Engine Oil Thread
 

I've been here for an hour searching for a thread where engine oil has been discussed quite thoroughly, does any one know what thread that is ?
There is a member here that worked in the oil industry that posted some very useful info.

Thanks

Thanks Glyn, I did find that one almost right away.
The one I'm looking for was quite long and may be buried in a restoration thread _ probably why I can't find it.
What I can remember is that whom ever it was knew about oil specifically and he worked in the petroleum business, or something to do with it.

The person you are looking for is Glyn.
I am not sure if you can search under the posts that Glyn has put on the forum. Failing that ask Glyn the question again and I am sure he will answer it. A font of all knowledge concerning oil.

I'm a Tribologist. Likely me.

I found it, and no wonder I couldn't find it, the OP labeled it as "Hello There" :icon_rolleyes:

Any body looking for advice on oil, look at Glyn's post's, there is also another link to another forum in there that discusses it further.

Thank you Glyn, I have also found an answer to one of my questions, and that is why is a 10-30 weight mineral oil thicker then a 5-50 synthetic ?
One can't accurately compare motor oils at room temperature, if one compares both at operating temperature, then in the end, the 5-50 will be thicker then the 10-30, even though the 5-50 will be thinner at room temperature.
And this is where people get them selves in a knot, they say " I can't put that 5-50 synthetic oil in my collector vehicle, it's so much thinner then a 10-30, the oil pump won't pick it up properly".
What they forget is that once the 10-30 heats up, it will be thinner then the 5-50.

One has to pay attention the viscosity numbers on the end and realize those numbers are measured when the product is at 100 degrees Celsius.
Yes, the mineral will be thinner at room temperature and at below freezing, that is because the viscosity number on the synthetic as at a 5 as apposed to the 10, but that does not make it a bad choice for an older engine.

The other thing that I find confusing, but not anymore is the use of ZDDP in oils meant for older vehicles with tappets.
I believe it is a just a marketing ploy.
While there is nothing wrong with buying a synthetic oil that contains higher then normal amounts of ZDDP for a collector vehicle with solid lifters and tappets, I don't believe with todays technology of synthetic oils, that it's necessary to look for a product that contains higher then average amounts of ZDDP.

When one thinks about it, todays modern engines with over head cams don't contain roller lifters, the lobes make direct contact right on the bucket lifters, so there is certainly just as much friction there as there always has been, just like in older engines with solid lifters that ride off cams below the valve train with rocker arms.

ZDDP was removed or reduced in modern oils to protect catalytic converters, from all the reading I have been doing, ZDDP is an older technology that has been replaced with modern additives and better refinement to produce a better product.

https://www.jaguarforums.com/forum/m...6/#post2014912

Pleased you found what you wanted.

Yes ~ one needs to understand Viscosity Index (VI). i.e. rate of change in viscosity for a given change in temperature. Synthetics are high VI ~ i.e. they thin less with rise in temperature & thicken less than mineral oils with a reduction in temperature.

Wanted to recommend this great guide by Roadologist
I found it very clear and concise as I was researching the topic in preparation for a DIY oil change.

P.S. DIY is awesome :icon_headbang:

That is a very good basic guide. I could nitpick the language used slightly but won't. It has been written for the layman.

I wish a few mechanics would read it. They talk more nonsense about oil than most & perpetuate old wives tales.

Unfortunately many vehicle owners globally go to their mechanic for lubrication guidance. Something mechanics are not trained in & frequently give very poor advice. :):icon_beerchug:

Re Jaguar.

http://www.jagstyperegister.com/foru...e+oil&start=20

Some aspects of engine design have changed over the years. Thanks to better manufacturing, clearances have been reduced, allowing (and requiring) lower viscosity oils. Some manufacturers, not Jaguar, have found it cheaper to use higher grade materials, rather than drill holes to ensure delivery of sufficient oil. Hydraulic valve lifters are also a convenient way of hiding relatively rapid cam wear. Finally, changes in materials and surface treatment have also been made to compensate for the absence of ZDDP. As a consequence, a 'classic' oil may be as good an option for a classic engine as a more sophisticated modern synthetic.

Perhaps the most important thing with oil is to change it regularly. Don't break the 10,000 mile/12 months rule.

Oops, lost a paragraph from my post. It said that I'd support everything that Glyn has written. The last couple of years, I've not done my own oil changes and my mechanic has used a good quality 10w40. When I was doing it myself I used a Castrol synthetic 10w60 in the MK2 and DD6.

I would be happier with the SAE 10W-40. Jaguar never prescribed greater than an SAE 40 & only in tropical conditions.

