Oils

[BenzBoy]

Just some interesting reading:
http://www.penriteoil.com/uk/nextpage.php?navlink=Zinc in Engine Oils
http://www.focfloridaregion.com/edu/oil.htm
http://www.carbibles.com/engineoil_bible.html
http://www.abc.net.au/science/k2/trek/4wd/june99_1.htm
And the more I read the more I wonder...there is no substitute for regular changes but I would like to know more about the science of oils.
Regards,
BenzBoy

 

[B13]

Looks like Penrite are making a push in the UK. Good on them... but many of their products are waaay to thick to sell in any volume there hence their UK web site makes no reference to HPR-40 and -50.

Following their Aus web site recommendation I'm running HPR-30 in my 6.9 and can happily report that I have not heard that noisy lifter once since putting that oil in.

Going against their recommendation I run HPR-15 in the RX4, and since its got zinc in it I may consider it next time around when I change the 6.9's oil, because when they are both up to the same working temperature the oil pressure is exactly the same.

My wife's Mits Verada runs HPR-10 because thats what they recommend and I prefer to leave that car alone and not worry about it.

Curiously you might be thinking I'm doing an oil flush on my TeamW116 450SE today which will consist of about 6 litres of the cheapest crappiest K-mart oil ($9.98 for 4L) and some Nulon engine oil flush, I'll then be replacing that after 20min running time with Pennzoil High-Milage 25W-60 and see how my oil pressure and tailpipe bluey oil smoke goes.

I.

 

[BenzBoy]

And this morning I was talking to a Mobil rep who assures me that the oil they provide to service centres is not the same as you buy off the shelf: that it is better qulaity. I checked with MB and they say the same. I checked with an Independent and he says the same.
There appears to be an issue here. Does Mobil really produce one quality for service centres and another for the rest of us?
Regards,
BenzBoy

 

[OzBenzHead]

[...] the oil they provide to service centres is not the same as you buy off the shelf: that it is better qulaity. [...]
BenzBoy

BenzBoy: Is that the retail, off-the-shelf, bought-by-us oil that is the better quality - or is the service-centre stuff better? Just needing clarification, thanks.

BTW: I've been feeding my Benzes Penrite oils for years.

 

[BenzBoy]

Sorry OBH - the claim is that what is supplied to service centres is better than what is supplied to the likes of K-mart, Repco etc and the price is higher in the case of service centres...even at mates' rates. Why????
Regards,
BenzBoy

 

[OzBenzHead]

Thanks for that clarification, BenzBoy.

Can't say I find it surprising; a similar situation used to exist with house paints (may still be so for all I know - but I'm long since out of touch with the industry).

 

[B13]

I'd have thought the inferior product would have been given to the service centres. To me, a fleet car serviced regularly by the book would be more tolerant to lower quality oil if it were serviced at 10,000km on the dot rather than a home mechanic who may let the service interval drag out to 15,000 or 20,000km... or is it the other way around?

(My 6.9 came to me with Valvoline Durablend oil in it. A quick google revealed its an oil supplied only to service centres in bulk. I can't say it was bad, but I was never happy with the oil pressure reading at idle (about 1.0) when hot and the occasional ticking valve lifter. The oil was looking black at about 5000km so it was changed at 8000km to Penrite HPR-30, which has given me a 1.5 oel pressure at warm idle and no ticking lifters. I've only done about 2000km on it but the oil still looks nice and clean. Its my guess that Durablend is probably better for smaller displacement multi-valve engines. Although the 6.9 manual states 15w40 is acceptable, I'm not comfortable with anything less than 20w50 in such an old engine. clearly the original owner agreed as the service docs which came with the car show it was run on 20w50 for the whole 120,000km the 1st owner covered in it... )

We (my mate and I) buy Penrite Oil in 20l drums from the manufacturer in Melbourne, but they also have large 44 gallon drums of the stuff for service stations... I find it hard to believe there would be any difference in the HPR-15 whether it was bought in 5L or 44 gallon...

I.

 

[OzBenzHead]

I might have to discuss this with my service man. He uses - with my approval - Penrite HPR oils in all my cars (though I can't recall the numbers that follow "HPR").

Anyone here know of an accessible (and affordable) means of having some samples tested?

 

[Michel]

Certainly the saying applies:

Oils ain't Oils...

 

[BenzBoy]

Well just don't go for a higher viscosity oil to effect what seems to be a cure for low oil pressure. Pressure and flow are two different issues. Use a higher viscosity to achieve higher pressure readings and you may well starve a bearing etc. So, when someone says to you that their car uses no oil between changes, ask what viscosity they use and if it is higher that 5-50 you know there is an issue. The more I fond out about oil the more I realise it is a trap for the amateur armed only with a little knowledge...and I inclde myself in that category.
Regards,
BenzBoy

 

[s class]

Although the 6.9 manual states 15w40 is acceptable, I'm not comfortable with anything less than 20w50 in such an old engine.

