MANUAL

Gidday Doug,

Thank you for sharing your experience and helping me understand the complexity of engine oil.

1) On the occasional 4.5%, why did you choose to exceed Mobil's limit of 3.5%?

2) What is the approx. weight penalty for installing the centrifuge cleaner? Are you aware of any diesel cars that have had the cleaner installed?

3) How did you know the FF filters were completely clean at 100k kms ? Were you "eyeballing" it or did you have a UFA done?

4) Even though it's not "Porsche Approved," using Delvac 1 5w-40 in a CGT that lives in an area above -15 C may not be horrible, eh?

5) In your experience, has Delvac 1 5w-40 ever been a primary cause of either petrol/gasoline or diesel engine accelerated wear and/or failure?

6) When the Benz Kompressor oil temperature is significantly higher than the 928, would not Delvac 1 5w-40, with its higher than M1 0w-40 HTHS, be all the more suited for it? As you point out, it has not been approved by Benz but are not the odds more likely that it would protect rather than harm the engine?

7) By "short run," do you mean his trips are less than the approx. 30 minutes needed to warm up oil?

8) Did you seek advice from Porsche and Mobil Engineers before using Delvac 1 5w-40 in your 928? Or was it unnecessary to seek advice since your 928 is operated under "general use?"

Doug Hillary

Hi Manual,
here are the answers and comments in your order;

1 - I had "inside" knowledge that up to 6% soot loading had not shown to be detrimental due to the way the additive package and base lubricant tolerated/handled it (soot)

I have/had a fair bit to do with Oil and Engine Company Engineers, and with Additive suppliers over many years. In the case of Delvac 1 5w-40, I monitored the performance of this lubricant for about four years prior to changing from Castrol's excellent semi-synthetic diesel engine oil (Enduro LD) which I helped to develop
My engines cost around $45000 each so knowledge, respect and care is paramount!

Over many millions of kms (and on many engines) the average oil change interval was 90kkms (56k miles) and the average soot loading was 3.23% at the oil change point.
Average oil consumption was around 6kkms (3.7k miles) per litre during the oil use cycle

2 - The MANN-Hummel FM060 centrifuge I used (for engines 150-750kW) weighs about 7kg installed
The Land Rover (2.5 TDI) has a disposable centrifuge as OE and a few others from other Manufacturers do too I believe. Many years ago a number of French car makers fitted them as standard to petrol engines too

The lightest car version weighs about 2kg installed I believe

3 - At each oil change my staff cut the top off each FF filter (using a special debris free cutter) and dissected the filter's filtration media. I then inspected this - I have had a lot of experience in this area with Euro, Japanese and American engines. We did not do a UFA.

We carried out a particle count on the centrifuge's compacted debris during the first half million kms or so and on a number of engines. Then, we relied on the PQ Index and wear metals data which proved to be incredibly accurate at the "tear down and inspect" point

4 - You are correct - not "horrible" at all. I believe that it would probably do the job very well indeed

I use this oil in a wide variety of petrol and diesel engines (Korean, Japanese, American and Euro) where it meets the viscosity/engine requirements

5 - No. The oil has always shown up as a very good lubricant. Additionally, a variety of data on BITOG will confirm this comment
At an engine (my engine) tear down inspection after using this lubricant, all wearing parts were still within re-usable tolerances after 1m kms (620k miles). Cross hatch patterns were visible on each liner's wear surface. The engine was taken apart/measured up/reassembled by the engine Manufacturer's personnel

6 - Yes, I would like to use Delvac 1 5w-40 in the Kompressor but for at least the first year of the Warranty period I will stay with M1 0w-40.
The higher HTHS viscosity of Delvac 1 is not that important in this engine
What is important is the oil's flow, and up to about 80C M1 0w-40 is better than Delvac 1 5w-40. In fact up to about 50C oil temperature, M1 is substantially less viscous
Some engines can be noisy for a few seconds at cold start up when using M1 0w-40. Whilst it is inconsequential this can be disconcerting for some people. My Subaru Outback 2.5 and BMW Z3 2.8 displayed this characteristic and both were changed to Delvac 1

7 - Yes. A E Haas I believe is mindful of that and of his costly technologies too. Most users are not so caring and the "law of averages" must take precedence in general use with the general public. Some vehicle owners go from a cold start to 6000rpm and with heavy engine loads without a second thought - shudder!

