MGB & GT Forum

OK this has probably been discussed a ton of times but need a tad bit of input. I currently use AMSOIL Z series 20-50 and have for years. This oil has zinc. There are no oil leaks of any kind on the car and I am happy with the 20-50 synthetic. I was told that diesel engines use Zinc oil. With all the diesel pickups out there someone must be making a 20-50 synthetic that could save me some money over AMSOIL. Does anyone have any clue or suggestions?

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The brave don’t live forever
The cautious don’t live at all

Well, I wouldn't use diesel oil in a gasoline engine. Almost any oil that has the last number "50" will have adequate ZDDP for our engines. So, pretty much any of the popular synthetics (15w-50, 5w-50) have elevated ZDDP (compared to 5w-30 oil, for instance). I use the Castrol 5w-50.

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Terry Ingoldsby
terry.ingoldsby@DCExperts.com

In the US, ZDDP is banned from most oil as it damages cats. I use the special Amzoil for vintage cars, ( 20-50) which DOES have ZDDP in it. Not cheap.

The additives ( about half of what is in the can) are different between gas and diesle engines. That said, hot-rodders for years have run Shell Rotella. Just now, they buy ZDDP additive to put in it.

Let the wars begin.

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Cogito ergo sum periculoso

Here is my expert's testimony on the subject:

Bob Olree at the time was a Power Train Engineer at GM and Chairman of an oil standards body when he wrote this article:

I use Valvoline VR1 racing Dino oil with ZDDP, but I don't know if their synthetic VR1 does or not.
Rut

Edit: just checked their website and the synthetic VR1 has the same ZDDP package as the Dino oil.
Rut

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1960 Bugeye,1275, 5 speed
1970 MGB, Pale Primrose
1967 Triumph TR4a
1966 Triumph TR4a
When I went to school, they asked me what I wanted to be when I grew up. I wrote down 'happy'. They told me I didn't understand the assignment, and I told them they didn't understand life. John Lennon



Edited 1 time(s). Last edit at 2015-08-28 03:26 PM by Perdido.

Steven, thanks for a reference from a QUALIFIED source. Rare around here.

Yes, they developed replacements. As in previous threads it was discussed, when all this hub-bub started, we went to Valvoline, Red-line, Amzoil, Schrader, and Royal Purple asking what their take on all this was. They all clearly stated they had replacements then or in final testing. At that time Amzoil did not have the new "s-whatever" rating as the cost of testing was crazy. Royal Purple never did at that time. ZDDP is cheap and it worked, replacements were not.

It is not a myth that ZDDP was banned from oil in new cars because it damaged the cats. The failures I know of first hand were in vintage racing of Porches. New oil, bad cam. Back to old oil, good cam. Simple. More than one case. The test above was not in race conditions, but is a more typical ( what we have) situation.

It could likely be that in the first year or so, the new formulas were not fully worked out, so all the folklore is based on 20 year old issues.

I suggest, in a B, unless you are racing a 12,000 RPM SCCA engine, it probably makes no difference. I happen to be a strong believer in Amzoil and Red-Line so buying the Z-rod is nothing different from their standard 20-50.

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Cogito ergo sum periculoso

"Steven, thanks for a reference from a QUALIFIED source. Rare around here".

I, for one, am not sure that Bob Orlee is necessarily a "qualified" source. While I'm certainly not a petroleum engineer, my engineering background causes me to have considerable pause when I read the proffered article. For one, engineers do not write that way. I googled his name for naught. I'll wait until some other "qualified" individual 'seconds' this discussion.

I'm an electrical engineer and I found the article well written for the lay person.


It does not take an engineer to find plenty of hits on Google:

https://www.google.com/search?q=bob+olree+general+motors&ie=utf-8&oe=utf-8

Every one of those 'hits' seem to quote or parrot him stating his views. Sorry, I don't find that compelling. Of course I'm only a civil/environmental engineer. Further, since my degrees were awarded over 40 years ago, there's no way I could understand this modern technology.

12.000rpm mgb engine?
Where?

20w50 gtx 15 bucks walmart 5 qt jug.
all the zddp an MGB cam needs

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That article was co-authored by Michael L. McMillan. Together and separately with others they have authored many papers and books on the subjects of of automotive lubrication and automotive fuels. They are clearly at the top of their field.



Some examples:

https://books.google.com/books?id=24bMBQAAQBAJ&pg=SA1-PA3&lpg=SA1-PA3&dq=Michael+L.+McMillan+general+motors&source=bl&ots=wxrdAZNyTt&sig=j8WVTJRhWjAfWeJVUtInwS-mX9A&hl=en&sa=X&ved=0CCQQ6AEwAWoVChMIgc6c6ZjNxwIVwi-ICh2ZVwhD#v=onepage&q=Michael%20L.%20McMillan%20general%20motors&f=false

http://papers.sae.org/881650/

http://papers.sae.org/952347/

http://papers.sae.org/881650/


Some patents granted to Olree:

http://www.freshpatents.com/Robert-M-Olree-Troy-invdxo.php



Edited 1 time(s). Last edit at 2015-08-28 09:14 PM by Steven 67GT.

On a race track in a Grantour. De-stroke and spin like all get out.

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Cogito ergo sum periculoso

Not precisely true. It is not approved by manufacturers of modern engines for the oils recommended for those engines - typically 10w-30, 5w-30 or (these days) 0w-30. The ZDDP levels in those oils is quite low.

However, the oil manufacturers also know that the only engines that are using 50 weight oils (20w-50, 15w-50, 5w-50) are older, "classic" or flat tappet engines (without catalytic converters). And pretty much every oil of that type that I've managed to find specs for (Mobil, Castrol) all have about the same ZDDP levels that those grades of oils always had. References are tricky to find - there is a list here http://www.jalopyjournal.com/forum/threads/synthetic-motor-oils.639681/

The problem with modern oils is that they are made for modern engines - typically with roller tappets that don't require elevated amounts of ZDDP.

There is a very good paper on ZDDP that was published in a respected journal. Unfortunately, I didn't make a copy when I read it a few years ago and I can't bring myself to pay about $50 to get a copy from one of the sites that makes journal papers available (for a fee). I *think* this is the paper - http://link.springer.com/article/10.1023%2FB%3ATRIL.0000044495.26882.b5

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Terry Ingoldsby
terry.ingoldsby@DCExperts.com

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"One test is worth a thousand expert opinions"--Alvin "Tex" Johnston...Boeing test pilot.

"Who do you think you are? I am."...Pete Weber

73 MGB. Tires: Round, black, hold air. Oil: Sometimes old, sometimes new...always slippery. Oil filter: Yellow, usually full of oil. Carbs: 2 SU HIF. Distributor: Yes. Headlights: Not that bright but bright enough. A bunch of other stuff most cars have but not really important enough to itemize. Oh, wait...it has a cool sounding exhaust with stickers on the chrome tips. Really slays the ladies...

And yet at the end of the day cheap as chips 20w50 mineral oil still does the job just as well as anything else you care to spend your money on