Some of the things said on the subject of engine oil.
Perhaps anyone adding information to the list at the bottom they could use copy and paste, then the previous post could be edited down to a full stop, ready for removing.
Lotus Service notes recommends 3.5 litres including filter change of 10W/30 SF or SG, 15W/40 SF or SG, Mobil One 5W/50 SG
If it were a new car the oil choice would be straight forward, just follow the manufacturer’s recommendation. Unfortunately the Lotus recommendation is 17 years old and oil has moved on a bit.
Here are a few words from an expert at Castrol. The same logic would apply to other manufacturers.
“Changing the oil every 6 months and using the car normally I see no reason why Magnatec 10W-40 SS wouldn't do a good job"
“Doing any track days, then the EDGE 10W-60 FS would offer better performance and protection.”
For the extra cost he would recommend EDGE 10W-60 FS anyway, but do the oil change once a year for low mileage cars, as it will easily do the mileage, he says. It may also be cheaper if EDGE is less than twice the cost of Magnatec.
If he had an M100 he would use EDGE Turbo Diesel 5W-40. He says…
”Ignore the name, it's an excellent high lubricity 5W-40 fully synthetic, suitable for petrol and diesel engines (It’s what I recommend for the Honda NSX ) and has a high lubricity additive package that would offer great protection for your engine - the viscosity is a close spec so less polymer to shear so better VI performance. Other than that, the EDGE 5W-30 could be used, as could the 10W-60, as could the Magnatec 10W-40”
When I enquired with Castrol about Matt’s excessive oil consumption following an oil change on…
http://lotuselancentral.com/forum/viewt ... highlight=
Here’s what they had to say.
(…If the engine was very dirty, and had not had regular oil changes, and the engine has a bit of wear - then it is possible where there could be some carbon deposits built up around the valve guide seals and piston rings where this carbon is actually providing a final seal - if an engine oil with good detergent properties is used, then over time it can clean away the deposits and you could get some extra usage - but you wouldn't see this straight away.
A more likely scenario could be that the oil is oxidised so it is thicker - when you change the oil, the new oil will be thinner and would also show up any wear - especially is it a synthetic which tend to be thinner than the equivalent mineral oils.
If in doubt then a semi synthetic would probably be better bet - detergents in oil don't necessarily "clean" the engine, but stop dirt sticking to it, and hold it in the oil so when it's changed the dirt is flushed away)
From this you could assume for high mileage engines that have always been running on semi synthetic oil it may be best to stick with it.
What the numbers mean…
The numbers show the relationship between modern multi grade oils and the SAE singe grades.
While your lawnmower engine, being small, slow running, and used mainly when it’s warm, will run happily on SAE 30, a car engine needs something thin enough to pump instantly to the camshaft when cold, but thick enough to maintain the pressure when hot.
10W 40 means its starts from cold with the same flowing characteristics as a SAE 10 single grade oil, but rather than thinning as the temperature rises as an SAE 10 would, it thins no more than a SAE 40. Similarly a 5W 50 starts off as a 5 when the ambient temperature is -18°C and doesn’t thin anymore than a SAE 50 by the time the oil is boiling.
You might wonder why you would ever need a 0W, it’s the same as a 5W with an extra bit of something that keeps it pourable under even worse conditions. And while you’re wondering - we used to consider Duckham’s 20W 50 as being a thick oil and now we have fully synthetic 10W 60 being recommended. Fortunately the synthetic oils flow better generally, so the comparison is not exact.
In the middle of the UK 10W-40 would be a good choice. 5W-30 would be more appropriate for Norway and 15W-50 for North Africa. Then there are track days…
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Here’s what other LEC members have said…
ESM: I use Mobil 1 0W40.
Fully synthetic oils are the best by some distance. Friction losses in engines drops by around 4% with a synthetic oil - this gives more power and more economy. They also are the most effective at limiting wear - which is why many engines are best run in with a non-synthetic.
Some older engines (I mean older, I don't mean late 80s) need a more viscous oil because the bearing clearances are larger. Chris Foulds doesn't like synthetics too much largely because of this.
