Helping Your Clunker Clear The Air

Coming motor-vehicle inspection crackdowns in many urban areas threaten to all but junk the remaining gas beasts of yesteryear. No more slipping through inspection with a wink and a grin. Pending Clean Air Act regulations will force owners to pass rigorous new emission procedures that could flunk as many as a third of cars tested. New York, New Jersey, Ohio, Wisconsin, and Texas are among states adopting tougher testing.

Older cars have the disadvantage of 10, 20, even 30 years of wear--and on engine components that by today's standards are primitive. But weep not, junker lovers. These old bombs--and there are millions still on U.S. roads--can be upgraded to meet even California's supertough laws. "What you're doing is adapting '90s technology to the power engines of the '60s and '70s," says Stephen Arnoldi, a mechanic in Paramus, N.J. Beyond improved performance, you get 10% to 20% better gas mileage, helping to pay for the upgrades, which are largely bolt-on jobs that require little labor.

Poor emissions result from faulty carburetion--the inefficient delivery of gas and air to the engine--and bad ignition--the failure of the spark plugs to fully burn the gas-air mixture. Improving carburetion is a logical first step. A new high-performance Holley carburetor goes for $300. Carter and Rochester also offer new units. And for as little as $600, you can install electronic fuel injection.

Another approach is to upgrade the ignition system. For around $12, you can install an MSD Ignition system from Autotronic Controls, which vastly boosts voltage sent to the spark plugs for more thorough burning. It also sends a multiple spark at lower revolutions per minute, where emissions are at their worst.

LIGHT BEAMS. Or you can switch to an ignition system that sends spark to the plugs electronically, eliminating the use of points. Worn points can cut engine efficiency--and being mechanical, they're less reliable as engine rpms increase. Mallory's $125 Unilite emits a light beam that triggers the spark; the signal stays steady as rpms climb.

An innovation, due out this spring for around $150, is a computer, attachable to pre-emission-controlled carburetors, that automatically adjusts fuel-mixture richness for different driving conditions and maximum efficiency. Lean Power of Silver Spring, Md., says its unit reduces carbon monoxide by as much as 80% and hydrocarbons by 30%.

Before making changes, have your mechanic check the entire engine. Simple problems, such as cracked spark-plug wires, can scuttle even the fanciest upgrades.

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