Technical The Great Engine Oil Debate

[fiat500]

I’m confused. Why does it say oil grade 15w-50 under additional info but on tech info is says 10w-40?

I think they just copy and paste stuff. But it might point to both versions having the same additives. It's the additives information which is so hard to find with most oils. Halfords do both of these at a mid-range price.

Few of us have access to, nor have the time or need to be bothered with analysis of our engine oil. So every observation about the stuff tends to be anecdotal. I think that personal experience is invaluable but when you see so many different suggestions maybe a bit of science is useful?

I've found that my engine runs cool, "quietly", starts well hot and cold, is not bad against leakage and the oil retains its pale appearance for a long time when I use Mobil 1 10W60 but it's seems very expensive and is possibly a bit too viscous as the weather turns colder and my journeys are shorter and less frantic. It also achieves the "SN" rating which seems to indicate that it will be low in those essential "vitamins" that the camshaft needs.

 

[gordinir8]

I am currently using castrol 10w50 mineral, do you think that switching to castrol edge 10w60 will be a step up for a stock 650?

 

[Toshi 975]

In a recent conversation with a clever engineer he told me he was going for the 10/60 fully synth option for his newly rebuilt 594 engine. He had once been part of a team who carried out a laboratory test on the oil. An engine (type Unknown) was stripped and everything carefully measured. After reassembly the engine was run in the lab for the equivalent of 100,000 miles under heavy load. Then dismantled and measured again. The components showed no signs of wear so the conclusion was that that oil definitely protects the engine and stops wear. Sounds impressive and also explains an earlier point I raised when I was told that fully synth is not suitable for bedding in new piston rings as that would rely on a tiny degree of wear to get the best seal.

 

[the hobbler]

There is another good reason for using modern oils---power gain. Whilst I realise that 8% of 17.5 isn't very much, it all helps. I use the figure 8% because that was the gain used by putting a modern 10/60 oil, under test conditions, into a Ferrari 250GTO engine. The test, on a dynanometer, was carried out 3 times to ensure accuracy. A 'base' figure was obtained using the normal oil, the oils was drained out of the engine, and then re-filled with the modern 10/60 'Nanno-drive' oil; the gain in power was 8%. As I have mentioned before, ask any classic-race-engine development engineer what is the simplest way to gain power, and the answer will be---modern lubricants.

 

[fiat500]

In a recent conversation with a clever engineer he told me he was going for the 10/60 fully synth option for his newly rebuilt 594 engine.

That will be another good oil although I'm pulling back slightly from my previous arguments in favour of such a high viscosity as 60 grade.
I found this comparison table for the Castrol as compared with the motorcycle brew from Mobil; this is a quotation from another forum.

Mobil 1 specify considerably higher ZDDP levels for flat tappet applications. Here are the values for comparison:

"Castrol Edge Sport 10W-60 ZDDP 0.10% Phosphorus 0.09%
Castrol Edge 10W-60 ZDDP 0.11% Phosphorus 0.10%
Mobil 1 15W-50 (designed for flat tappets) ZDDP 0.13% Phosphorus 0.12%
Mobil 1 V-Twin 20W-50 (4T oil) ZDDP 0.17% Phosphorus 0.16% *

* Motorcycle (4T) oils are not subjected to the compulsory reduction of ZDDP and Ph."


https://socforum.com/forum/forum/stag-owners-club/soc-forum/16985-zinc-classic-oil-claims/page2

 

[Vitesse]

That will be another good oil although I'm pulling back slightly from my previous arguments in favour of such a high viscosity as 60 grade.
I found this comparison table for the Castrol as compared with the motorcycle brew from Mobil; this is a quotation from another forum.

Mobil 1 specify considerably higher ZDDP levels for flat tappet applications. Here are the values for comparison:

"Castrol Edge Sport 10W-60 ZDDP 0.10% Phosphorus 0.09%
Castrol Edge 10W-60 ZDDP 0.11% Phosphorus 0.10%
Mobil 1 15W-50 (designed for flat tappets) ZDDP 0.13% Phosphorus 0.12%
Mobil 1 V-Twin 20W-50 (4T oil) ZDDP 0.17% Phosphorus 0.16% *

* Motorcycle (4T) oils are not subjected to the compulsory reduction of ZDDP and Ph."


https://socforum.com/forum/forum/stag-owners-club/soc-forum/16985-zinc-classic-oil-claims/page2

Your just confusing me now! So are currently opting for Mobil 1 V-Twin 20W-50 because 20W will be thicker in winter, 50 because it will remain thicker at higher temp and ZDDP higher because it will lessen the wear on flat tappets?

 

[fiat500]

Your just confusing me now! So are currently opting for Mobil 1 V-Twin 20W-50 because 20W will be thicker in winter, 50 because it will remain thicker at higher temp and ZDDP higher because it will lessen the wear on flat tappets?

Mobil V-Twin is apparently not available in the UK so that's just incidental info from someone else.

