Engine oil

General engine oil guide

Material mix of engine oils

The main characteristics of lubrication of any oil is based on the base oil as well as the physical limits of the oil. The characteristics of oils can be improved with additivates although this can also have a negative impact on some of the oils specification.

Mineral oils

The base of thise oils is the raw oil. In order to get the characteristics of the raw oil to work with modern engines, addities are requires. Theose additives will increase the flow stability, reduce foaming characteristics, cleanliness and more.

Semi synthethic oils

Synthethic oils are made of mineral oils but modified by synthetic processes in order to improve their characteristics.

Fully synthetic oils

These oils are fully snythetical created oils and do not base on mineral oils.

Additives

Additives are any additions to the oil that improve the characteristic of the oil. e.g.:

• Flow stability
• Wear
• Corrosion
• Cleanliness
• Coking
• Sludge protection
• Deterioration
• Oxidation
• Evaporation loss
• Filterability
• Foaming characteristics
• Flashing point

How ever, additives can also have a negative impact on the oil such as decreasing the HTHS.

HTHS - High Temperature High Shear

Since the F20C engine in the Honda S2000 is a very high reving engine, it is recommended to use an oil with a highest possible HTHS. A higher HTHS means a lower fuel efficiency but a better lubrication during higher engine load/stress. Experienced Honda S2000 drivers from various communities recommended to get an oil with atleast HTHS > 4,0 mPas or higher.

Viscosity

Generally speaking there are singlegrade and multigrade oils. We will only use multigrade oils in our Honda S2000.
Multigrade oils will have a viscosity that is thin enough for cold temperatures while still having a viscosity that is thick enough for high temperatures.

The viscosity or flow of multigrade oils is described as e.g. “10W-30”.
The first number “10W” describes the viscosity at cold temperatures (-18°C). The “W” stands for winter.
The second number “30” describes the viscosity at hot temperatures (+99°C).

This means that a 5W-30 oil will be thinner on low temperatures while a 5W-40 oil will be as thin as the 5W-30 on cold temperatures but will be thinner on high temperatures.

ACEA / API Classes

Specifications are important as these indicate the performance of the oil and whether they have met or passed the latest tests or whether the formulation is effectively obsolete or out of date. There are two specifications that you should look for on any oil bottle and these are API (American Petroleum Institute) and ACEA (Association des Constructeurs Europeens d’Automobiles) all good oils should contain both of these and an understanding of what they mean is important.

API

S = Petrol, C = Diesel, although many oils carry both classifications.

• SA - Contains no additives. Not suitable for use in most gasoline-powered automotive engines built after 1930.
• SB - Used for engines with low performance. Contains additives against wear, corrosion and deterioration.
• SC - Used for engines with low performance. Contains additives against coking, sludge, wear, corrosion and deterioration.
• SD - Used for engines with higher performance that were produced between 1968 and 1971.
• SE - Used for engine with high performance and high requirements. Also applicable for “Stop-and-Go”.
• SF - Used for engine with high performance and high requirements. Exceeds the SE requirements in regards to oxidation, wear, sludge protection.
• SG - Used for engines with the highest requirements with special requirements regarding oxidation and sludge protection.
• SH - Coressponds with the SG requirements. Additional higher requirements for HTHS, evaporation loss, filterability, foaming characteristics, flashing point.
• SJ - Succeeder of API-SH. Higher requriements for evaporation loss and there for less oil loss.
• SL - Succeeder of API-SJ with higher requirements regarding deterioration, flow stability, efficiency, cleaning of the engine, wear (especially at higher oil change intervals).
• SM - Succeeder of API-SM with even higher requirements for oxidation stability, cleaning of the engine, wear, deterioration and performance at low temperatures.

ACEA

A = Petrol, B = Diesel and C = Catalyst compatible or low SAPS (Sulphated Ash, Phosphorus and Sulphur).

• A1 - Fuel economy petrol engines with low HTHS (<3,5 mPas)
• A2 - Standard performance level
• A3 - High performance and/or extended drain
• A4 - Reserved for future use in certain direct injection engines
• A5 - Combines A1 fuel economy with A3 performance

• B1 - Fuel economy diesel with low HTHS
• B2 - Standard performance level (now obsolete)
• B3 - High performance and/or extended drain. Exceeds B2 in regards to wear, cleanliness, flow sta-bility and grime level.
• B4 - For direct injection car diesel engines (TDI)
• B5 - Combines B1 fuel economy with B3/B4 performance

• C1 - Petrol and Light duty Diesel engines with disel particulate filter (DPF).Sulfating ash max. 0,5%. With lower HTHS.
• C2 - Petrol and Light duty Diesel engines with disel particulate filter (DPF).Sulfating ash max. 0,8%, HTHS > 2,9 mPas
• C3 - Petrol and Light duty Diesel engines with disel particulate filter (DPF).Sulfating ash max. 0,8%, HTHS > 3,5 mPas

Expiry date of new oil

Oil producers test their oils for stability of atleast 36 months. That means any oil is demonstrably fine to use within an age of 36 months.

Mixing or changing different oils

Generally you can mix fully synthetic oils.
If you want to get completely rid of any oil remainings in the engine (e.g. when switching to a different oil) you can re-fill the new oil three times in a row. The R&D departments of oil producers use the three time re-fill method to make sure that no remaining old oil is left in the gearbox/transmission/engine between their test runs.

Reading the oil level dipstick correctly

One of the common faults when reading the oil level by using the oil dipstick is to remove the dipstick only once from the engine and go with the first reading of the dipstick. This causes two problems:

1. The dipstick will show to different oil levels, depending on which site of the dipsteak you are looking at
2. There is a good chance that remaining excess oil will be on the dipstick

In order to get a correct reading of the oil level dipstick proceed like this:

1. Make sure the engine is warm since the oil will expand under heat
2. Position the car on an even surface
3. Turn off the engine and let it sit for about 10 minutes
4. Remove the dipstick and clean it with a paper towel. Repeat this step 3 times.
5. The 4th time you remove the dipstick, read the oil level from both sites of the dipstick. This will be your definite oil level.

OEM Specifications

• Fully synthethic oil
• 10W-30 for summer usage only (-20°C to +40°C)
• 5W-40 if also driven during the winter (-30°C to +40°C)
• API SJ or better (such as API SL oder API SM)

Recommendations

Generally speaking you want:

• The highest possible flushing point
• The lowest possible pour point
• The lowest possible sulphated ash
• The highest possible HTHS

Throughout the experience of many S2000 communities and drivers the follwing engine oils seem to be recommended and to have gained positive feedback: