Lead substitute
As lead replacement petrol additive mixtures are referred to a supposed lubricating effect of tetraethyl lead to the exhaust from gasoline engines to replace. They are advertised for use in classic cars .
Tetraethyl lead was added to motor gasoline from the 1920s (in Germany from the 1950s) in order to increase the knock resistance and thus the compression possible in the engine. Because of the high toxicity of tetraethyl lead and its harmful effects on vehicle catalytic converters , it was pushed out of the market from the 1970s and finally banned (e.g. in Germany in 1996). The knock resistance was achieved by other anti- knock agents .
Tetraethyl lead is also supposed to lubricate the thermally highly stressed exhaust valves as well as cylinder heads made of cast iron , since the oxides produced during combustion form a film over them. When switching to unleaded petrol, manufacturers ruled out the need for this lubrication for newer engines; only a few manufacturers did the same for older models. As a result, lead substitutes came onto the market. Despite advertising claims by the manufacturers that lead replacement [forms] a protective layer on the valve disks and valve seats , replaces the lubricating effect of the lead and prevents wear and tear on the valve seats , their necessity and effectiveness remain controversial.
No reliable information is available about the possible functionality of the additives . In a typical product in addition to fuel components, the potassium - analogue of docusate sodium , a surface-active substance contained. Others give "potassium compounds" as the basis of their product.
Individual evidence
- ↑ a b c Additional additives - who still needs lead replacement? - autobild.de. In: autobild.de. March 26, 2003, accessed March 12, 2016 .
- ↑ a b c ADAC Info - Oldtimer & Youngtimer - Vehicle history - Lead in fuel. (No longer available online.) In: adac.de. Archived from the original on March 12, 2016 ; accessed on March 12, 2016 . Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice.
- ↑ Wanted oldtimer: Basic knowledge: Lead additive in gasoline - is this necessary for the engine? (No longer available online.) In: wunscholdtimer.de. Archived from the original on March 12, 2016 ; accessed on March 12, 2016 . Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice.
- ↑ Lead replacement - ERC lead replacement enables all older engines with unhardened valve seats to run on unleaded fuel. In: erc-online.de. ERC - Emissions-Reduction-Concepte GmbH, accessed on March 29, 2016 .
- ↑ 512141_Blei-Ersatz_7_lightbox.jpg (330 × 600). In: sonax.de. Retrieved March 29, 2016 .
- ↑ Lead substitute. In: pingo-world.com. Retrieved March 29, 2016 .
- ↑ EUROLUB additives - car care. In: eurolub.com. Retrieved March 29, 2016 .
- ↑ bluechem lead substitute 1: 1000. In: bluechemgroup.com. Retrieved March 29, 2016 .
- ^ Valve Expert - Motul. In: motul.com. Retrieved March 29, 2016 .
- ↑ Safety data sheet - Castrol TBE. In: msdspds.castrol.com. Castrol , accessed March 12, 2016 .
- ↑ Product information - lead replacement. (pdf) (No longer available online.) In: pim.liqui-moly.de. Liqui Moly , archived from the original on March 13, 2016 ; accessed on March 12, 2016 . Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice.
