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Politics : The Environmentalist Thread -- Ignore unavailable to you. Want to Upgrade?

To: FJB who wrote (24764)	5/30/2009 5:04:24 PM
From: miraje	Respond to of 36917

Most American cars built from 1975 onwards have catalytic converters to reduce emissions. Lead in gasoline poisons these converters, so unleaded fuel is required in catalyst equipped cars. Engines built since the mid 70's have hardened valve seats to compensate for the lubricating qualities of leaded gas that is no longer used. So, lead does not harm an engine internally, although it does shorten spark plug and muffler life as well as poisoning modern emission systems. Old cars that ran on leaded gas can be retrofitted with hardened valve seats or use lead substitute additives that are available in auto parts stores.