The trouble with so called Classic Oils is they use poor quality Base oils and cheap VI Improvers & shear out of grade.

Modern synthetics will substantially increase engine life. This is not a subject of debate.

Hi Glyn,
I live in Queensland and have a 1964 Daimler V8.with BW 35 transmission. The car has the original engine which is very tired blows smoke on start up and leaks from the rear main seal. I am not in a position to reco the engine at the moment but it drives ok and is mostly used on club runs about 100KM.
My question is what engine oil would you recommend I use ?
I would be very interested in your expert opinion.
Regards,
David Bruce.

In Queensland's temperature profile I would run the car on a mineral Monograde SAE 40. Even if it is a diesel oil like DELO as long as it's petrol performance is SF or greater. You know you are delaying the inevitable & with short runs that would be fine. Change the oil every 5000Kms or 2 years. I've lived in Aus. I know the ambient conditions.

My recommendations on these threads are for engines in top condition & rebuilt using modern equipment, methods & materials.

My Mk2 service manual (no date marked, but I’d guess it’s about 1969 as it is post-BL and mentions Castrol GTX) indicates various oils from 10w30 to 20w50 without mention of environment. The handbook that came with my Mk2 (early 1963) lists SAE 30 or 20w30 for summer, 20 or 20/20 for winter and SAE 40 for tropical.

The maintenance handbook for the DD6 (late 1986/early 1987) lists 5w20 to 5w40 for extreme cold (less than -10˚C), 10w30 to 10w40 for cool (-20 to +15 ˚C) and 10w50 to 20w50 for more normal conditions (-10 to above +40 ˚C).

I don’t know how deeply Jaguar ever went into engine oil testing. I’d suspect that they followed general practice and would only change their recommendation if something went wrong. They always advised to use well known and regarded brands.

When I was using Castrol 10w60, the cars were spending a lot of time in hot climates (Italy and Texas). I think Jaguar recommended it for V12s in those days. Of course, there wasn’t so much choice 20-30 years ago; it may well have been the only grade of synthetic that Castrol sold. I favoured Castrol over others (say Mobil 1, which might have been a 10w40 at the time?) mainly because I’d seen good reports of their products in the 1970s and 1980s when I worked in the products side of a large oil company.

Large oil companies spend a lot of effort on engine lubricants. I presume that also goes for most of the specialist lubricant companies, but I don’t know. The majors also had a lot of freedom in selecting which crudes and which refineries and processes were used for their base oils. That may be less the case today as refining capacity has been sold off. Certainly, they tried to use the best base oil and additives for every application, and I don’t think that would have changed. They spend a lot of effort on R&D and testing. Much of that is aimed at the more popular engines. However, since those engines are generally designed more on a cost to manufacture basis, what is good for them should work for a Jaguar. I’d never use cheap oil from a less respected brand.

One thing that we haven’t discussed is how the car is driven. It can be easier to produce oil for racing than for everyday use. (Those who formulate those oils don’t admit it). At least, they know how the driver is going to treat the engine and that it will be maintained. A private car might spend its life in long high-speed journeys on the autobahn or autostrada or on daily 10-minute commutes. Or, in the case of many of our old cars, they may well sit for several weeks without going out of a nice warm garage. The people who formulate and those who recommend lubricants have to find a compromise bewtween all those demands!

Hi Glyn,
Thanks for your prompt reply.
David B.

Hi Peter3442,
My tired old Daimler is our second car and used around town when needed and on club runs at weekends or coffee mornings mid week. Usually less than 100KM. At the moment engine oil of a good quality is cheaper than an engine rebuild.
Regards
,
David Bruce.

You will be absolutely fine on an SAE 40. We have a fair bit of evidence on the Register with these so called "Classic Oils" & that they are not using the more expensive shear stable VI Improvers. They shear hopelessly out of grade becoming thinner at operating temperature with use resulting in a noticeable drop in oil pressure between oil changes. And we are talking recently rebuilt engines.

If I may hijack the thread slightly, a friend has a 2017 XF with the 3.0 supercharged engine. The manual calls for a special JLR oil from Castrol as the only oil to be used in that engine.Apparently it has a special dye in it, so a dealership can tell if the proper oil is used. A bit about the oil: https://www.jaguar.ca/en/about-jaguar/castrol.html

Is there any particular thing that makes this oil so special that an SN oil of the recommended viscosity could not be used instead? I ask after he took it to the dealer and got a bill for $800 for an oil change.

All the major oil companies have an equivalent product.

Example of a few:

https://www.opieoils.co.uk/c-3569-ja...ngine-oil.aspx