Benefits of Conventional over Synthetic

[cookiemonster]

Anyone here of the opinion that conventional oil is better than synthetics? and, why?

I've heard some people around the Internet say and write that that is what they believed, without elaborating to my satisfaction. So, I was wondering if there were any here that believed that and could explain.

 

[gfh77665]

The only one I can think of is that conventionals USED TO BE preferred as a break in oil. That is NO LONGER the case though. Some top end vehicles come with Mobil 1 or PP straight from the factory.

Other than that, just pricing, but that does not mean the oil itself is better than syns.

Some here will never, ever admit it, but despite that, syns are indeed better oils, to different degrees depending on the application.

 

[SilverC6]

It all has to do with cost and how much you enjoy maintenance of your vehicle.

A premium dino, like PYB at $16 and some change for a 5 quart jug, is an outstanding bargain today.

You can buy synthetic oil but your cost per mile goes up unless you extend your OCI.

So check your owner's manual and if it is permissible, dino at 5,000 mile OCI's will get you many, many miles down the road.

But if you don't change your oil religiously, using a premium synthetic oil will give you some peace of mind.

That way, when your wife tells you the car is 3,500 miles overdue, you'll have it covered.

 

[pbm]

I certainly don't believe that regular dino oil is better than synthetic but I do believe that some 'dinos' are very close to some of the lower priced syns. For instance PYB 5w20 is probably very close (if not better than) some of the off-brand syn 5w20's.

 

[jrustles]

Conventional oil is cost effective when your operating conditions push the use of synthetic into the 'diminishing returns' zone.

Basically, if you don't extend OCIs (ie not needing the utmost longterm oxidative stability) and you don't need any particular extreme high/low temperature stability, then today's conventionals are the smart choice IMO

 

[cookiemonster]

Thanks for all the answers so far.

I've heard that conventional oil is much better at holding particles in suspension than synthetic. Any truth to this?

 

[gfh77665]

Synthetics have a better formulation. Better base stocks, better additive packages. They are just better oils, all around.

 

[440Magnum]

There's no engineering advantage to conventional oil at all. Its purely a cost consideration. There's no truth to it "holding particles in suspension" better than synthetic.

It has been reported that Group III base stocks are better solvents for some additive components than Group IV, but that's a different kettle of fish than particle suspension.

 

[stickybuns]

Originally Posted By: cookiemonster
Thanks for all the answers so far. I've heard that conventional oil is much better at holding particles in suspension than synthetic. Any truth to this?


There was a time in the 1990's when Mobil synthetic gas engine aviation oil was destroying some engines. Mobil pulled it from the market and kept lawyers in Mercedes for quite some time. See http://www.avweb.com/news/news/182891-1.html?redirected=1

Some excerpts that sum it up if you don't want to read everything:

"Cylinder removal consistently revealed abnormal top-end wear, stuck and sludge-fouled oil control rings, and a thick coating of black sludge on the underside of pistons and on visible portions of the crankcase interior. "

"But it's those same smooth, ultra-slippery molecules that give synthetic oil its Achilles' heel: the inability to hold lead salts and other contaminants in suspension. The synthetic oil molecules are simply too [censored] slippery to hang onto such contaminants, so they settle out of solution and form sludge deposits, particularly in areas of oil stagnation such as prop hubs, oil pans, and the inside of pistons."

 

[stickybuns]

I would caution anyone thinking that Exxon-Mobil has not since solved these problems using the best scientists in the world. I think they just got caught with their pants down on that aviation fiasco. Their reputation took a huge hit. In the light-plane piston engine community, their are still mechanics & pilots who will not put in pure-synthetic, going with synthetic blends or non-synthetics only due to the 1990's experience.

 

[vintageant]

No doubt been asked many times before, but is there any downside to mixing syn & dino?
Say,for example, a syn Rotella T6 5W40 with a dino Rotella 10W30, 50/50, to create a syn/dino 7.5W35?

