VCCA Home Forums GENERAL DISCUSSION General Discussions Synthetic Blends

Lets see if I've got this about right.

a. Synthetic oil is 100 percent synthetic. So one brand is as good as another owing to the equal size of the molecules that make it up.

b. Regular oil is not as good as synthetic oil because the regular oil has irregular molecules and that tend to get in the way of each other as they go about being squashed together.

c. Blended synthetic is superior to regular oil on account that it has less irregular molecules to get in the way of the equal size molecules and thus causes confusion on which way the molecules should go to slip around each other.

(Bear with me.)

So my question is:

How much regular fossil oil can be added to synthetic oil to cause it to be labeled "synthetic blend?"

For instance if I were to buy Warmart blend would that be three quarts of synthetic and one of fossil?

How about if I bought Mobil? Would that be three and a half quarts synthetic to a pint of straight fossil?

How about if I bought Texaco would that be one quart of synthetic to three quarts of straight fossil?

Do we even know what each manufacturer uses for a ratio of non-synthetic to regular straight fossil to label their product "synthetic blend?" Is there a government standard? If so what is it.

And another thing what is meant by the phrase ( when talking about the longevity of oil): "oil breaks down." I didn't think oil broke down, I just thought it got dirty. That's why its recyclable.

Why is it said that you can run synthetic longer than conventional fossil motor oil? I don't understand why that is. Again something about the oil breaking down or something. Is it just the additives breaking down. Like STP does?

Isn't synthetic motor oil made from fossil oil? Is it something to do with getting the right sized molecules culled out from the other too big or too small ones? Who's in charge of that project: Goldilocks? Mercy!

Somebody set my head straight. Please.

Charlie

Some brands of synthetic oil is made from fossil oil. Castrol was one of the first to do this and it is considered legal by the oil institute and federal government.
Most semi-synthetic oils have about 20% synthetic.
Today you a farther ahead to mix your own synthetic making it about 50/00 ot buying a 100% syntheric when it is on sale with a rebate, etc.
I have been buying Mobil ! for just over $3.00 a Qt. Most places are getting $3.00 a Qt. or more for conventional oil.
If the bottle is marked Dexos it is a semi-synthetic oil that meets GM's spec for their Dexos oil.
Synthetic is not necessary in an "old car" under most conditions.
With an old car your better off buying a conventional oil on sale and changing it more often.. Around here Citgo is sometinmes on sale for about 1.50 a Qt.....and it meets all requirements.
I use synthetic in my modern and change it the same as conventional.
I have used synthetic in my old cars and found no problems, such as leakage, etc.
If you want the best of all worlds for an old car with a replacement camshaft or a 8 Cyl. engine get Quaker State Defy. It is a semi-synthetic with extra Zinc and available at Walmart at a reasonable price.

I'm not an expert on oil but I've read that synthetic oil isn't actually synthetic. This seems to support that.

Charlie,
I could try to explain mineral oil and compare it to synthetic but when I finished I am not sure you or others would understand it as it gets into some fairly technical Chemistry. Yes petroleum based oils are a "mineral oil".

I recommend that you do several internet searches and/or visit the major oil company websites to see if you can get some answers.

Without fully reading any professional papers on the subject what I have been told is that most oils are petroleum based but the synthetic variations come from the amount of "additives" that are put in.
Tony

Interesting discussion, but one option is left out. A knowledgeable engine rebuilder here suggest using only Diesel oil in these old engines. Says it significantly reduces issues of wear etc. Any thoughts?

Does he have a particular product that he recommends? Diesel oil is designed for certain applications ( higher loads and soot control ability etc.) and like passenger car oils there are many variations mostly determined by the additive package. A few years ago most diesel oils were 15-40 wt and had a higher zinc content, but like passenger oils they have changed considerably, mostly due to engine changes required to meet stringent emissions regulations. With a newly rebuilt engine current gas engine spec'd oil is perfectly adequate. Perhaps someone with an engineering background can shed more light on the subject.

Tony and others,
Mineral oils are refined and further processed from crude oil. They contain a mixture of saturated, unsaturated, linear and branched hydrocarbons. The mixture differs from producer to producer because of the source crude, refining/chemical processing and additive package. Several additives are added to decrease wear, oxidation, corrosion, neutralize acids, etc. Synthetics have chemically produced "base stock" from a crude oil based feedstock. The are basically saturated hydrocarbons with a controlled range of molecular weight, branching, etc. That makes them more stable (less susceptible to deterioration from oxidation, shear, etc). As with mineral oils additives are used to increase the performance and service life.

All those oils (mineral, synthetic, blends, diesel etc.) are formulated to meet or exceed SAE and vehicle (or equipment) manufacturers requirements.

End of Chemistry lesson for today.

Diesel oils no longer contain the "extra" zinc additive. They have to meet the same standards as gas engine oils due to the emission controls added to modern diesel engines.
That being said there are few engines that need more zinc that what is available in SL and SN rated oils. The exception would be for new cam break-in, a new cam of questionable quality or a high performance cam.

You can go to "Bob is the oil guy" site and read about oil for hours.

When all the hype is boiled down and we're left with no better oil for our cars than what the manufacture indicates in the manual, such as SL, SN etc, then anything we can buy at a higher price is just another example of "snake oil" and we're just throwing our money away. Can I get an "amen?"

So much for a chemistry lesson, huh, Chipper. Seems the work has been done for us and all we need to do is learn to read the little circle on the back of the can.

Charlie

Seems this matter comes up every now and then. Too bad the "search" thing doesn't work better. We could save a lot of space in here.

As for Charlie's request for an Amen....

Yes, Amen.

Bill.

Synthetic oil has several advantages. When cold it thickens less/flows faster. Like at below -20 Deg.. Holds its body better when hot.. Thickens less under hot weather hard driving. No small molcules to boil off and cause oil to thicken like tar.Under normal conditions there is little advantge other than the drain intervals can be extended somewhat.

I'm about to change the oil in the '32 with 10W30 detergent, not non-detergent. I'm told that as long as you change frequently, there shouldn't be issues with using detergent

But maybe I should put in synthetic instead?

One guy who uses synthetic (I can't remember the brand) tells me that it works great in his old cars. He thinks it sticks more to the bearings than regular oil.

Another person says the synthetics will leak more, but the engine was overhauled in 2000, so the gaskets should be good.

Trivia: the mechanics at the canning factory back home found that installing a continuous electric pump with big fat filter and synthetic oil was a tremendous advantage with something like double the life of the big diesel engines. You got oil at all the bearings before start up being a big advantage. Not doing that on these cars, of course.

It doesn't sound like synthetics really help.

Opinions?

If you are changing OVER to detergent from non-detergent then a more frequent change is probably recommended. The detergent oil will loosen up the crud that has probably built up which is what it's supposed to do. Not sure what kind of schedule is recommended and will leave that for the experts such as Chevgene or JYD or Chipper. Once most build up is removed then your normal schedule can be resumed.

Modern 10W-30 oil is light years better than any oil available in 1932. If the engine was rebuilt and driven little since 2000 it should have no sludge to worry about and use the regular 10w-30 oil.
Just a note about detergent oil It will not loosen chunks of sludge. It will slowly disolve some sluged and this will cause the oil to turn black......and synthetic oil is not necessary. I would change the oil every fall or every 1000 miles.

Thanks for the advice, I'll stick with 10W-30. The engine was rebuilt in 2000 and 10W-30 is the only thing that's been in it since. I don't have many miles since the last change 1.5 years ago, but it's time.