8 - I sought no advice from Porsche when commencing to use Delvac 1 several years ago. After some years of use in a variety of engines I was very confident that the lubricant offered much more than the (928) engine needs.
Some Mobil Lubricant Engineering personnel said "Why don't you simply use M1 0w-40" or such.

It is interesting to note that this is now a Mobil recommended lubricant for all 4, 6 and 8cyl Porsche engines built since 1973!

Of course UOAs have been a part of my use of any lubricant over many years. And, always with the full knowledge and co-operation of the Oil Company Engineering and Laboratory personnel involved

Sadly advice from some Workshop and Service Provider personnel is not always accurate!

I stress again that I have no allegiance to any Oil Company in any way whatsoever

Regards
Doug

MANUAL

Greetings Sir Doug Hillary,

1) In the case of this Benz engine, how do you know better cold oil flow of M1 0w-40 is more important for it than the D1 5w-40's higher HTHS viscosity? Another example of "inside" knowledge?

2) Is this engine less noisy at cold start-up when using M1 0w-40 versus D1 5w-40?

After reading many of your posts, I am convinced.

Doug Hillary

Hi Manual,
some data;

Your No 1
In most Euro engines designed in the last decade or so an oil with superior and linear cold flow characteristics is required - for reasons mentioned earlier. This Benz engine family is but one, and yes a little inside knowledge helps for sure!

The following chart gives the approximate viscosities of both M1 0w-40 and Delvac 1 5w-40 (CI4+/SL version);

OIL: Mobil 1, Delvac 1
VISCOSITY: 0w-40, 5w-40 (CI-4+/SL)
VI: 187, 151
Pour point: -54C, -45C
Vis 40C: 80, 102
Vis 100C: 14.30, 14.80

TEMPERATURES:
5C: 438, 737
10C: 328, 528
15C: 249, 380
20C: 193, 282
25C: 152, 213
30C: 121, 164
40C: 80, 102
60C: 40, 46
80C: 22.7, 24.6
90C: 17.8, 18.8
95C: 15.9, 16.6
100C: 14.3, 14.8

Your No 2
Only M1 0w-40 has been used in both of my new Benz Kompressor engines. I suspect that they would be quieter at startup on the more viscous lubricant. It only lasts a couple of seconds at the most.
A new TI diesel Benz I have is also noisy at startup on Delvac 1, it also takes about 5 or so seconds to get OP up. This is a characteristic of this engine family which is well known for an incredibly long engine life
The 928S4's engine is quiet at startup on Delvac 1 and has never had M1 0w-40 in it

Regards
Doug

MANUAL

Doug,

Thank you very much for the data showing the superior, linear cold flow of M1 0w-40 to D1 5w-40. I did not know linearity of viscosity change is also a factor.

Since the Benz engine is:

a) designed in the last decade or so
b) requires an oil with superior, linear cold flow,
c) the higher HTHS viscosity of Delvac 1 is not that important in this engine despite the fact that oil temperatures reach near 140C at certain points in the engine,

why do you plan to use M1 0w-40 for at least the first year of the warranty period and then switch to D1 5w-40 later on? Should you not use M1 0W-40 past the warranty period?

