Zinc vs Brass

[Tinker]

Just went by a local oil company and picked up 5 gallons of (600w) P680 oil for my A. Differential/Transmission.

While talking to owner/employee he mentioned that the P680 oil purchased does not have zinc in it and is better for gear sets that contain brass, as zinc is harder then brass.

Any thoughts on this???

[Uncle Bob]

You didn't mention a brand so couldn't check a data sheet, but he's likely correct. However he's also full of hooey. Zinc in lubricants is more correctly identified as zinc dialkyl dithiophosphate or ZDDP. It's in solution as a liquid, not as little beebees or whatever some might think. It reacts to temperature spikes caused by friction. I generally doesn't do harm to brass components because of their softness, not the other way round. Perhaps in his mind he confused the significant additive in most EP lubricants typically used for hypoid rear gears, that EP additive is a sulphur phosphorous compound that is reactive with yellow metals such as brass. Again, that's a chemical reaction rather than a physical or mechanical reaction.

[Tinker]

Bob,

Brand: Fina; Cylan cylinder oil.

It's does say, contains fats not corrosive to yellow metals.

[Special Coupe Frank]

600 / Steam cylinder oil / Heavy gear oil is still used in steam applications, antique car gear drives, and especially worm drives ( like elevator hoists ) which typically have parts made of "yellow metals"; Fordson tractors used worm drive, and the drive gear is a huge bronze piece...

Once Hypoid gears became common, in the late 1930's - early '40's, they required Extreme Pressure lubricants ( or an EP additive ), and most (?) gear lubes stocked by local auto-stores contained the sulfur based EP additives.

Wish one of my local oil companies stocked 600 / cylinder oil....

[Tinker]

Makes sense, Chemical reaction over a physical reaction.

Frank, I don't luck out very often but this was one of those times. They also have ethanol free gas.

Thanks guys.

[30blutudor]

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Originally Posted by Tinker

Bob,

Brand: Fina; Cylan cylinder oil.

It's does say, contains fats not corrosive to yellow metals.

I just changed the oil in my rear end and trans to 140WT with the EP additive. Should I change back to 600W to avoid damage?

[Tinker]

I can't really comment on replacing your oil, but I will say I paid about $10 a gallon for the Fina brand. 1qt of Lucas runs about $8. So if your buying any new oil it maybe worth a shot to find some.

[Special Coupe Frank]

Originally Posted by Tinker

I can't really comment on replacing your oil, but I will say I paid about $10 a gallon for the Fina brand. 1qt of Lucas runs about $8. So if your buying any new oil it maybe worth a shot to find some.

Suggest you buy all that they have, at that price !

[just plain bill]

Originally Posted by 30blutudor

I just changed the oil in my rear end and trans to 140WT with the EP additive. Should I change back to 600W to avoid damage?

I will state this again, until the restoration's started after WW2, probably 1960 ,no one was concerned about 600W oil. Most if not all automobile service stations used 90W for cars and 140W for trucks on their grease racks to replace or top up the transmission and rear ends of ALL brands, just as prior to the later 50's there was no Zinc in readily available automobile oils as it was not needed. Most of the"A"'s driving around today never had any 600W after they left the dealer and no zinc until the late 50's and they are still runnin'.

[Uncle Bob]

Originally Posted by 30blutudor

I just changed the oil in my rear end and trans to 140WT with the EP additive. Should I change back to 600W to avoid damage?

Snakes, shakes everywhere! LOL

The narrative within the Model A community is often that you'll ruin your car, I get that. While there's potential for chemical caused damage, it's not an automatic outcome. It's sort of like doctors saying high fat diets will probably kill you..............yet we all know people who have a high fat diet and live to a ripe, very old age. (but since we all die eventually the doctor is ultimately correct) But the horror stories prevail. On a similar vein, there are millions of miles/decades of satisfactory service with EP lubes in identical or similar applications. It comes down to your own peace of mind. For me it's not worth the whizzing contest to refute tribal belief.

