Oil myths

[KE7JFF]

Originally Posted By: AuthorEditor
Myth: I know better than the car manufacturer what spec. oil to put in my car because my butt tells me so! All of those engineers just waste their time all day and throw out some numbers off the top of their heads.


You laugh, but I once met an long retired engineer from AMC; he drove a 1994 Jeep Grand Cherokee with this custom EFI system to replace the Mopar EFI and injectors. I asked him what oil he runs for sport; he mentioned he runs Mobil 1 at 20W50 and his reason was "the person at AMC who suggested that came from Ford who thinks there is only one oil for all cars"

 

[Garak]

Originally Posted By: deven
Most of what you said is true. To add to your comment about friction modifiers, yes you do want less except having a decent amount of MOS2 is not a bad thing because MOS2 has micro polishing abilities that can help during the break in process.

Actually, if you have a really high amount of moly, it does function is an anti-wear compound, too.

FordCapriDriver: I suppose the question as to whether new vehicles are already broken in or not is kind of difficult to answer. I really can't answer that, other than that I'd say a rebuild is different than a new car, and this isn't the 1950s any longer. You know how it is here. People buy new vehicles and have problems, no matter what "procedures" they tried. Others have no problems, despite what they did or didn't do.

2015_PSD: Certainly, new vehicles have synthetics, and probably friction modifiers in them, too. But, the OEMs usually say keep it in. And, a new car isn't necessarily the same as a rebuild. There are some very knowledgeable posters here that do dump factory fills early (and would probably do the same with rebuilds). I'd avoid the synthetic in such a case out of cost as much as anything else.

At least I can prove that a conventional at regular price is cheaper than a synthetic at regular price. All the "slipperiness" arguments are a little harder to back up.

 

[UNC151]

Originally Posted By: Garak
2015_PSD: Certainly, new vehicles have synthetics, and probably friction modifiers in them, too. But, the OEMs usually say keep it in. And, a new car isn't necessarily the same as a rebuild. There are some very knowledgeable posters here that do dump factory fills early (and would probably do the same with rebuilds). I'd avoid the synthetic in such a case out of cost as much as anything else.
I am in the "dump the factory fill early" club.

 

[Garak]

I would consider myself there, too, but it's been a while since I had a brand new vehicle. The G37 was used, but got its service fill dumped immediately, and thankfully. It was overfilled by well over a litre.

 

[deven]

Originally Posted By: Garak
Originally Posted By: deven
Most of what you said is true. To add to your comment about friction modifiers, yes you do want less except having a decent amount of MOS2 is not a bad thing because MOS2 has micro polishing abilities that can help during the break in process.

Actually, if you have a really high amount of moly, it does function is an anti-wear compound, too.

Even in small amounts it is considered an anti wear agent.

 

[Garak]

By whom? There are formulators here who would disagree with that, and there have been some pretty big discussions on that matter before.

 

[deven]

Originally Posted By: Garak
By whom? There are formulators here who would disagree with that, and there have been some pretty big discussions on that matter before.

By definition MOS2 is a friction modifier. Friction modifiers lessen friction between two moving parts thus reducing wear.

 

[Garak]

No, friction modification and wear reduction are not the same thing. You can have accelerated wear while the coefficient of friction isn't changing, or reduce the coefficient of friction without correspondingly reducing wear. There are different mechanisms, too. Of course, there can be overlap, but moly does its AW stuff best at higher concentrations, and not all friction modifiers have useful AW contributions. The point being is that you can have oils with high AW concentrations and no friction modifiers, and oils with high concentrations of friction modifiers, with lower concentrations of AW compounds.

There are a couple good threads on it here somewhere, with Mola explaining the difference. There was one relatively recently (as in the last couple years) that involved Mola, Pontual, myself, and a few others. Maybe Mola will wander in here and remind us, since he'll be much better at explaining it than I will.

 

[zeng]

Originally Posted By: Garak
No, friction modification and wear reduction are not the same thing. You can have accelerated wear while the coefficient of friction isn't changing, or reduce the coefficient of friction without correspondingly reducing wear. There are different mechanisms, too. Of course, there can be overlap, but moly does its AW stuff best at higher concentrations, and not all friction modifiers have useful AW contributions. The point being is that you can have oils with high AW concentrations and no friction modifiers, and oils with high concentrations of friction modifiers, with lower concentrations of AW compounds.


+1

The mechanisms of friction reduction differs from that of wear reduction.
Just as wear reduction and anti-wear are not one and the same thing, though there is some relation.