 

[wemay]

If your warranty limits OCI to 7500 mls or less, your spec's don't require anything special, and you don't want to deal with the hassle of rebates etc, then conventional may be a better choice for you.

 

[DR Racing]

Many HP cam grinders recommend dino racing oil in high valve spring tension performance engines. They report fewer cam failures and longer cam life with dino. This would not apply to a stock engine and syn oil is superior in that app. Dan

 

[CATERHAM]

Originally Posted By: SilverC6

A premium dino, like PYB at $16 and some change for a 5 quart jug, is an outstanding bargain today.

Plus the fact that PYB it is likely a GTL based synthetic oil anyway, as PQIA testing uncovered, so it's even more of a bargain.

But generally speaking syn oils offer a lot of advantages and the price difference when you compare the house brand API syn's to name brand dino's is often negligible so why bother with a dino, the PYB exception notwithstanding.

 

[stickybuns]

Originally Posted By: CATERHAM
.
Plus the fact that PYB it is likely a GTL based synthetic oil anyway, as PQIA testing uncovered, so it's even more of a bargain..


PYB is GTL? Evidence from PQIA? I saw a NOACK of 14% (SN 5w-30). Whats the evidence?

 

[Cooper]

It's cheaper?.....

 

[kschachn]

This is completely unrelated to an modern automotive synthetic oil. First off, the problem was with the lead in the avgas which obviously isn't an issue with automobiles. And second it was related to the fact that being an ashless oil there wasn't much in the oil in terms of any kind of additives to scavenge the lead. PAO is a poor lead scavenger by itself. So only if you had pretty significant blowby in the engine was this a problem.

An automotive synthetic in a automobile engine never was and never will be a problem like that which plagued AV-1, even if you are running leaded gas.

Originally Posted By: stickybuns
There was a time in the 1990's when Mobil synthetic gas engine aviation oil was destroying some engines. Mobil pulled it from the market and kept lawyers in Mercedes for quite some time. See http://www.avweb.com/news/news/182891-1.html?redirected=1

Some excerpts that sum it up if you don't want to read everything:

"Cylinder removal consistently revealed abnormal top-end wear, stuck and sludge-fouled oil control rings, and a thick coating of black sludge on the underside of pistons and on visible portions of the crankcase interior. "

"But it's those same smooth, ultra-slippery molecules that give synthetic oil its Achilles' heel: the inability to hold lead salts and other contaminants in suspension. The synthetic oil molecules are simply too [censored] slippery to hang onto such contaminants, so they settle out of solution and form sludge deposits, particularly in areas of oil stagnation such as prop hubs, oil pans, and the inside of pistons."

 

[wemay]

Originally Posted By: stickybuns
Originally Posted By: CATERHAM
.
Plus the fact that PYB it is likely a GTL based synthetic oil anyway, as PQIA testing uncovered, so it's even more of a bargain..


PYB is GTL? Evidence from PQIA? I saw a NOACK of 14% (SN 5w-30). Whats the evidence?


I believe he is ref the 5w20. But the inclusion of GTL for even that grade is still not a sure thing. A good assumption? Probably.

 

[bruno]

Last week I looked at the price of M1 synthetic in Walmart .... it was just under $23 for a five gallon jug / If the $7 difference means that much you ought to be walking .

 

[kschachn]

No they haven't solved it. Are there any full synthetic oils on the market for aviation piston engines? None that I know of, maybe you know of one.

One of the biggest reasons they haven't solved it is because of the arcane and restrictive rules that would not allow an additive formulation to properly handle the lead in 100LL. And like you mention there is resistance to change in aviation (sometimes for good reason). Pilots can be quite risk-adverse.

Originally Posted By: stickybuns
I would caution anyone thinking that Exxon-Mobil has not since solved these problems using the best scientists in the world. I think they just got caught with their pants down on that aviation fiasco. Their reputation took a huge hit. In the light-plane piston engine community, their are still mechanics & pilots who will not put in pure-synthetic, going with synthetic blends or non-synthetics only due to the 1990's experience.