Oil (again!)

[Ozzy]

Just wondering if anyone has used Comma Euro Lite 5-40 fully synth? And maybe could explain why it's cheaper?

 

Noticed this down at my local motor factors, and it's significantly cheaper than the usual Comma. 5 litres for £24, and the 1 litre bottles are £7, which appears to be good value. So what's the catch?

 

When I read the spec on the back of most oils, mostly it seems to read the same, so I'm bemused as to what the actual differences are!

 

Oz.

[gundersen]

Seems to me that whenever oil is being discussed factual arguments tends to leaves the room 😬 But I am watching this space with great anticipation.

[Roger Ford]

EuroLite is a semi synthetic - do you mean Ultralite? It's descibed by Comma as a budget oil and has lower specs than Syner-G - API SL against API SM for example. What difference that makes in real life I don't know. I bought the Syner-G at Halfords at £10 for 4L which seemed like astonishing value to me, though people got a lot more excited about the Comma stuff at £19 for 5L recently.

 

[Ozzy]

Sorry, I did mean Ultralite

 

I missed out on Halfords, as I was away. By the time I got down there, it'd all gone!

 

Maybe an expert will enlighten us shortly?

 

 

 

[Markiebabes]

Nigel I've started using This here supposedly rebranded Fuchs Titan fully synth oil I buy in 20 litre drums at local motor factor for around £67

[StuB]

Hi Ozzy,

 

I don't know if it's on interest but I just ordered Comma 5W50 from ebay at just under 21 quid delivered.

 

here

 

Stu

[Grim Reaper]

the Unipart Pro S 400 stuff is Fuchs Titan 'Supersyn', don't be confusing it with Fuchs Titan 'Race Pro S' which is on a whole level above.

[Ozzy]

 

So come on then. To support that statement, what is the difference between all these oils, which on the face of it, appear to be the same. As per my original question.

 

Oz.

[Jonathan Kay]

Good question. I've come to the conclusion that often nobody knows the answer. The reasons might be:

 

1 There are too many variables (oil type, engine type, use conditions) and the test cycle is too long for anyone to do the experiments needed to find out about wear.

 

2 There's lots of swapping of products, both raw and finished, between products, ranges, brands and suppliers, and only insider knowledge can tell you about that, and the swapping may change over time.

 

3 Many 7 owners change oil much more often than the period manufacturers have to design it for, so success is defined differently for the two.

 

What happens in practice? We make decisions based on tests (where they do exist) that don't meet our uses, plausibility based on formulation rather than testing, and brand loyalty. And price.

 

What is logical behaviour under these conditions? (Captain.)

 

1 Be conservative: our own engines are not the best place to do experiments

 

2 Trust experts.

 

Jonathan

 

Edited by - Jonathan Kay on 19 Aug 2013 16:23:51

[Dr Slotter]

A quick glance at the data sheets for Ultralite 5w40 and Motorsport 5w50 tells me that, other than the viscosity differences, the former has some detergent in it whereas the latter doesn't. That could mean that as the detergent will cause particles to be suspended in the oil, if those particles are bigger than the required oil film in a particular contact you would get increased wear. Generally, high performance engines have smaller clearances, hence thinner oil films, to reduce friction, at the expense of greater wear/reduced life.

 

Edited by - Dr Slotter on 19 Aug 2013 17:13:45

[Roger Ford]

Isn't the thickness of the film dependent on the viscosity, or is there more to it than that?

 

Edited by - Roger Ford on 19 Aug 2013 17:20:32

[Roger Ford]

dupe

 

Edited by - Roger Ford on 19 Aug 2013 17:20:20

[Dr Slotter]

Mostly yes, but the nature of the additive packae can also have an effect. For two oils with essentially the same viscosity/film thickness they can support if one had a detergent that promoted suspension of third bodies (wear particles, for instance) and one didn't, those particles could act as third body abrasive particles, increasing wear. If the particles are large enough (or agglomorate into bigger ones) so that they are bigger than the oil film, the film would break down locally and you would get 'mixed mode' lubrication which is a combination of 'hydro-dynamic' lubrication (i.e. a full oil film) and eventually 'boundary' lubrication (contact asperities meeting). The more of the latter means adhesive wear and two-body abrasion joins the third body abrasion (and makes more third bodies so the wear gets worse etc. etc.). See this image of what's called a Stribeck curve which will hopefully explain further!

 

http://www.ibtinc.com/artman/uploads/1/skf_stribeck_curve.gif

 

As you can see the ideal is on the cusp of mixed to hydrodynamic. In high performance engines where you care less about wear/life you can risk being closer to mixed and the expense of more wear. Performance oils are formulated to promote the formation of this thinner films, other oils are formulated to be more conservative and the expense of more friction. Premium oils tend to have more expensive additives to allow thinner films with less wear, for example.

 

 

Edited by - Dr Slotter on 19 Aug 2013 17:36:50

[charlie_pank]

I reckon I got less for my 20,000 mile K-series engine than I spent on oil to lubricate it. How many of us have kept a 7 engine long enough to notice the different performances of same-spec lubricants?

[Ozzy]

Well.....to be honest, I'm none the wiser! And quite frankly, I'm beginning to wonder, whether any of them make a busting lot of difference, as the fact is, myself, and everyone with a seven that I personally know, changes the oil every 3K or so regardless. So it's hardly in there long enough to deteriorate anyway.

 

I notice that high performance engines are mentioned a couple of times, which I also find quite amusing. The cars may be reasonably high performance, but the engines certainly aren't! The K series (which I have) must be a 25 year old design, originally out of a Rover 200? And even the current Duratech must now be getting long in the tooth, but neither of them were intended for high performance vehicles, were they! It's hardly F1 territory.

 

So, I suppose, the question is, does it really matter, as long as we are using the recommended type/rating?

 

Oz.

[oldbutnotslow]

There used to be a contributor to BC called OILMAN. From memory his posting rights were removed as he was one of the principals of OPIE OIL but I stand to be corrected on this.

Chris is still around on PH

 

Perhaps a phone call to Opie for a chat may well answer your questions. I have found that they are always willing to help.

[Grim Reaper]

I invited Oilman from Opie onto here back in 2004 (don't forget we get a discount on Opie oils website) There are loads of threads about which oil is best and what the differences are between them.Plus a lot of good advice here,here and here

Basically, anything but an 'ester synthetic' oil is not really a 'synthetic' oil, its just a mineral oil that has had so many additives and processes carried out on it that (due to some court decision) it can be 'legally' called a synthetic oil.

I have run my K series for the last 9 years on Silkolene (now Fuchs) Pro S ester synthetic oil (after using Comma for the first year before they changed the Syner-Z to 0W-30 from 0W-40), when I took it apart this year to check and adjust the tappet clearances, the inside of the engine looked exactly like it did when it was put together, clean and shiny everywhere, no black sludge or deposits to be seen.

I for one will not be using any other oil so long as it is available.

 

Edited by - Grim Reaper on 19 Aug 2013 22:47:06