Engine oil

[chriswgawne]

I received the attached datasheet in the post recently which I found interesting. I hope its legible.

I haven't  related the data to our cars/engines yet but since the early 1980's (when I bought my first Porsche 911) I have used Mobil 1 10W40 in all our cars whether old/new design and whether worn or newly rebuilt or B20 race engine.
I did > 500,000 miles in my first 911 with an engine rebuild at 280,000 miles and the piston rings were still within spec amazingly (but I replaced them along with the timing chain) and understandably the engine used some oil after the rebuild whereas before it used < 1l /000 miles which I think was the advised new vehicle Porsche consumption. My 2nd 911 which was a turbo bodied 993 Carrera 4 did 240,000 miles before it was stolen and used no oil and my current 993 twin turbo only uses oil if driven fast, presumably through the Turbo. All of this on Mobil 1.

In the UK we have an early BMW Supercharged Mini Cooper S which has done 240k miles with no engine problems apart from a recent new timing chain tensioner and chain and this car uses some oil but with no sign of oil smoke on the overrun so I presume its just piston and piston ring wear. I used a non franchised independent BMW workshop to do the timing chain work and they suggested using a 10W60 engine oil to reduce oil consumption which was about 1l per 1,000 miles. I tried it but it didn't really seem to make any difference and I see that Porsche have brought out their own very expensive oils for so-called Classic models which are basically all the air cooled 911s. These are available as 5W50, 20W50, 10W60 and 10W50.

And then the synthetic question? Back in the 1980s when I first started re-building the occasional Fulvia and Aurelia type engines, somebody whose opinion I respected suggested that using synthetic 10w40 oil in a rebuilt 'old' engine would inevitably lead to oil leaks. I took no notice and am pleased to say that I have had no problem with oil leaks due to the particular oil used.

I have to also say that the prospect of having different engine oils for all our different cars (all with petrol engines ranging from our 330k mile Landcruiser to a new 310 bhp VW Golf R) has the potential to give me a headache. Much simpler to use the same fully synthetic good quality oil in all of them.

What do others do I wonder?

[KeithWade]

Interesting subject is engine oil Chris though obviously no real right or wrongs I guess....

I looked at the history of oil changes for my 1973 series 2 Fulvia and discovered the below. It has done nearly 235,000 miles with no obvious wear to the bores! We replaced the piston rings in 2012.....

The car has had 62 engine oil changes in its life.
Engine oil has been topped up 58 times in its life.

Between 1973 and 1974 oils used were: Shell and Millers 20/50.

Between 1974 and 1976: Castrol 10/30 Shell 20/50 and BP 20/50

Between 1976 and 1977: Shell 10/50

Between 1977 and 1979: Shell 20/50

Between 1979 and 1980: BP VF7

Between 1980 and 1982: Duckhams 20/50

Between 1982 and 1992: Duckhams 15/50

Between 1992 and 1999: Castrol GTX 15/50

Between 1999 and 2017 (our ownership): Shell Helix Ultra 15/50

Between 2017 to present: Shell Helix Ultra 10/60.

My father was a motor engineer (unlike myself!) and spoke at length about how much cleaner Shell oils are. I started using the 10/60 after the 15/50 became unavailable. I believe Omicron also advise using 10/60 for Fulvia.