Could you please explain this a bit. I've never really got my head around viscosity ratings. If we take 20w50 as the 'default', how does 10w60 compare? Is it better, worse, more suitable, less suitable, thinner, thicker or what?

Thanks

 

[BenzBoy]

As I understand it - the default is a 30VI rating at normal operating temperatures - at start up 30VI is too thick so viscosity additives are included to thin the oil so it will circulate more quickly 5VI or 10VI in a modern engine and 20VI in an older one- at higher temperatures greater thickness is required to compensate for wider engine tolerances just to maintain flow and adherence to cylinder walls etc so the VI is raised to 40 or 50. A worn engine will burn oil at 30VI as it will enter the combustion chamber more easily but at 60VI oil consumption will become negligible.
In an older engine a 0-30 oil will burn away so quickly that there is a risk of oil starvation but in a modern engine which has been computer milled ther tolerances are so small that it works just fine. Add to that the drive to meet petrol consumption regulations and companies like GM are recommending only 0-30 oils.
The ideal for an older engine which has some wear might be 0-70 but really that is only disguising the wear, if you use oil consumption as a way to measure wear.
Well, that's how I understand it - and all knowledge is tentative.
Now, a limited number of companies produce the same oil stock that is used by smaller companies so what advantage do the smaller companies have? None that I can see unless they use more expensive additives - which they have to buy from the larger manufacturers anyway.
As to some of the issues with high viscosity oils let's take a quote from the Nulon homepage -
The use of high viscosity engine oils will contribute to lifter noise as it reduces the flow of oil through the lifter and takes longer to pump up initially. Reduced flow means more opportunity for particles to settle in the lifter. High viscosity oils generally oxidise more readily and produce more carbon. This is because the thicker oil takes longer to drain away from the top of the cylinder head (the hottest lubricated part of the engine). Generally speaking, high viscosity engine oils take longer to drain to the sump for cooling and longer to circulate; hence they do not carry away heat as quickly. This contributes to accelerated oxidation and carbon and sludge formation.
For more info go to http://www.nulon.com.au/products.php?productName=Lifter-Free_and_Tune-Up and then click on 'detailed information.'
Regards,
BenzBoy
Regards,
BenxBoy

 

[s class]

Thanks Benzboy, that makes some sense of some issues I'd never considered before.

I'm specifically unsure what to use in my 6.9's and in my W140.

My W140 is just such a modern engine with (well, originally it had) tight tolerances. It has a tendency to have hydraulic lifter tick. Now the big 'but' is the engine is somewhat worn.

I've been using 10W60 synthetic for the last 50 000km - maybe something thinner might improve the hydraulic lifter's cause?

The alternative I'm considering is Catrol Magnatec, which is 10W40 - I'm just a bit scared of oil consumption.

 

[BenzBoy]

Benz recommends Mobil 1 Synthetic 5-50 now for the 450. Interestingly, the original recommendation for my Spirit was 20-50 back in 1993 but there has been a recent service bulletin revising that to 5-50 fully synthetic.
Regards,
BenzBoy

 

[Styria]

Hi everyone, I guess one could talk about this forever and a day after, and still not finish up with any specific sort of conclusion. I personally have used various oils from time to time. I started off initially (Mercedes ownership) with Mobil 1 and continued using it for a considerable period of time.

Then the cost factor got to me, and I started using one of the more expensive variations of Shell, but together with an additive, namely PRO-MA.

I then switched to Castrol Magnatec (still with the additive) and I found that to be a better oil than the Shell - less smoke on the over-run on the open road. I then had a brief flirt (well, 8k. kms) with Nulon full synthetic which was perfectly okay but, again, expensive and I am now again using Castrol Magnatec - again, with no problems. However, it also has started creeping up in price. Personally, I tend to think that if one pays extra, you get better quality and I have no choice but to stick to that - within reason.

BenzBoy, it seems almost implausible that a Company rep. would basically denigrate his own product and, in my opinion, his suggestion that the retail product was inferior to what Service Centres are supplied with, that's exactly what he is doing. Hard to believe, and I am sure his Company would not be impressed. Who really does know ? Insiders ? the people that are packing the stuff ? I certainly have no idea.

B13 - I have seen your story referred to elsewhere - may even have been on TOPKLASSE as well, but am not sure. I have also seen a frontal photograph of your engine sump area, and it certainly seems to indicate that the engine in your race car has not been particularly well looked after. I hope your oil changes and flushing the engine will work, but I have my doubts. You may well find that it is tired - just general wear and tear. Please take no offence - to me, anyway, you may well have a major job on your hands.