[Tom Wesenberg]

Originally Posted by Special Coupe Frank

Suggest you buy all that they have, at that price !

I agree, the last 5 gallon pail I bought about 5 years ago cost me $80.

[Tinker]

Originally Posted by Special Coupe Frank

Suggest you buy all that they have, at that price !

Looked at the bill, I was wrong I paid $11.02 per gallon. They had 8 more 5 gallon buckets there.

[Tinker]

Originally Posted by just plain bill

I will state this again, until the restoration's started after WW2, probably 1960 ,no one was concerned about 600W oil. Most if not all automobile service stations used 90W for cars and 140W for trucks on their grease racks to replace or top up the transmission and rear ends of ALL brands, just as prior to the later 50's there was no Zinc in readily available automobile oils as it was not needed. Most of the"A"'s driving around today never had any 600W after they left the dealer and no zinc until the late 50's and they are still runnin'.

That was my bad Bill. p680 oil i believe isn't 600w. Sorry. I believe it's more like 180w. I could be wrong though. It is definitely thicker then the 90-140 oil. Haven't been able to find too much info on the web to verify though.

[Tinker]

Okay I did find this chart listing various worm gear oils. Rates the p680 at 175w.

[HoarseWhisperer]

From MAFCA website:

Question: I understand that Ford originally recommended 600 weight oil for use is the Model A steering, transmission and differential. Are the oils you now buy which are described as 600 the same as originally supplied?

Answer: It is a mystery how or why the term "600W" became synonymous with Model A steering-transmission-differential lubrication. The only reference to "600" or "600W" I can find in Model A Ford literature is on page 377 of the Service Bulletin where they are discussing the seven tooth steering system. On page 375 of the Service Bulletins they recommend M-533 lubricant for the transmission and differential whereas on page 216 the recommend simply, "gear lubricant."
So far, we have been unable to locate information which defines the characteristics of what we commonly call 600W. cone 1919 Model T literature describes it as a "Steam Cylinder Oil." Elsewhere, the 600 is defined as the flash point of a specific steam cylinder oil. I have yet to buy "600 oil" where the container provides any information as to its contents.
I would prefer using a known viscosity oil rather than an oil about which I know nothing. Rather than buy an unknown, I would recommend a quality high pressure gear lubricant for the Model A steering-transmission-differential such as SAE 250 or SAE 140 in that order. SAE 80W-90 is a little thin for quiet shifting and you will probably hear more transmission and differential noise than with 250 or 140. Some companies are packaging an 85W-140 oil which is a little thin for our purpose. -- Lyle Meek, Technical Director

[Terry, NJ]

Again, I go back to my 8N tractor days, (9N, 2N, 8N 1939-1952) The 'Generallly" approved trans,differential gear lube was GL-1 0r 2.(Hard to find) It was an early gear lube and contained no sulphur that would eat up yellow metals. I think I'm just going to buy mod A rear and trans lubricant, there's too much discussion and confusion on this subject ( all well meaning) to be sure of anything.
Terry

[Uncle Bob]

Originally Posted by Tinker

Okay I did find this chart listing various worm gear oils. Rates the p680 at 175w.

Sorry, but you're misreading the chart you attached. That 175 is a viscosity measurement in Saybolt Universal Seconds (SUS) at 210f (which in turn is an obsolete viscosiy measuring spec). In gear oil specifications there is no such grade as 175 or 175w. If you were to convert 175 SUS to a standardized gear oil viscosity grade it would be SAE 250, or more accurately the newer 190 grade (as an aside there is no w in that grade).

That is a VERY heavy grade, but as mentioned by Terry discussions on that end up being pretty pointless.

[rotorwrench]

Engine oil would be the only lube needing ZDDP and most flathead 4, 6, & 8 cylinder engines don't really have enough valve spring tension to get real worried about that.

