of the same API viscosity synthetic in your deep freezer at 0°F or below.
Wait a few days, then pour test them again. Grab a cup of your favorite beverage, since the mineral oil is going to take about ten minutes to empty the quart container. If you don't want to pour them, just shake the container. You should be able to hear and feel the difference inside the plastic bottles.

Incidentally, Quaker State/Pennzoil is not even a very good example of mineral oil. They tend to use a much lower quality base stock and overuse fortifiers and polymers to thyicken and enhance the oil. Valvoline, Mobil, and Shell are probably much better mineral oils than Quaker/Pennzoil. But that's just my opinion and experience.

And Ed is correct. It isn't at an atomic or sub-atomic level, but it's a molecular thing. While mineral oil contains much more random molecular chain lengths, synthetics have a more controlled, engineered molecular size, allowing for a lot better control over the physical properties of the product.

 

I switched to synthetic by starting with a blend for the first oil change, then fully synthetic the next. Call me old, but I like to do things slowly and gradually.

Anyway, the blend was actually my first experience with any synthetic oil. When I went to install the new oil filter, I dipped my finger into the blend, then smeared it onto the filter seal.

Next I rubbed my finger and thumb together and they both almost flew off my hand from the force I had applied because I was expecting the same results as mineral oil.

MUCH SLICKER!!! And that was just the blend.

My wife got annoyed REAL quick because I wouldn't shut up about it. :sillylol: I tried to get her to rub it between her fingers, but she said she wouldn't have anything to compare it to since she never used mineral oil.

But yea, it's noticable. Cuts pour time in (more than) half.

 

So basically one should use synthetic oil instead of non-synthetic when replacing their car's oil?

 

 

Nate86: The only caution on that would be if you have a high mileage engine that has consistiently been lubricated with cheap, non-synthetic oil. Also, if it has not had regular oil changes, I would be even more cautious.

The reason for caution is that non-synthetic oil (especially the cheaper stuff) can produce solid deposits of oil in different places in the engine. When that solidified junk meets up with the synthetic oil, the synthetic will break the junk up and it can possibly end up in places it doesn't need to be (i.e. clog the sump). That's definately a Bad Thing.

I know, for example, that it would have been a very unwise decision to put synthetic in my engine before I rebuilt it. When I tore the engine down, the lifter valley was full of solid oil deposits that were just waiting to cause problems.

 

so should we still use 5W 30 synthetic?