OIL CHANGE AFTER BREAKIN

[David Jones]

But for price Swepco is as good as any on ZDDP levels. Mobil 1 V twin is another good oil but just like gasoline you can spend more money for higher octane when it is not needed and more than 1200 ppm ZDDP is overkill in a 356 engine. One could also buy any 15/40 or 20/50 and add the GM EOS additive which is rich in ZDDP.

[Brian R Adams]

I once used conventional Shell Rotella or Chevron Delo 400, but then the mandated "green" diesel fuel formulations came along and those oils seemed to necessarily lose their high ZDDP content (per my research back then.) Did I miss something?

Then I found some "4-cycle marine" oil sold by my local West Marine store which, by decoding the API codes, seemed to retain high ZDDP levels.

Now I'm using Mobil 1 15W-50 full synthetic which is marketed as having 1200 / 1300 (phosphorous / zinc) ppm.
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[Jay Darlington]

I once used conventional Shell Rotella or Chevron Delo 400, but then the mandated "green" diesel fuel formulations came along and those oils seemed to necessarily lose their high ZDDP content (per my research back then.) Did I miss something?

Then I found some "4-cycle marine" oil sold by my local West Marine store which, by decoding the API codes, seemed to retain high ZDDP levels.

Now I'm using Mobil 1 15W-50 full synthetic which is marketed as having 1200 / 1300 (phosphorous / zinc) ppm.
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just got home with mine. i exchanged my 10/30 for some 15/50, life will be good now.
Jay D.

[Brian R Adams]

just got home with mine. i exchanged my 10/30 for some 15/50, life will be good now.
Jay D.

Best price I've found is at Walmart. Harry Pellow, bless his soul, used to tout synthetic oil (against the run of play, and before ZDDP was a buzzword) pointing out that simply switching from dino to synthetic would raise idle speed significantly. He probably cited other evidence but that's all I retained.
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[Brian R Adams]

Any diesel oil of that value will have enough ZDDP. I would recommend Mobil 1 or Shell Rotella synthetic.

I found this in a Rotella FAQ. It highlights "1200 ppm of zinc" for one particular grade of Rotella - T6 5W-40 Full Synthetic Heavy Duty Diesel Engine Oil. However, the term "phosphorous" is notably absent, which in my suspicious mind leads me to believe it has been lowered below the roughly 1000 ppm level (or higher) we would hope for, else the writer would surely have pointed out phosphorus as well as zinc. Given my misgivings, I will stick with Mobil 1 15W-50 synthetic.
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Zinc is an important component in Zinc dialkyldithiophosphate (ZDDP) which forms a sacrificial anti-wear film in an engine to help protect internal components such as a camshaft. Most Shell Rotella engine oils, including T6 5W-40 Full Synthetic Heavy Duty Diesel Engine Oil, contain approximately 1200 ppm of zinc which will benefit older and high-performance engines.

https://rotella.shell.com/en_us/info-hu ... e-faq.html
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[Jay Darlington]

this is were i got some of my info. http://www.billswebspace.com/mobil_1_product_guide.pdf
Jay D.

[David Jones]

I used Mobil 1 synthetic 10/30 in my Vee race engines most of my racing years. I never suffered bearing failure or significant wear over 20 plus race weekends on each engine, but the engines were pampered, never used for short journeys and multiple starts. Just a lot of time above 6k rpm and they sometimes got very hot.
No ZDDP but of course relatively very short time between rebuilds
There is a school of thought that leans toward high flow oil lubrication rather than high pressure and belief that 10/30 will of course flow more easily. I am going to stay with more ZDDP and thicker synthetic oil for my 356 engines.

[Brian R Adams]

I used Mobil 1 synthetic 10/30 in my Vee race engines most of my racing years. I never suffered bearing failure or significant wear over 20 plus race weekends on each engine, but the engines were pampered, never used for short journeys and multiple starts. Just a lot of time above 6k rpm and they sometimes got very hot.
No ZDDP but of course relatively very short time between rebuilds

The issue mitigated by ZDDP is rapid cam wear with flat tappets. There is a very narrow contact patch under max valve spring pressure. I don't believe bearings are relevant.
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[David Jones]

You are correct Brian but in my first years racing it was common practice to change bearings after maybe 6 race weekends and re lap valves and replace rings if one wanted to stay competitive. After switching to synthetic I could go at least twice as many race weekends. Indeed one engine in my last season went over 24 races and still had good oil pressure and leakdown numbers. The ZDDP may be a large factor regarding lifters but the improvement overall in superior lubrication was the major factor. The 10/30 was not that rich in ZDDP.

[Brian R Adams]

You are correct Brian but in my first years racing it was common practice to change bearings after maybe 6 race weekends and re lap valves and replace rings if one wanted to stay competitive. After switching to synthetic I could go at least twice as many race weekends. Indeed one engine in my last season went over 24 races and still had good oil pressure and leakdown numbers. The ZDDP may be a large factor regarding lifters but the improvement overall in superior lubrication was the major factor. The 10/30 was not that rich in ZDDP.

Excellent info, David. Seems to me the modern synthetic with plenty of ZDDP is perfect for our engines. There was some hand-wringing over this some years ago.
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[Harlan Halsey]

Our 356 engines were designed for straight 30 weight oil with about 1300 ppm ZDDP. 10 weight in cold temperatures. Most engine wear takes place on start up before normal running oil pressure is established. That is why the oil is directed to the cooler only after bearing pressure is established on startup. Multi viscosity oils, say Mobil 1 15W-50, offer the low viscosity rapid flow characteristic on startup, yet retain relatively high viscosity at operating temperature. In other words, from the flow point of view, better than 30 weight on startup and better than 30 weight at running temperature. Apparently, Porsche was concerned about the lubrication efficacy of the new multi vis oils, so they delayed recommending them until after the 356 era. Since the 1970's Porsche has come around and recommended multi vis oils.
I was in the 1920s that the value of ZDDP was discovered and it was routinely added to engine oils without fanfare until the zinc component was found to shorten the life of catalytic converters. When the ZDDP was removed, and engines went to roller tappets, it was found-surprise-that the old flat tappet cams began to fail. Hence the current concern over the level of ZDDP.
Zinc is not ZDDP. The reported Zn levels are only a proxy for what we are really interested in.

[Brian R Adams]

Zinc is not ZDDP. The reported Zn levels are only a proxy for what we are really interested in.

And only a partial proxy at that, since ZDDP has a phosphorus component as well.
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[Neil Bardsley]

I think you need to consider what type of driving you do and in what temperature? Pre summer most of my driving is relatively short and the engine rarely got up to 90/100c. For this type of driving I was happy to use a 5/30 good synthetic. As most of the wear happens on startup and while the oil is still cold. Now summer is here I'm using 10/40. I have a lot more confidence it can run better at higher, extended temperatures than a mineral.

[Brian R Adams]

I think you need to consider what type of driving you do and in what temperature? Pre summer most of my driving is relatively short and the engine rarely got up to 90/100c. For this type of driving I was happy to use a 5/30 good synthetic. As most of the wear happens on startup and while the oil is still cold. Now summer is here I'm using 10/40. I have a lot more confidence it can run better at higher, extended temperatures than a mineral.

You don't worry about cam wear and low ZDDP? I don't know of a synthetic in those viscosities with enough ZDDP
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[Harlan Halsey]

+1