Oil questions
Thread Starter
TECH Regular
Joined: Nov 2001
Posts: 409
Likes: 0
Oil questions -Is there such thing like a "semi synthetic" oil? I found some locally.
-Why is non synthetic oil recommended for engine break-in & what will happen if synthetic oil was used during engine break-in? (keep in mind that our cars came from the factory with Mobile1 for break-in).
TIA <img border="0" title="" alt="[Smile]" src="gr_stretch.gif" />
<small>[ December 19, 2002, 10:15 PM: Message edited by: xxxhp ]</small>
-Why is non synthetic oil recommended for engine break-in & what will happen if synthetic oil was used during engine break-in? (keep in mind that our cars came from the factory with Mobile1 for break-in).
TIA <img border="0" title="" alt="[Smile]" src="gr_stretch.gif" />
<small>[ December 19, 2002, 10:15 PM: Message edited by: xxxhp ]</small>
TECH Senior Member
Joined: Nov 2001
Posts: 7,234
Likes: 1
From: Mississauga, Ontario
Re: Oil questions There certainly are a lot of semi synthetic oils out there.
What it simply means is that the base oil (without additives) is made up of not 100% synthetic. A typical semi synthetic has about 10% synthetic base oil, and 90% conventional. The tricky part is that a lot of so called synthetics aren't even synthetic at all, but use a base oil which is known as a group 3 hydrocracked oil, which is petroleum oil that has had it's larger molecules refined to the point where they are smaller and uniform. But a true synthetic is created from scratch and does not use petroleum products, but instead uses polyalphaolefins and/or esters. So most of these semi synthetics contain 90% petroleum base oil, then 10% group 3, which is still petroleum. Thank Castrol for this blunder, they got the courts to recognize group 3 as synthetic, even though experts will agree it's not truly synthetic and is not as good as group 4 (PAO) or group 5 (ester) base oils.
The best semi synthetic on the market is called Schaeffer Supreme 7000. I'm using this oil and it proves itself to be as good or better than many full synthetics. This oil is unique though, it uses about a 25-30% PAO base oil, plus it's additive package is so perfectly mixed that it can handle long drain intervals over 10k without much viscosity change, and while having low oxidation rates, a very good TBN retention (meaning it neutralizes acids well for the entire interval), and it shows very low wear metals thanks to the combination of moly and another additive called Penetro. I'm currently starting a long drain interval test with this oil, seeing how far it can go. I will sample the oil (but not drain it) every 3k or so, to check it's condition and will only change it when it needs it.
As far as your other question, I honestly don't know why they still say not to use synthetic during break in, as it's 100% safe. Corvettes have come with synthetic as factory fill for many years and they break in just fine.
<small>[ December 20, 2002, 04:52 AM: Message edited by: Patman ]</small>
What it simply means is that the base oil (without additives) is made up of not 100% synthetic. A typical semi synthetic has about 10% synthetic base oil, and 90% conventional. The tricky part is that a lot of so called synthetics aren't even synthetic at all, but use a base oil which is known as a group 3 hydrocracked oil, which is petroleum oil that has had it's larger molecules refined to the point where they are smaller and uniform. But a true synthetic is created from scratch and does not use petroleum products, but instead uses polyalphaolefins and/or esters. So most of these semi synthetics contain 90% petroleum base oil, then 10% group 3, which is still petroleum. Thank Castrol for this blunder, they got the courts to recognize group 3 as synthetic, even though experts will agree it's not truly synthetic and is not as good as group 4 (PAO) or group 5 (ester) base oils.
The best semi synthetic on the market is called Schaeffer Supreme 7000. I'm using this oil and it proves itself to be as good or better than many full synthetics. This oil is unique though, it uses about a 25-30% PAO base oil, plus it's additive package is so perfectly mixed that it can handle long drain intervals over 10k without much viscosity change, and while having low oxidation rates, a very good TBN retention (meaning it neutralizes acids well for the entire interval), and it shows very low wear metals thanks to the combination of moly and another additive called Penetro. I'm currently starting a long drain interval test with this oil, seeing how far it can go. I will sample the oil (but not drain it) every 3k or so, to check it's condition and will only change it when it needs it.
As far as your other question, I honestly don't know why they still say not to use synthetic during break in, as it's 100% safe. Corvettes have come with synthetic as factory fill for many years and they break in just fine.
<small>[ December 20, 2002, 04:52 AM: Message edited by: Patman ]</small>