Doug Hillary

Hi Manual,
I intend to stay with M1 0w-40 because of the need to use a MB Approved (MB 229.5) oil during the Warranty period (3 years-unlimited distance)
These engines use a special (fleece) oil filter element that requires the use of this Approved lubricant (flow etc. related)

I may not change the Kompressor engines to Delvac 1 5w-40 at all. A previous one I owned was sold at 80Kkms (still under Warranty) and had been on M1 0w-40 from new

Note: many people do not understand that oil flows through the filtration media and will not be complete until the oil WILL flow through it. Differential by-pass will occur according to the type of filtration media, internal/external by-pass structure, oil temperature and the oil used (related)

An example: at 1bar and when using synthetic filtration media and the same oil, flow through the fitration media media commences around 5C (oil temp) compared to 22C (oil temp) when using cellulose media. The extra filtering time may have a significant affect on engine wear, as typically, most wear occurs before the oil's anti-wear additives become effective somewhere around 60C (oil temp)

The move towards synthetic filtration media will mean that the engine Manufacturer's Approved and Listed oils will increasingly become mandatory. It is already this way with heavy diesels sold here in OZ

The Benz diesel engine will remain on Delvac 1 5w-40 (MB 228.5) until it is sold at the end of its life with me

No Brand of lubricant has been shown to offer significantly better wear characteristics when compared to another with the same API/ACEA and engine Manufacturer specification

Regards
Doug

MANUAL

Hi Doug,

I am trying to understand the relative importance of HTHS.

Why do Audi and Porsche require a minimum HTHS of 3.5 while Ford and Honda say 2.6 is sufficient for some of their lower HP/Liter cars? Is it due to major differences in design, manufacturing, and definition of significant wear?

Does any correlation exist between minimum HTHS and Hp/Liter?

Fwiw, the USA Mobil website recommends either mineral/synthetic 5w-20 for the USA '06 Civic Si when the owner's manual, if I recall correctly, only recommends 5w-30. I am not aware of a mineral/synthethic Mobil 5w-20 oil with a HTHS of higher than 2.6, so it seems the website can give wrong advice.

Doug Hillary

Hi Manual,
High Temperature High Shear (HTHS) viscosity has received a lot of attention over the last several years from engine designers and oil companies. As fuel efficiencies dominate future designs (internationally) engines become more complex which in turn places a greater emphasis on secondary systems such as lubrication

As well and as a result a better understanding of the principles of both temporary and permanent shear is being addressed. This is being aided by the use of more advanced testing technologies such as real time wear measurement using radioactive tracers and etc

The ACEA has these comments concerning HTHS viscosity:
(A1/B1 quality rating)"Oils intended for use in gasoline and car/light van diesel engines specifically designed to be capable of using low friction low viscosity oils with a HTHS viscosity of 2.6 to 3.5mPas.s. These oils may be unsuitable for use in some engines. Consult owner manual or handbook if in doubt"

and,

(A5/B5 quality rating)" Stable, stay in grade oil intended for use at extended drain intervals in high performance gasoline and car/light van diesel engines designed to be capable of using low friction low viscosity oils with a HTHS viscosity of 2.9 to 3.5mPas. These oils may be unsuitable for use in some engines. Consult owner manual or handbook if in doubt"

The latest catalyst compatible quality ratings under ACEA ("C1,2 and 3) with the HTHS viscosity above 2.9mPas are another matter as well. These are known as the low SAPS oils ("SAPS" is Sulfated Ash, Phosphorus and Sulfur) and are mandatory now in some engine families

NOTE: Anybody using an HDEO in a petrol engine ((911/912 etc) should ensure that it is diesel/petrol rated (say CI-4/SL). Some diesel only rated HDEOs have very high sulfated ash levels. These deposits can cause accelerated wear in some engines

So you can see from this that your comment regarding "design" is most relevant.

