FAQ's about Lead Replacement Petrol

A large part of the world use old bike engines
that need lead replacement petrol. (Photo:  Reuters.)

FROM what date will there no longer be lead in petrol in South Africa?

Unleaded petrol was first introduced to South African consumers in 1996. Since then, the use of unleaded petrol has increased gradually and now accounts for about 75% of total petrol sales in South Africa.

In a drive to improve air quality, by supplying fuels that enable the latest vehicle technology, anti-valve seat recession additives (AVSR) will no longer be added to petrol in the production process to produce LRP. The phase-out of LRP has already started, although on a small scale. The petroleum industry is required to produce fuel to international standards, which enable car manufacturers to introduce vehicles with the latest emission and fuel-efficiency technology. This requires the petroleum companies to optimise the current logistics infrastructure to accommodate these requirements. As the demand for “cleaner fuels” grows, the production of lead replacement fuels will cease. When the new clean-fuels II legislation comes into effect in the not-too-distant future (planned for 2017), all LRP production will cease.

Can vintage and classic cars use unleaded petrol?

Vintage cars are typically exposed to such light service that they are not expected to encounter valve-seat recession problems. Thus, using unleaded petrol should not be a problem. However, if there are concerns about the possibility of valve-seat recession, then AVSR bottled additives should be used (to be used in accordance with the instruction on the bottle). Please dispose of empty containers in a responsible manager. The additives are toxic to the environment.

Will my old car suffer from valve-seat recession when using unleaded petrol?

Early model cars built before the mid-eighties often have soft valve seats, which could be damaged when unleaded petrol is used and the vehicle is driven under high speed/load conditions. The occurrence of valve-seat recession is unlikely under normal driving conditions.

How do I know if my car is susceptible to VSR and how do I avoid it?

The Naamsa (www.naamsa.co.za) website will contain a database listing the older vehicles that are susceptible to VSR and which should use an AVSR additive to avoid the possibility of VSR occurring.

Why were AVSR additives added to petrol?

Adding AVSR additives to petrol was considered to be the most economic way of protecting older vehicles that required such a product to lubricate the contact surfaces of the exhaust valves and the valve seats in the cylinder head. Older engines (pre mid-eighties) were made with soft-metal valve seats as they were protected by the AVSR additive in the petrol. If all metal additives are removed from petrol, the soft-metal valve seats may become worn and valve-seat recession may result in loss of compression and power. The most critical conditions for valve-seat recession are high speed and/or high-load driving, which leads to high valve temperatures and hence greater wear rates.

Why is AVSR being removed from petrol?

AVSR additives have been widely used as a petrol additive since the seventies. It is only more recently that there has been recognition of a possible threat of the metallic additives in the environment to human health. Some of the additive technology available in petrol has also been shown to result in the formation of corrosive compounds, which may particularly affect spark plugs and exhaust systems, leading to unnecessary maintenance costs. More importantly, the removal of metals from petrol enables the fitment of catalytic converters, significantly reducing the level of harmful emissions from exhausts.

How will I know which octane grade is the most suitable for my car?

You should refer to your vehicle owner’s manual or check with the vehicle dealer to select the required octane grade. The National Association of Automotive Manufacturers’ website contains the information indicating the minimum octane and fuel-type requirements of the majority of models on SA roads.

Why should I not use an octane grade that is higher than my car actually requires?

Petrol with a higher octane costs more to produce and the higher the octane level, the more crude is required for its production. This has a negative impact on South Africa’s balance of payments. In addition, the production of petrol with a higher octane level requires more severe refinery processing, which results in higher emissions of greenhouse gasses, which harm our environment. The use of octane grades higher than your vehicle actually requires, will cost you more, will cost the country more and could have a negative environmental impact. At the same time, there will be no additional benefit to the drivability of your vehicle by using an octane grade higher than that required.

Is unleaded petrol suitable for motorbikes, lawnmowers and outboard engines?

Unleaded petrol is generally suitable for use in motorbikes, lawnmowers and outboard engines, except for a very few that use old engine technology (these are considered to be minimal in SA). Refer to your equipment dealer if you have any concerns. — WR.