Oil Questions: 1. Zinc, 2. Phosphorous. 3. Polymers, 4. Weight ring effect.

H.G.P. · 05-22-2006, 10:49 PM

Getting ready for another oil change. I know little about oil effects. Wondering:

1. What about Zinc content, it's signifigance, and should I be looking for it? If there an ideal oil along this line?

2. Same for Phosphorous?

3. Do polymer additives risk my engine for the sake of viscosity?

4. And lastly, for my engine rebuild (over a year ago), I used excellent OEM pistons, then honed, but not rebored cylinders, and new rings.

(a) Should I be using a heavier weight oil since I reused the cylinders?

(b) Will a heavier weight oil wear more on the new rings/old cylinders?

Thanks!

cnavarro · 06:43 AM

Here's a quick read. http://www.LNengineering.com/oil.html. I have been doing an on-going analysis of motor oils and have done a quick write-up on how my findings pertain to aircooled Porsches. It will answer your questions about zinc and phosphorus. I have the few oils that do not meet the requirements listed. I have over 30 tested and have 30 more in process of being tested.

I am also doing cross-country field testing of five different motor oils with Aircooled Technology which is going on as I type this post. You can follow their trek (and see datalogger data) at http://www.aircooledtechnology.com/crosscountry. We are testing Castrol GTX (baseline), Penn Grade Racing (the green stuff), Royal Purple, Mobil 1, and Amsoil. All 20w50 weights.

donstevens · donstevens's Garage

Zinc and phosphorousa are used as anti-waer additives is motor oil. Theoreitically more is better but of course there is alaya a point of no further return.

Is there an ideal oil for an early 911 WRT these additives. Probably but I don't know what it is. I can say that I have studied lots of oil analysis reports and one of the reasons I use Amsoil is for it's high levels of zinc and phosphorous.

Polymer additives risk your engine for the sale of viscosity? What do you mean?

Relaitive to your question about the pistons and cylinders, the honing and rings probably did more benefit than any oil can help or hurt. The new rings will grab that new surface in the bore and give you the compression you need. 20W50 is the right weight for early 911 engines anyway and will help reduce the effect of any piston slap caused by the old pistons in the ever so slightly larger bores.

CN Navarro - Are you studying oil analysis results of all of those different oils? Are I could not see that in the link. Are the driving conditions the same from test to test?

Don

cnavarro · 05-23-2006, 02:22 PM

Yeah, still in progress. We are taking samples of each oil midstream at equal intervals and then comparing them to the baselines which I have already. It might be another month or two before I have it all digested. Once I have all the oils tested, i'm going to scan the results and post them so that everyone can download them. Long story short, I was looking for minimum zinc and phosphorus and then the effect or purpose of other additives, like boron and moly and their concentrations.

As far as the driving conditions, they are not necessarily the same but there's tons of inputs on the datalogger to make heads or tails of the data. Take a look at what they have collected thus far. It's interesting, albeit conveluted until we have time to boil it down to something easy to comprehend.

randywebb · 05-23-2006, 02:50 PM

anti-waer = anti-wear, not anti-water ... (letter translation typo, not a deletion typo)

IIRC, Zn is good for extreme pressures.

donstevens · donstevens's Garage

Quote:

Originally posted by randywebb
anti-waer = anti-wear, not anti-water ... (letter translation typo, not a deletion typo)

Doh...! Thanks for catching that.

randywebb · 05-23-2006, 06:05 PM

no prob. -- some typos are worse than others... apocryphal story -- a US Navy ship meant to send a message to another ship that it had investigated something or other on the high seas and "situation unclear". Instead, it wapped the u and the n, and sent the typo "situation nuclear"...

Used in genetics class to illustrate that even small mutations can have big effects.

H.G.P. · 05-23-2006, 08:32 PM

Quote:

Originally posted by donstevens

Polymer additives risk your engine for the sale of viscosity? What do you mean?

Don

http://www.oceanstreetvideo.com/vwtech/oilviscosity.htm

H.G.P. · 05-23-2006, 08:35 PM

What opinions are of the BMW SG ? Should I stay away from it being a motorcycle oil?

http://www.ibmwr.org/otech/oilreport.html

cnavarro · 05-24-2006, 04:27 AM

BMW SG has more than enough Zinc and Phosphorus (and boron too!), but doesn't have enough calcium- it's not intended for long drain intervals. The Mobil-1 V-Twin is rated for 5,000 mi intervals in a motorcycle and it has about 5 times the amount of calcium (which is directly tied into the TBN and drain interval). I discussed motorcycle oils in my article and actually name a few (including Mobil-1 V-Twin) as suitable for aircooled Porsches. I run Mobil-1 V-Twin in my 911 and Royal Purple Max Cycle in my 912.

cnavarro · 05-24-2006, 04:31 AM

There is no need to use a straight weight oil and honestly, you shouldn't. There is lots of B.S. floating around on the internet regarding aircooled engines and synthetics too, especially from the VW guys. The only multi-grade oils you should stay away from are the 5w50 and 10w40, as they have lots of VI and tend to break down faster. You shouldn't be using a 10w40 anyways or anything lighter, so it's not a big deal.

donstevens · donstevens's Garage

Quote:

Originally posted by cnavarro
There is lots of B.S. floating around on the internet regarding aircooled engines and synthetics too, .....

The only multi-grade oils you should stay away from are the 5w50 and 10w40, as they have lots of VI and tend to break down faster. You shouldn't be using a 10w40 anyways or anything lighter, so it's not a big deal.

I agree about a lot of BS out there. There are a lot of old wives tales out there and much of the comments made are not in proper context. In the articles H.G.P. referenced for example, a quote is taken form a 1992 Buick owner's manual!. That news was old when it was printed and has little relevance today. The point is, be careful what you read and hear and if it sounds goofy, ask around. There are some knowlegable guys here and other places on the net who can help.

On the VI polymer issue - note that the article says something like "synthetics excepted". Most synthetic base stocks need less viscosity improver polymers to maintain good pumpability. As a rule of thumb a 30 point viscosity spread is OK.

Second, on the motorcycle oils, It is not going to hurt your car to run a batch or two.

If you want to experiment with some of these oils I'd suggest that you have your current favorite oil analyzed as a base line. Run some experiments with others trying to maintain the same drain inetrval and duty as the base line oil. Have those oils analyzed too and compare the results. This is what CN Navarro is doing on the tests he references.

CN - I look forward to see in more results.

Don