Different oils swell/shrink seals differently. So if you have a borderline seal one oil may be worse than another for loss through that seal. Which oil minimises your loss may vary depending on which seal causes the leak because all seals aren't all of the same composition. Oil formulation is scarily basic when it comes to seal compatibility; they are formulated with a mixture of elements known to cause either seal shrinkage or swell which are balanced to break even(ish). So worse oil loss isn't necessarily a synthetic vs semi or non-synthetic oil issue more a formulation to formulation issue (if Mobil 1 gives you issues another synthetic 0W40 oil might be better).
Synthetic oils can achieve low cold viscosities. So HVLs will pressurise faster with them, although any drips from leaky seals will be worse for the same reason. I'd certainly go 0W for choice. I prefer a W40 because it will give greater engine protection than a W30 (as a result of its higher viscosity) and the last approval Lotus issued was for a 0W40 not a 0W30. That's not to say a W30 won't be ok and it will incur less in the way of viscous losses but I'd say the Elan's engine is from the W40 oil technology era and so I stick with that because clearances etc are likely to have been designed with that level of viscosity in mind.
Engines run with synthetic oils are cleaner, if you put a synthetic oil in an engine previously run on non-synthetic you can dislodge a lot of gunge so run a short first oil/filter change interval if you switch.
Amsoil:
To use any 60 grade oil in these engines is crazy. This is the thickest grade of engine oil there is. Whilst we sell a 60 grade its confined to pre war Harley Davidsons and nitro drag cars whose superchargers force the fuel past the rings (if they have them) and into the oil therby diluting it; so they start thick to end up with something that will let the engine survive.
If you are tracking your car and the temperatures are so high that the use of a 60 grade oil means that its effectively a 30 or 40 at these temperatures then please ask yourselves about the efficiency of the rad or oil coolers (if fitted) Bottom line is get the temperatures down and use the correct grade. The engine oil is meant to be an indespensible part of the engines system rather than being used as a prop. The problem with thick oil is that it causes more friction / pumping losses which in itself creats extra heat , robs power and efficiency and can actually lead to oil starvation when an oil pump cavitates.
Edge is a good product but please stick to what the manufactures originally specified. The improvements in oil which mainly refer to the appearance of full synthetics, have resulted in very much stonger and longerlasting products. Amsoils products are at least 3-5 times the film strength of mineral oils and this strength allows the use of thinner oils to advantage.
Not too sure how a synthetic oil can be thinner than a mineral oil? If it where it would just be graded differently so that it would be the same , if that makes sense.
Specky:
There are Pros and cons to using any oil: - Thicker oil increases pressure and also increases drag on components within the engine. Thinner oil decreases pressure and reduces drag on its internal components, but increases wear. Also the oil pump struggles to get the oil to the top of an engine. So manufactures have made synthetic oils and multigrade oils to get around this. Thus creating idealistic oils that perform well under most circumstances. (Not a recommendation) Most vital bearings in an engine have a couple of thou wear tolerance, so thin oil may be detrimental. IMHO I'd stay with what Lotus recommends, especially when you say that you're in a hot climate and slow city traffic. Those conditions are thinning your oil to start with.
Johnny:
SJ say you should always use fully synthetic 15/50. When I told them my man who did my bearings had put 10/40 part synthetic in, they said to change it soon as, it was doing the engine no good.
Josler:
I’m running Mobil1 0w-40. My friend put me on to this expert on oil and he sent me this info: “The 0w-40 is fine, and not too thin. I would suggest either a 0w-40 or 5w-40 synthetic so you’re on the correct track”
Paul P:
Castrol RS 0/60 FS is recommended by many lotus garages
Rip:
I have a strange interest in oil. The most common Mobil One appears to be 0W-40. There are 4 different Castrol 10W-40 oils: - GTX, Magnatec, Edge & Edge Sport. I am using Edge Sport 10W-60 in mine. I feel that thicker oil like this is more appropriate for a turbo than an NA.
Personal preference would be to use a fully synthetic in the Élan, although this may be a false economy. Changing the oil regularly is the most important thing. Because the turbo bearing gets much hotter than most parts of the engine I prefer to use a thicker oil, hence my choice of 10W-60.
Enright: Says I always use Mobil 0W/40 FS, I recently bought a 20 litre drum from a German seller called "omanitat" on eBay - see here - £105, against £45 for 4 litres from Halfords, and only £7.50 carriage from GERMANY, so basically half price!
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Please copy, paste and amend the list. State SS or FS, N/A or SE