 

[Jetronic]

Only if you have NO friction, you have NO abrasive wear. other than that, any combination is possible (including low friction/high wear)

 

[deven]

If the coefficient of friction is not changing and the wear is getting worse then there are other issues with the engine that is causing this wear. I'll try to locate SAE papers that I have read on friction modifiers that prove this.

 

[Garak]

Originally Posted By: deven
If the coefficient of friction is not changing and the wear is getting worse then there are other issues with the engine that is causing this wear.

Of course, but that doesn't affect what I said; in fact, it reinforces it. If you could yank the ZDDP from a specific oil, it's AW properties would be reduced, but the friction modification properties would not be impaired. Note that the flat tappet concerns didn't just disappear by someone dumping in moly by the bucketful.

Look at the method of ZDDP. It simply doesn't reduce friction. It does, however, reduce wear. The reverse happens with various friction modification compounds. Of course, yes, you will find compounds that can accomplish both, at least under certain regimes.

I'd suggest asking edhackett or Mola, since they have been most adept at explaining it, and far better than I have ever been able to. Jetronic makes a very understandable point, in that you can have any combination possible, including low friction and high wear. In fact, that's what formulators are dealing with right now with GF-6B coming out - you're reducing friction and viscosity as much as you can to the point you're in boundary lubrication. How do you prevent accelerated wear?

 

[BrocLuno]

Myth number 39 - you can't mix oils...

But we all do on a trip when we need to top up.

When I worked lube rooms, we'd use the bottle drain-off's (accumulated) for our own cars and trucks, and some guys had been doing that for decades.

We also did the odd hard-up customer oil change that way (1/2 price). Never an issue

I'm still a part time mixologists

 

[OVERKILL]

Originally Posted By: BrocLuno
Myth number 39 - you can't mix oils...

But we all do on a trip when we need to top up.


What?? Naw man, a true BITOG'er keeps the same oil he's running as a top-up in the trunk or hatch

I never mix.

 

[deven]

Originally Posted By: Garak
Originally Posted By: deven
If the coefficient of friction is not changing and the wear is getting worse then there are other issues with the engine that is causing this wear.

Of course, but that doesn't affect what I said; in fact, it reinforces it. If you could yank the ZDDP from a specific oil, it's AW properties would be reduced, but the friction modification properties would not be impaired. Note that the flat tappet concerns didn't just disappear by someone dumping in moly by the bucketful.

Garak I understand what you're saying. I think I'm not getting my point across correctly.
I guess what I'm saying is if you were to yank both ZDDP and Moly altogether we would see metal to metal contact faster. Then taking that same lubrication vessel and added a little Moly to it we would see metal to metal contact a little less faster because the added moly to the oil would reduce a little friction and in turn it would help reduce a little wear.

 

[crazyoildude]

I always told my customers throughout the years to use the oil it tells you to use in the owners manual it worked well since day one.

 

[Garak]

The main point, however, is that an oil with high AW levels and low friction modifier content is best for break in. I discussed that extensively with a formulator here. In fact, I learned how a dedicated race oil wouldn't be an appropriate break in lube, because while it should have sufficient anti-wear levels, it will be highly friction modified, too, which will be counter-productive.

 

[BlueOvalFitter]

Originally Posted By: deven
I own 3 speed shops and we assemble and disassemble a lot of engines. I can tell you without and iota of doubt that conventional oils do a MUCH better job at seating rings. Conventional oils do produce a little more heat and friction and goes a long way in honing cylinders and seating rings.

+1. ^^^THIS!^^^
When I used to build engines and race, I used a 50/50 mixture of SAE 30 wt. oil with STP oil treatment while assembling the engine. The engine was filled with SAE 30 wt. oil and the cam was broke in for 20 minutes at 2K rpm. I then drained the oil, changed the filter, and either used 10W30 or 5W30 conventional oil for the first 500 miles. After that, it was changed every 3-5K miles.

 

[Garak]

Deven might know for sure, but I'm relatively certain that RP's break in oil is a monograde, too.

 

[TiredTrucker]

Goes to prove an idea that I have had for quite some time... that engines are like small caliber rifles.

If I take a couple of fine made .22 rifles to the range, feed them both the same quality ammo, I will still get two different results. Neither the rifles or the ammo are at fault. Just that rifles will tend to shoot better with some brands and less so with others. One of those little mysteries of life. From my experience, motors (even within the same brand and engine) and oils are strikingly similar to the rifle / ammo mystery. Some engines will show benefit from particular add pack components, while others won't.