If you research the SAE grading system you will find that it is very basic and has now been replaced by the ISO "International Standards Organization" ratings almost completely. There are 3 ISO grades of gear lubricant within each SAE gradient (90 wt, 140 wt, etc). It's going to get hard to get used to just like having to buy metric tools was.

There really aren't that many bronze/brass parts in an old Ford transmission (synchro blocking rings, the reverse idler bushing, and the countershaft thrust washers) so I don't know how long a high sulphur GL4 or 5 oil would take to do any damage to them. A banjo rear axle is all bearings so I can't think of any bronze/brass in there.
I wonder sometimes what all the fuss is about or whether it's worth worrying about at all. I'll use GL-1 on my Borg Warner overdrive units because they always put it in the maintenance manual not to use hypoid types.

The wrong oil is so much better than no oil at all.

Kerby

[Tinker]

Thanks Bob for clearing that up for me. I am far from an oil expert and it sounds like you have a good grasp of it all. Thanks again for the info everyone I feel a little smarter now.

[Uncle Bob]

Originally Posted by rotorwrench

If you research the SAE grading system you will find that it is very basic and has now been replaced by the ISO "International Standards Organization" ratings almost completely. There are 3 ISO grades of gear lubricant within each SAE gradient (90 wt, 140 wt, etc). It's going to get hard to get used to just like having to buy metric tools was.


Kerby

Kerby, you sound like someone with an open, interested mind about this sort of thing. You're partly correct, ISO standards of viscosity measuring are the industry norm, but that testing method is within the SAE gear oil specification, not a replacement of it. You might be interested in this info from Lubrizol (one of the primary lubricant additive suppliers to the entire industry regardless of the name brand on the packaging) http://www.lubrizol.com/DrivelineAdd...fications.html

Thanks Tinker

[rotorwrench]

Thanks for the info Uncle Bob. That's the first I've seen for a revision to the SAE gear lube specs. I'd much rather go with a system I can remember even though I'm slowly getting a grasp on the "new systems".

Kerby

[Special Coupe Frank]

Lubricants have been "evolutionary", just like the machinery itself.

Prior to petroleum-based lubricants, oils and greases were usually obtained from animals (Whale oil, beef tallow) or certain plants ( Castor bean ).

Systems for measuring the viscosity of lubricants have also been evolutionary... for some time, it seemed that SAE was the "ultimate" standard here in America, but there seems to be a shift towards ISO over the last 10 years.

The "heavy gear oil" used prior to the Depression was ( or was derived from )
Steam Cylinder Oil. Somewhere along the way, this became known as 600-weight or 600 W oil. The data sheets from Lubriplate, Mobil, and other mfrs seem to place "600 weight" oil somewhere around SAE 250 on the viscosity scale.

This oil is very "sticky", and tends to cling to gears, cylinder walls, slide valves and such, AND, tends to be better contained by primitive felt / leather seals...

Just for fun, ask a Model T guy about using SAE 90 / 140 in the rear-end of a Model T...

I believe the caution against using EP lubes in the Borg-Warner OD is because back in that era (1940's - 1960's ), most EP lubes had a high sulfur content, and this was bad for the "yellow metal" inside most gear-boxes of that period.

In my area, all the parts houses / lube distributors look at me like I have four heads when I ask for any gear lube heavier than SAE 140...
Really didn't expect to find 600, but I got the same blank look when I asked for SAE 250 gear oil...

When I get some extra cash, I will be ordering a 5-gallon pail of Lubriplate SPO-299.

[Uncle Bob]

Reader warning don't bother reading the rest of this if you're averse to geekish lubrication stuff. None of this is intended to embarass anyone, be argumentative, or start a war. Just trying to clarify misunderstandings that seem to persist in spite of prior efforts. All of what will be said is fact based not opinion (unless flagged as such), and in no way is all inclusive of what is known about the subject. None of this will improve your sex life (if you still have one), increase the size of your retirement account, or make your kids stop trying to move back in.

