Doug Hillary

Hi,

This Oil Condition Report ( Used Oil Analysis - UOA ) relates to the current oil in my car and may be of interest to those who have followed the previous four reports
As noted the oil has covered 5435kms ( 3375 miles )

The oil and filter were NOT changed at this sampling point as the ExxonMobil report OK'd the oil for continued use and it will be changed at Porsche's prescribed maximum time limit

The car is now on Mobil's Delvac 1 5w-40, a Heavy Duty commercial diesel engine oil. This oil is the very latest rated diesel engine oil - API CI-4/SL - it also exceeds ACEA's A3 and B3 ( E3,4,5 & B4) and is suitable for high performance petrol engine vehicles
It has a lighter viscosity than the previous Shell Helix Ultra which was a 15w-50 grade

Details:

Oil Condition - "use" factors;

Lab. Report Summary

Elemental ( & wear metal ) Analysis;

Note:
None of the elemental wear rates are significant. All are below the previous averages and well below Industry acceptable figures.
This indicates that rings, pistons, bores, cams, bearings and other major components are wearing at a very very low rate

This is another "technical analysis" of why the 928 engine is so durable in normal use and when using the Porsche recommended ( or better ) lubricants changed at Porsche recommended servicing intervals

Oil Condition Summary:

The oil was used for 5435kms ( 3375 miles) in about one month. During this time the car was driven above 160km/h ( 100 mph ) for extended periods in 33+C temperatures

This very high quality oil will be changed according to Porsche's distance/time recommendations or earlier if a UOA determines this - which is most unlikely!

Regards

ErnestSw

Doug,
It's extremely interesting that there appears to be less wear with the Delvac than with your previous oil. I, for one, will be anxious to see whether your further analyses continue to show a statistical significance.

Doug Hillary

Hi Ernest,

yes this is a very robust oil - sadly it is not readily available at retail sites anyware worldwide. Mobil Truckstops maybe

I was amazed to see the low wear rates too considering the very hard use of the car in this period and that the virgin ( new ) Del 1 starts off with 1ppm Iron and 1 ppm Alum. content

It is very difficult to obtain Del 1 here in OZ unless you are involved in Road Transport circles

All of my heavy and light trucks and cars are now using it - I have used it in my heavy ( 500hp ) trucks since 1998 and for many millions of kms

Today here in the Tropics it is a humid & sweltering 35C

Regards

ErnestSw

I was able to order a four (US) gallon case of it for about $100.00 through the internet. Specially designated truck stops also carry it throughout the US. I haven't changed my oil as yet, but will do so within the next month.

Doug Hillary

Hi Ernest,

if you have been using a 15w-50 oil you may notice a minor drop in oil pressure at idle. This is of no account - flow is up accordingly and this oil will operate at very high and very low temperatures with ease. It has an excellent HT/HS viscosity at 150C

The highest we have seen in a truck is 112C and overall average is 103C

Your buying price is excellent - I pay $A196 for 20 litres

Regards

Brent 89-GT

I read a column in C&D once about motor oils. It was based on an interview with an oil engineer. One interesting point that came out was the better anti-wear additive packages in oils formulated for diesels. There was one additive in particular mentioned that was responsible for this. The pitfall was that long term use affected catalytic convertors negatively. Does anyone have any further insight on this?

jayc67

I'm more interested in the fact that you had sustained drives over 100 (MPH) and still managed to turn in an average of 22MPG!!!!!

I average around 17MPG on my high speed runs.

Do appreciate the oil details as well.....very interesting, although I'll admit I don't understand a lot of the chemistry.

Gretch

Who dija get it from Ernest? I want some, (mostly for my tractors)

ErnestSw

Gretch,
This is not the place from which I ordered mine, but it's around the same price.

http://shop.store.yahoo.com/avlube/ffasicofaarh.html

Doug Hillary

Hi,
Brent 89GT
Yes, even diesel engine oils "ain't oils" - the anti wear additive is zinc ( well, ZDDP ). The synthetic base's blend is significant in anti wear too - in this case it includes Alkyl Esters
( Note: we stopped adjusting cam valve/injector actuators in 1999 on our Detroit Diesels due to the low wear rates over 000 000's kms with this oil )

As long as the oil is specced with an API petrol oil rating included ( Del 1 is CI-4/SL ) and that rating is at least SH> all is well for the catalyst. The diesel rating being above CG helps too

jayc67
The fuel economy simply amazes me too. A look at the engines "fuel curve" in the owner's handbook confirms that the "sweet spot" is at about 3000rpm and long periods were spent near there. Don't tell the OZ Coppers please!

On this particular trip there are very long stretches of flat desert like roads and very little traffic - and cruise control helps. Somes parts of journey were just the opposite however and we travelled in a 928 convoy for about 250 miles as well ( great fun )
The car was fully loaded ( heavy ) at all times

The transmission and diff are both on synthetic ATF/oil too which helps a little too I suppose

Understanding the oil's chemistry is NOT all that important really to the end user, but hopefully this all helps us to realise that technology has come a long way - even with lubricants. And to understand our 928s better

The oil testing regime ( UOA ) has been around for decades - Caterpillar have based there maintenance practices on it for decades - and even these standards are now very reliable and able to be replicated worldwide

Amazingly, I recently had some oil from an engine in the USA analysed by "Signum Oil Analysis Lab." under contract - the World is a small place!

Regards

Jim bailey - 928 International

Once again Doug has proven that IF you change oil at 3,500 miles .....the oil you are draining is as good as the new oil you are paying to put in !!! The only one to benefit is the shop selling you the oil change .........once a year or 15,000 miles is being " good " to your car ........