What kind of oil should I use / what is the "best" oil?

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Edwin Ek
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Re: What kind of oil should I use / what is the "best" oil?

#76 Post by Edwin Ek »

Very jazzy description on Porsche's website, but no mention of ZDDP levels.
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Gordon Maltby
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Re: What kind of oil should I use / what is the "best" oil?

#77 Post by Gordon Maltby »

George Dunn and I met with Porsche Classic people in Germany in April when they rolled out the new oil. The first question we had was whether it had zinc and how much. Curiously, they were not able to answer the question then or in a subsequent email. I think they got the message that owners really wanted to know, so two days ago this press release indicated it had zinc and phosphorus:

Porsche Classic Motor Oil comes in two different versions:
• 20W-50 for all 356, 914, and 911 models up to the 2.7-liter G-model
• 10W-60 for flat-six engines of 3.0 liters and larger.

Porsche Classic Motor Oil offers the following benefits:
• Specially developed for Porsche air-cooled engines
• Tested in the lab and on the road by Porsche AG
• Compatibility with the alloys and sealing materials used in the air-cooled engines
• Excellent high temperature resilience and shear stability
• Optimum protection against wear and corrosion provided by zinc and phosphorus
• Engineered by Porsche
 

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Wil Mittelbach
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Re: What kind of oil should I use / what is the "best" oil?

#78 Post by Wil Mittelbach »

Gordon -
It would be of much interest to compare Porsche's 20w-50 oil's Zn/P "anti-scuffing" content to the 356 oils we use - such as Brad Penn, others, etc.

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Harlan Halsey
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Re: What kind of oil should I use / what is the "best" oil?

#79 Post by Harlan Halsey »

356 Street engines are not very sensitive to the oil you use. Originally Porsche specified single weight oils. Then, only long after Americans had gone to multi weight oils, Porsche followed. Back in the 1960's In Massachusetts I used Quaker State 20W-40 exclusively and changed it every 2000 miles. When I disassembled that 3656B 1600S engine at 95,000 miles, the crank measured on the high side of factory spec. That engine is still running with about 180,000 miles on it. When QS became impossible to find, I switched to Kendall 20W-50. I ran Kendall straight 40Weight in my Carrera until one day in the 1990s, I noticed that Kendall was no longer green. I checked the part number. It was unchanged. It turned out that Conoco Phillips had bought the Kendall name, but not the refinery, and was selling their own oil as Kendall! About this time the ZDDP scare happened. It turned out that oil companies were reducing the ZDDP content of oils thinner than 40Wt. because those thinner oils were what the current car manufacturers were designing to in order to increase the gas mileage. The ZDDP was a side effect in that the phosphorus or zinc was damaging the catalytic converters, making it difficult to meet the US Govt. requirement that the converters go 50,000 miles. For a long time the ZDDP content had been 1300ppm, but with the API SM oils, the ZDDP content was reduced to about 800ppm only for oils thinner than 40 wt. which we don't use in 356's anyway.

Meanwhile, some employees of the original Kendall refinery restarted it under the Brad Penn name, with the 1300ppm ZDDP content. SWEPCO also markets a high ZDDP content 15W-50. And I think that Mobil 1 in the 15W-50 weight has 1300ppm ZDDP. (BTW ZDDP is a trick molecule which provides lubrication in high pressure situations such as between cam and follower. Roller followers don't need it.)

Since we have at least three fully adequate high quality long tested engine oil alternatives at about half the price, and last I heard Porsche doesn't own any oil refineries, why would anybody buy the Porsche branded stuff?
Last edited by Harlan Halsey on Wed Jul 30, 2014 7:17 pm, edited 1 time in total.

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Brian R Adams
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Re: What kind of oil should I use / what is the "best" oil?

#80 Post by Brian R Adams »

Harlan,

The ZDDP figures should be 1300 ppm (not 13 ppm) etc.

Also, I believe you are mistaken in thinking any oil 40-wt or heavier was exempt from the ZDDP reduction. Could you cite a reference to back up that assertion?

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Harlan Halsey
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Re: What kind of oil should I use / what is the "best" oil?

#81 Post by Harlan Halsey »

You're right Brian, 1300 ppm, not 13. And 800 not 8. What was I typing?

My source was private communication from a Jim Shannon of the American Refining Group. The reason he gave was the one cited above, that new cars don't use 40 and 50 Wt. oils. (Diesels however, require ZDDP because of high piston pin loading hence our interest in using Diesel oils.) He said" the primary viscosities involved in these PCMO [Passenger Car Motor Oil] categories are the lower muli-vis formulations e.g. SAE 5W-20, 5W-3,and 10W-30. This is due to the fact that they fall under the ILSAC energy conserving viscosity guidelines and are also the viscosities recommended in the OEMs owners manuals."

That was a while ago, today, ZDDP content data is much more available, but what he said still makes sense to me, otherwise how would any company be able to offer a high ZDDP content PCMO oil in the USA?

Now, weather they do or not depends on their marketing strategy. But we can no longer rely on the API to specify good oils for us. The API is only interested in high volume modern car production. Unfortunately our interest has diverged from the mainstream.

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Re: What kind of oil should I use / what is the "best" oil?

#82 Post by Brian R Adams »

Harlan,

I may not understand just what you are referring to. When you say "40 wt" oil, does that mean straight 40 viscosity only, or, say 15w-40 multi-viscosity as well?

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Harlan Halsey
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Re: What kind of oil should I use / what is the "best" oil?