Frank makes a good point about things evolving, and in lubricants the wheel never has stopped turning. But some basics still remain the same. Viscosity is the most important characteristic of a lubricant, not the only characteristic, just the most important. Viscosity can be said to be a measure of rate of flow. If you look at any specification sheet or technical data (e.g. the link I posted above) you will NEVER see the word WEIGHT used by the professionals in reference to viscosity (in conversation they may go there for the sake of communicating with the non-professional). Most often you'll see the term GRADE used. Why? Because most viscosity grades are defined by institutions aimed at specific markets. For example, SAE is the Society of Automotive Engineers, aimed at things automotive. AGMA is the American Gear Manufacturers Assoc., and they serve the industrial gear world. ISO, International Standards Organization, doesn't serve the interests of a specific industry, but rather attempts to support systems of communication for technical data so that whereever a piece of equipment (for example) ends up, the user can find (in this discussion) a lubricant to serve the need. ASTM, American Society for Testing and Materials, is another similar organization that publishes standards so that different disciplines can work to a consistent procedure when describing a product or process. To help mentally process that, imagine the chaos if various bolt manufacturers didn't follow a standardized thread pitch. Standards are an absolute necessity in an industrialized world.

Okay, enough with the background stuff, and on to specifics related to comments in this thread.......I warned you this was geekish.

SAE still defines lubrication grades for automotive, have for approximately 100 years. Their grade numbers are mostly arbitrary, and specific to them as definitions. But the underlying methods of determining what physical viscosity underlies or defines, say an SAE 30, are based on standards published by ISO and/or ASTM. They're not exclusive, they work together for communication consistency sake.

Rant alert!!! What's with the W thing!!?? No, not the obsession with constantly demonizing a former POTUS, I mean the willy-nilly use of the letter w and the word weight. Remember the remark above about how the word weight was NEVER used by professionals? Well, most here aren't professionals so can be excused. But if your buddy was going around calling every woman he met a SLUT because he thought it was a compliment, wouldn't you want to straighten out his thinking? Well, unless you're a sadist.

I know, the notion of weight projects the idea of the thickness, and as most of you have learned, as you age your waist thickens and the scale shows you weigh more. In oils, the bigger the viscosiy number on the container the slower it pours at room temperature, ergo, the bigger the number the more it must weigh.....I get it, but it ain't weight it's viscosity, and viscosity is rate of flow, and rate implies time, not pounds/grams etc.

Back to the W thing. Most often (yep, 600w is the exception) when you see W behind a viscosity number it means WINTER not weight. You've learned that temperature affects the rate at which oils flow, generally (yes there are a few exceptions but that's outside our interests here) they get thinner as the temp goes up. So, in winter we are concerned about how well the lubricant flows, so it can do it's job, so what the w means is there is a standard measure for low temp flow. Otherwise, the standard measure for engine and gear lubes is done at 100c (metric, that International Standard thing). I'll post a chart below on viscosity cross references, and you'll note the w is only on the "lighter" grades (a concession to understanding on my part). Yup, because those are the ones that are appropriate for temps during what we define as winter. Notice on the "heavier" (I'd really prefer to say "more viscous") grades there is NO w.

Then there's that pesky 600w exception. Again, the W does NOT mean weight. As Frank correctly noted, before petroleum lubes became dominant, animal fats were (and in some cases still are) used. 600w has been around since near mid 19th century, before automobiles were common. It's original intent was as a steam cylinder oil. The additive that made it effective in the wet environment of steam was whale oil (of course now verboten). So, what might you think a W in the description of a steam cylinder oil might mean? Yes, you in the back row.....correct.....it inferred the presense of whale oil. Give yourself a gold star.

Those of us schooled in tribology (look it up, I can't do everything for you) could go on forever on this stuff......................you've heard of the futility of trying to teach a pig to dance haven't you? And for both our sakes this is enough for this post. Hopefully this will help your understanding, the one or two of you that endured this far, or maybe it was not really important. Your call. Thanks for listening.