Euro manufacturers have long used the higher HTHS viscosity (>3.5mPas) rated A3/B3 and A3/B4 quality ratings for their engines. There are many and varied reasons for this that would take too much time to suitably cover here. But of course they do include the wiping loads on camshafts, lining, ring and combustion chamber design and the hydraulic function of the lubricant to name but a few

Any relationship of HTHS viscosity to HP/Litre output would be mainly circumstantial I expect and I know of no specific research done on that issue
Usually a turbocharged engine is more demanding than a NA or Supercharged engine on certain aspects of its lubricant's performance. Again design and application play a huge role!
M1 0w-40 which has a HTHS viscosity of 3.6cSt is used as factory fill in AMG and Porsche engines - some NA, some supercharged and some turbocharged. It is also suitable and recommended for use in many high performance diesel engines

I believe that the Euro and other engine manufacturer's research has shown that the HTHS viscosity of 3.5cSt is suitable in a wide range of engine families. (The minimum HTHS viscosity for 15w-40 HDEOs is 3.7cSt).
Above about 4cSt the higher HTHS viscosity begins to affect the rate of frictional losses

Below a HTHS viscosity of about 3cSt, significant wear may occur when such lubricants are used in unsuitable applications. Where Ford & Honda etc seek an HTHS viscosity of 2.6cSt they (apparently) have not had any exceptional engine or component wear issues

Remember that the oil film's strength is not dependent on oil pressure. In the crankshaft's (and other Journal type) bearings area for instance the "oil dam" affect occurs in front of the journal and pressures here reach way beyond that generated by the lubrication system's oil pump. This is why oil flow is so important - the more linear the oil's flow characteristics (with full synthetics) the better the flow rate and the oil's cooling potential!

At present a lot of design and development is being done on such things as;
a) lowering the HTHS viscosity of lubricants for high output high speed diesel engines,
b) the use of advanced actuation devices (valves and etc),
c) measuring oil conservation/extended drain requirements (oil formulations, filtration on board oil conditioning devices, on board oil condition monitoring packages) and etc
d) advanced metallurgy and engine components durability testing

Low viscosity SAE 10, 20 and 30 monograde lubricants were very popular in the 1930s and well into the 1970s. Their return as short viscosity span (say 0w-20) multigrades is now primarily driven to reduce internal friction thereby improving fuel efficiency.

As for your comments regarding Mobil and the Honda Civic I can only relate this information.

To my knowledge Mobil only make a mineral 5w-20 oil and its structure is unknown to me as these are not sold here in Australia

M1 0w-20 has a HTHS viscosity of 2.61, 40C viscosity of 43 and @ 100C, 8.4.
M1 0w-30 has a HTHS viscosity of 2.99, 40C viscosity of 53 and @ 100C, 10.3
M1 5w-30 has a HTHS viscosity of 3.08, 40C viscosity of 53 and @ 100C, 10.8.
M1 10w-30 has a HTHS viscosity of 3.17, 40C viscosity of 62 and @ 100C,10

Note the relatively big variance at 40C between the 0w20 and the 10w-30 viscosities

Group 3 (semi-synthetics) and Group 4 synthetics will typically have a more robust base structure than a mineral equivalent but the HTHS viscosity may only be slightly higher enabling the fuel efficiency CAFÉ ratings. Many Group 3 lubricants are being formulated as low SAPS cost effective products and performing very well indeed

The issue of lubricants is very complex today. I have always advocated following the engine maker's recommendations. Specialists and Tribology "experts" can of course afford to be perhaps a little more adventurous in the lubricant selection

NOTE: "ACEA" is the abbreviation used for the Euro vehicle and engine makers consultative body

As for inaccuracies on websites, there are many. The Oil Industry is certainly not immune to errors at that level. The Driver's manual is always a great reference point

I hope this is of some interest

Regards
Doug

W8MM

Wow, Doug. Your post was FABULOUS! It was way more than just "interesting"!

I just learned more about motor oil by reading your posts than I have learned in the past 30 years from other means.

Thanks ever so much for taking the time to tell us.

MANUAL

Hi Doug,

I understand HTHS a bit better now, thanks.