#83 Post by Harlan Halsey »

Brian,
multi-vis: xxW-40, xxW-50, etc. There may be someone out there but I doubt that many 356 owners are using single weight oils anymore. However if you want to be correct, and win the concours, the 1964 C Drivers Manual states: SAE 40 for more than 85F, SAE 30 up to 85F, SAE 20 up to -5F,and SAE 10 below -5F. the 1967 912 Drivers manual states: summer SAE 30, winter SAE 20. Nothing about multi-viscosity oils.

Back then the received lore was that most engine wear took place on startup as the pump was beginning to circulate the oil and before oil pressure had built up. The single weight oils of the time had a relatively steep viscosity vs. temperature relationship. (They got thin with increasing temperature fast.) So you wanted a thin oil for rapid flow on start up but needed a thick oil at running temperature. Hence the compromises suggested in the Drivers Manuals. In the late 1950's the oil companies came to the rescue with additives which flattened the viscosity vs temperature relationship. A 15W-50 is as thin as a single weight 15 oil when cool and as thick as a 50 oil when hot. Apparently, Porsche didn't believe that the new multi-vis oils lubricated as well as the old single weight oils for a decade or so. But by 1964 I and everybody I knew was using the multi-vis oil. Quaker State 20W-40 in street cars. We still used single weight oil in the racing cars and I still do in the Carrera.

Today, here in California where it never gets cold, I use a 15W-50 with at least 1000ppm ZDDP, for as long as I can get it. But I suggest that you contact your oil supplier directly if you are concerned about ZDDP levels

BTW there is a spec which I have never seen, but would like to, and that is the rate at which engine oil runs off steel surfaces. I think it was Paul Christensen who suggested that the synthetics may run off, that is not stick, as well as the non synthetics. If so this would be good to know for a car which may sit for a while.

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Re: What kind of oil should I use / what is the "best" oil?

#84 Post by Norm Miller »

This is stressing my memory but, when racing in the 50's & 60's we didn't have multivis oil.
When it became available we were very suspicious + it was only in 10W-30, not good for racing.
When we got over the bean oil trend we went to Valvoline Racing (50w ?).
Castrol dinosaur oil had a tendency to foam.

Someone correct my dates. David?

Norm
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Brian R Adams
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Re: What kind of oil should I use / what is the "best" oil?

#85 Post by Brian R Adams »

There was a list of most (then) current oils floating around here, prepared by Charles Navarro, and there were many 40 and 50-wt oils which had reduced ZDDP levels.

Then word got around to the manufacturers, and a few products started being (re-)formulated and marketed specifically to address this niche, e.g. Catrol's 20W-50 "for older cars". But it was never true, and I don't believe it is today, that all 40 and 50-wt oils have high ZDDP levels.

Also FWIW, the desired level of ZDDP (according to Navarro and many others) is ~1200 PPM, so 1000 ppm is marginal (assuming the metrics really are critical) but 1000 is better than 700.

Brian
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Re: What kind of oil should I use / what is the "best" oil?

#86 Post by Ken King »

Brian, some time ago you mentioned that Mobil 1 had great levels of zinc and phosphorus, but was more expensive than other dino alternatives. I am at a point where I need to order another box of Brad Penn, at about the same price as the synthetic (and 1/3 the price of the Porsche oil). And all I have to do is drive over to Wal-Mart for a 5 quart jug. Given all the advantages of synthetic oil, with leakage being the only disadvantage that I can think of, I am sorely tempted to try the Mobil 1 15W-50. I don't like to be changing the type of oil I use, but I have to wonder if it wouldn't be worth it. Given that this whole discussion seems to come down to these two alternatives, (plus perhaps a Castrol motorcycle version synthetic?), I would like to see some clarification regarding synthetics. Some say never use a synthetic in these old engines, some say do. One concern I have with Brad Penn is that it never seems to look very dirty. I personally believe that modern technology probably provides a more reliable product, with higher film strength, than older oil, even one as good as Brad Penn (which has some synthetic in it, if I remember correctly).
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Re: What kind of oil should I use / what is the "best" oil?

#87 Post by Edwin Ek »

I think it is more than "received lore" that most of the wear happens at startup. Three factors: all of the oil has drained into the sump, so the engine starts relatively dry, the oil is more viscous when cold, so it doesn't flow as quickly or easily, and the richer mixture to aid starting means more unburned gasoline washes down the cylinder walls.
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Re: What kind of oil should I use / what is the "best" oil?

#88 Post by Jeffrey Leeds »

Ken, you might also consider Mobil 1 V-Twin, (20W-50) which is a motorcycle oil with nominal levels of Phosphorus of 1600 PPM and ZDDP of 1750 PPM. This is readily available through Amazon and many local FLAPS at competitive prices.

Neil Fennessey, our resident academic for matters such as this, recommended this oil to me several years ago, and supplied me with some from his own stash, when I found myself at the bottom of my dip stick at Lime Rock, and it has worked well for me.

Also Porsche Classic has "determined" that 20W-50 is the "appropriate" mix for air-cooled pre-'89 engines, and this fits that parameter as well.
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Brian R Adams
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Re: What kind of oil should I use / what is the "best" oil?

#89 Post by Brian R Adams »

Edwin Ek wrote:all of the oil has drained into the sump
Most, but not all (of course).

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Re: What kind of oil should I use / what is the "best" oil?

#90 Post by Frank Leonetti »

I posted a question about old motor oil and see there was much previous discussion about using it now even though it was correct viscosity and would contain high ZDDP levels. Some members said throw it out and others said "send it to me" indicating that they would use it. I have many quarts but don't think it is worth the risk to use it.
There are many current oils recommended for our engines-Brad Penn, etc. Brian Adams mentioned West Marine oil.
Brian, do you still use/recommend West Marine? There is a West Marine near me but I can't find any info about its ZDDP content.
Thanks and thanks to all for your info, experience and research that benefits all of us.
FALeonetti

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