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