The No. 1 thing seems to be that these older engines need high levels of ZDDP. It seems that legislation prevents the manufacturers from putting more than 1000ppm of the stuff into engine oil intended for road use in passenger cars. So they put in amounts much less than 1000 and use different additives which make the oil more slippery. Even some of the "Classic" oils have ZDDP at these low levels and some claim that there is no longer a need for so much ZDDP since part of their purpose was to soak up lead compounds from petrol residues.

Motorcycle oil, being exempt from the legislation governing cars, is allowed to have high levels of ZDDP. It also tends not to have slippery additives because these mess up the clutch. As many motorcycle engines are air-cooled and tend to run hot in the same way as a Fiat 500 or 126, the viscosity ranges tend to be similar to those originally recommended by Fiat in moderate climates such as Scotland.

The first of the two numbers in the multigrade oil rating is its notional viscosity at (lets call it) colder temperatures such as when first starting. So the lower this figure, the more easily the engine will turn and the more quickly oil-flow will get where it is needed. The second figure is the effective viscosity of the oil at very high temperature and the higher that number, the thicker it will be.

So the "art" in this is to get a "Goldilocks" range which will neither be too thick nor too thin at both ends of the range. Fiat suggest 15W40 for my engine; many people use 20W50; technically too thick at startup and too thick at speed. 10W60 is technically too thin at startup and far too thick at speed because the viscosity increases are not in simple steps....60 is apparently pretty thick!

I haven't even started on the debate about synthetics...but as these are more stable at high temperature I have a leaning towards using them.

So I'm looking at Mobil 1 15W40/50 because it's synthetic, has a lot of ZDDP in comparison with most oils, is thinnish in winter and thickish in summer.

Phew!!!

 

[Vitesse]

Oh dear!!! I assume that it’s a bit of a slow day with horrible weather up there? Well it is down here

As you are one of the few people who drives a 500 in the winter regularly then all of what you have posted is pretty relevant. But you’re inching back nearer to 20W-50 all the time. A simple solution could to be to use classic 20W-50 and add a ZDDP additive to it when you change the oil?

https://www.frost.co.uk/zddplus-ant...MI_azCj-SI3gIVZrvtCh35SglnEAQYAiABEgK6ZvD_BwE

But then again!!!!!!!

https://www.thoughtco.com/debunking-the-motor-oil-additive-urban-legend-726162

 

[fiat500]

If you have the time........ obviously many people, including this writer, have thought about the matter before.... additional worries if you have a performance camshaft.

https://www.economist.com/babbage/2010/11/05/the-difference-engine-all-change-oil-change

 

[fiat500]

20% off Mobil oils at Halfords just now....they seem to no longer stock the 10W60 but...

https://www.halfords.com/motoring/motorcycling/motorcycle-oils/mobil-1-racing-4t-15w-50-4l

 

[Bleeding Knuckles]

Greetings, For what it's worth I always use Mobil 1 10w 60 it has a racing application for older engines and an oil seal preparation to help with the leaks!!! A long time ago I ran a Smart 4-2 with a Brabus tuned 800cc Suprex engine, the car lived outside in all weather down to minus 20deg C on one night. The engine never gave any problems when starting, always gave good oil pressure and I thrashed it wherever I went. Passing the posh boys in their range rovers at 90mph on the motorway was great fun!! I don't care about the cost it's the quality I worry about
Ian.

 

[fiat500]

I just did my first engine-oil change with my latest favourite lubricant; Mobil 1 Racing 4T:

https://www.halfords.com/motoring/motorcycling/motorcycle-oils/mobil-1-racing-4t-15w-50-4l

This engine-oil stuff that I'm always going on about when I'm not going on about clocking up miles or engine-timing advance is very subjective without testing and analytical facilities. But I have noticed a positive difference since using it; absolutely minimal leakage, lower oil consumption (obviously related to the previous) and a nice-sounding engine.

Having just dug up a PDF from Mobil which gives more detail on the specs. for the "sister" oil in the series, I also have even more satisfaction that on the technical side, particularly with relevance to the massive ZDDP content, this oil seems tailor-made for a hard-pushed, flat-tappet, air-cooled Fiat.

https://mobiloil.com/~/media/amer/us/pvl/files/pdfs/mobil-1-racing-product-guide.pdf

 

[The Whitakers]

A great read gents and not uncommon to ones I have read on VW forums especially the part about 'ZDDP' additives...…..


It has been mentioned about using minerals on new engines to run them in to ensure that the rings wear slightly etc and form a great seat, this is what I have always been instructed to do by the 'old boys' that build engines and indeed what I do when I rebuild any engine...….


For me in my standard air cooled engines it's 20/50 all day long, I even used it in my LT40 2.4td motorhome for a few years as they tend to run hot.


I've known people rebuild engines and use 'Millers classic' and for some bizarre reason they go pop after a a couple of hundred miles, however I know people that use it all day long with no reported negatives....maybe just coincidental?!…….


When I get my 1776 FI VW lump running I'll run it in on 20/50 but will be changing to a fully synthetic afterwards, this thread has got me thinking again so I'm going to go do some more research!


As for the door handle angle...…….surely its a push!?! (runs for cover)