Michel -"oils ain't oils" - is there more to know about this debate ? Interested in your valued opinion. Regards Styria

 

[B13]

B13 - I have seen your story referred to elsewhere - may even have been on TOPKLASSE as well, but am not sure. I have also seen a frontal photograph of your engine sump area, and it certainly seems to indicate that the engine in your race car has not been particularly well looked after. I hope your oil changes and flushing the engine will work, but I have my doubts. You may well find that it is tired - just general wear and tear. Please take no offence - to me, anyway, you may well have a major job on your hands.

At the price I've paid for it I bet it is tired old engine... when I bought it it only ran on 4 cylinders. Through intensive reading, testing, learning trial and error, help from TK and the other place, it now runs... well.. about as well as I could expect a V8 engine in an $800 mercedes to run... I've addressed each problem in a methodical manner and spent money where I've needed to. True to good design now that it does run right at least makes decent power, no knocking, tappets and chain are noisy (new chain/guides/sprockets time), and now that its had an oil flush treatment and Pennzoil high-milage oil put in, the smoking has gone away and the oil looks golden-brown as opposed to black. I congratulate myself on how far I've gotten with this engine, actually.

Its not going to win any races in its current form - nor is it going to blow up on the starting grid.

Getting back to the topic, so answer s-class question on oil grades, I'm no expert, and I wouldn't make a descision based on info just from me, but my experience is from 20 years of motor sports and owning mostly performance cars... also my sidekick (mechanic mate who helps build the race cars and their engines) works as a hydrualics fitter / engineer so I run most ideas by him...

AS I UNDERSTAND IT: in multigrade oil the 1st number indicates how well it flows when cold and the 2nd number indicates how well it flows when hot. The lower the numbers the thinner the oil.

15W-40 would be thinner than 20W-50 both when its cold and hot
15W-60 would be thinner than 20W-50 when cold and thicker than 20W-50 when hot
40W-70 would be extremely thick when cold and still thicker than 20W-50 or 15W-60 when hot

Thinner means lower oel pressure at idle. I don't like my oel pressure to drop below 1.0bar regardless of how hot or old the engine is so we (my mate BC and I) will try different multigrade oils until we find one which gives us an oil pressure we like at idle. We tend not to deviate too much from accepted norms, and don't run an oil with the first number less than 15, and the 2nd number greater than 60.

On the plus side 15W-40, 20W-50 and 25W-60 are amoung the least expensive oils around and we get good longevity out of our engines due to frequent oil changes - no buggered bearings in 20 years of engines make it clear in my mind the bearings are not starving for oil...

Just my 2c worth, - I'm not wishing to start any arguments.

I.

 

[BenzBoy]

B13 is pretty much on the money there.
Personally I am sticking with the manufacturers' recommendations for Mobil 1 5-50 except where the recommendation is for 0-40.
Stryria wrote - BenzBoy, it seems almost implausible that a Company rep. would basically denigrate his own product and, in my opinion, his suggestion that the retail product was inferior to what Service Centres are supplied with, that's exactly what he is doing. Hard to believe, and I am sure his Company would not be impressed. Who really does know ? Insiders ? the people that are packing the stuff ? I certainly have no idea. No - the manufacturers and Benz are both saying that the product available from a service centre is different from what is available through retail outlets. C'est possible?
Regards,
BenzBoy

 

[Styria]

Hi BenzBoy, well, I must admit that I am staggered - I would never have believed it.

Hi B13 - we don't have arguments on Topklasse - in fact, this thread has led to some very informative discussions. Obviously, in your situation, your methodical attention to eliminating each item as you went along at least has given you the chance, and hope, to improve the oil pressure in your engine.

Now that the oil is clean, it will be interesting to see to what extent your oil pressure reading will improve. It might also be a good idea to change the filter a couple of times.

This takes me back at least twenty years when I rebuilt a Rover 3 litre engine and the oil pressure was less than brilliant. In an effort to trace the problem, we also changed the oil and filter on at least three to four occasions over a period of one week until finally the problem was traced to a faulty pressure relieve valve - from memory. However, that engine lasted beautifully for many years and I put this down to the intial frequent oil changes. Regards Styria

 

[John S]

The oil companies are working their way towards a constant-viscosity oil, so the oil does not thin down or thicken up as the temperature changes, but tries to stay within set limits between the cold and hot ratings listed, eg 15W-50. The more you pay (hopefully) the better the ideal is approached.

 

[BenzBoy]

Update; I have just read a service bulletin from Crewe that states fully synthetic 5/50 should be used in all re-built engines ever made by R-R (and from 1931, Bentley). The bulletin also indicates that if the engine is rebuilt to original tolerances and using modern bearing materials, the projected life of such an engine, assuming correct oil/filter change intervals, should be the equivalent lasting forever......whatever 'forever' means. Scary stuff!!!
I make no comment; just a report.
Regards
BenzBoy