As for the structure of Mobil mineral 5w-20 sold in the USA, a member of BITOG with inside information said that Mobil Clean 5000 5w-20, 5w-30, 10w-30, 10w-40 marketed as conventional/mineral oil is actually their mineral/semi-synthethic Group III base oil with a dash of Group I in the additive package making it more cost effective from Mobil's manufacturing standpoint and a bargain for shrewd consumers.

http://theoildrop.server101.com/ubb/...=008351#000000

Questions:

1) How much of a safety margin do manufacturers place in the recommended oil change intervals (OCI) ? Between 1978 and 1995, the 928 engines ranged from 4.5 L to 5.4 L. Did the 928 oil change intervals ever change? I am trying to understand how Honda, five years ago, was able to reduce sump capacity by 10.5% yet increase the normal/severe OCI by 33.3%.

2) If an automobile has no oil temperature gauge and it is estimated that an engine takes between 15-30 minutes to reach operating temperature, what conditions determine this range? Is it dependent on engine design, viscosity, average engine r.p.m., load, ambient temperature or combination of these and other factors?

3) Can an automobile that is idling in the driveway for 15 minutes reach the same temperature as one that has been on the move for the same amount of time?

4) What is the best way, if any, to speed up oil warm-up time while avoiding significant engine wear?

5) Must a driver wait for complete oil warm-up before redlining the engine to avoid significant wear?

Doug Hillary

Hi Manual,
the link to BITOG confirms some points already covered in here, namely;

a) always use a lubricant that is Approved & Listed by the engine manufacturer
b) lubricants having the same ACEA or API Approvals and Certification will perform primarily the same when being used in their intended application. Any variances will be at the margins
c) Some modern Group 3 "hydro-cracked" semi-synthetic lubricants now equal and maybe even exceed the performance of older formulation fully synthetic lubricants - at a lower price too

In response to your "points", my comments are as follows;
1 - Any safety margin will probably be kept confidential and "in-house" but generally <40-50% margin is probable
The 928 engine family retained the same OCIs from 1978 but some things happened en route to the end of production;
d) oil specifications were updated each MY
e) the engine's lubrication system was updated and these were technology and user driven
f) from MY92 a synthetic oil (Group 3) was used as a factory fill. For the first year this was a 10w-30 Shell product (first year) and then its viscosity was changed to 5w-40 until the end of production.

New lubricant formulations and the ever advancing engine technologies will have had a prime influence on Honda's decision making. Filtration media has improved too in recent years. Lubricants were under utilised in most new cars over the last decade or so, especially in NA

2 - After a cold start, oil temperature typically trails coolant temperature by about 10-20C until their operating equilibrium is reached
Many conditions determine this relationship and your "combination" touches on many of them. IMHO engine design is the prime "uncontrollable" factor and engine load plays the greatest role in an operational sense. Cold start ambient temperature is a significant factor too

3 - The short answer is no! Loading the engine significantly raises the oil's temperature at a faster rate than idling it
A brief test several years ago on my 928 showed that after an 8min idle period the oil's temperature was only 51C. Anti-wear (AW) additives typically become progressively active at temperatures 10C or so above that

My Professional Driver Trainer schooled each of my Linehaul Truck Drivers on these points amongst others at induction;
a) Start engine, monitor OP, AP and Voltage. Once AP was correct move off - usually after about 1-2 minutes. Monitor that the rise in coolant temperature is normal. Never allow engine to "lug" or take it beyond 1500rpm until the engine's coolant temperature is at normal point
b) With a hot engine, never allow engine to idle beyond 1 minute or only until the pyrometer is at 300C, whichever occurs first. (This was monitored off the engine's ECM)

Persons that could not follow these operating instructions were encouraged to move on!

4 - Set a personal maximum revs limit at about 50% of engine's red line until the engine has reached normal coolant temperature or preferably until oil pressure assumes the hot idle position.
Lightly load the engine by accelerating in higher gears until the temperatures are correct

5 - IMHO YES!

I hope this is of interest

Regards
Doug Hillary

928saregreat

Hey guys, great thread, lots of information. Just a couple of things I'd like to mention. There is government pressure on automobile manufacturers to reduce the maintenace interval between oil changes for environmental reasons. This isn't unique to Porsche. I'm not too familiar with Porsche the company but with other manufacturers the marketing department has way too much influence on the maintenace of new vehicles which leads to some pretty far-fetched claims regarding engine, transmission, and gear oil life at the expense of the customer. One other point I'd like to make is that it's carbon from the gasoline that we use thats reponsible for most of the engine deposits, not "oil breakdown" as the media would like you to believe. Modern oils, especially synthetics are unbelievably tough. There are very few applications that can break them down, however the oil additives in them do get used up chasing these carbon deposits and the oil filters run out of space to put it all. In my work I've seen personally a number of modern engines with less than 100k following modern oil change recommendations torn down prematurely and found to be full of deposits. I think a little common sense should prevail and It might be helpful check an number of sources as to how often oil should be changed, and not just the manufacturer of the vehicle. You can check with the company who makes the oil for example and find out what they recommend. Talk to people who race them, ect. That way you can make an informed choice.

charlieXS

fascinating discussion... also interesting to see concern for the price of a CGT oil change from CGT owners. I mean after all... in proportion to the cost of the vehicle, if my Cayenne oil change cost $30 I wouldn't think twice about it...

Fogey1

Doug Hillary (May the Porsche Gods smile upon him) wrote:
"My Professional Driver Trainer schooled each of my Linehaul Truck Drivers on these points amongst others at induction;
a) Start engine, monitor OP, AP and Voltage. Once AP was correct move off - usually after about 1-2 minutes. Monitor that the rise in coolant temperature is normal. Never allow engine to "lug" or take it beyond 1500rpm until the engine's coolant temperature is at normal point
b) With a hot engine, never allow engine to idle beyond 1 minute or only until the pyrometer is at 300C, whichever occurs first. (This was monitored off the engine's ECM)

I have a few questions:

1) What is "AP" that must be correct? (OP = Oil Pressure, I presume)

2) Never allow a hot engine to idle beyond one minute? Am I misunderstanding something - no idling seems strange to me, given the idling big rigs filling truck stops across the country. Is that just for your trucks or does that apply to cars, as well? Hmmm ... pyrometer ... maybe the AP mentioned above?

3) Earlier in this (?) thread you mentioned the Camry V-6 as a "high shear" engine. (Lexus, too, I presume) So what does that mean for oil weight and OCI in those engines?

Doug Hillary

Hi Fogey,
info as requested;

1 - "AP" is for Air Pressure (for brakes/suspension etc)

2 - Idling is a particularly bad practice with diesels and can to increased oil contamination (especially with high sulphur fuels). It can lead to increased bore/ring wear in some cases too.
As well, it is particularly wasteful of fuel (around $1.40 per litre
here). Idling is also noisy and odourous at a client's premises - most ban it
Idle time settings are available too via the engines ECM - we prefer to "educate" the Drivers as I write the cheques
Idling time as a percentage of engine "on" time is but one report available off the engine's ECM
Such things as time spent in top gear and etc is great information that we use in Driver management and Education
The Pyrometer shows exhaust temperature - this is a quick record of the engine's current load factor

I found that when a truck enters a yard/clients premises it usually takes a minute or two of light engine load while "positioning" into a dock/park. This is enough time to ensure the turbo has slowed down and cooled somewhat

I believe that excessive idling should be avaided in cars - when an engine is turbocharged a 30 seconds to a minute idling at shut down is probably a good practice. This is especially so after driving hard/climbing and then pulling into a roiadsside stop

3 - The comment about the Camry V6 was not from me. Some Toyota engines are prone to sludging when incorrect lubricants are used. Mostly Toyota engines are very easy on their specified lubricants

Regards
Doug