Auto Repair Today vs. Yesterday

February 8th, 2016

Many of us (at least those of us past “a certain age”) have fond memories of cars from the 60s and 70s. They were big, they looked great, they went fast, they were Auto Repair in Ozark ALcomfortable, rode smooth and sounded great. The truth is, though, cars from a generation ago required a lot more maintenance and auto repair to keep them on the road than today’s cars.

Before the days of electronic fuel injection, fuel metering was controlled by the carburetor. Carburetors are complicated assemblies, mixing a spray of gasoline with the air being pulled into the engine. They would also incorporate a choke that would restrict air flow for a richer fuel mixture until the engine was warmed up to operating temperature. The carburetor operates on mechanical linkages and the vacuum created from the intake manifold; one of its chief disadvantages is its imprecise fuel metering to each cylinder. The carburetor’s many parts and small internal passages were subject to buildups of varnish-like residue from gasoline, meaning frequent adjustment for fuel mixture and idle speed as part of a routine tune-up. At least a couple of times in the life of the vehicle, the carburetor would have to be removed, torn down and rebuilt, with internal parts soaked in a solvent bath and all the rubberized gaskets and seals replaced.

Prior to the early 70s, breaker point ignition systems sent spark to the cylinders through the distributor and plug wires. The breaker points were a mechanical switch that would open and close hundreds of times per second, allowing current from the ignition coil to make its way through the distributor as a rotor spun inside the distributor cap and delivered spark to the contacts for each individual cylinder.  A vacuum connection to the distributor would vary ignition timing and advance or retard spark according to the load on the engine. These systems were subject to wear due to friction, carbon buildup and oxidization; the points, rotor and distributor cap were generally replaced as part of a tune-up. Often, plug wires were replaced as well, since they could tend to degrade and arc over time. By the mid 70s, transistorized ignitions replaced breaker points; while they required less maintenance and resulted in a hotter spark, they were still a transitional technology.

Older cars also had multiple drive belts for the power steering, alternator, water pump and air pump for emissions control. Multiple belts are long gone, replaced by a single “serpentine belt” which goes to all accessories. The serpentine belt is more space-efficient, since it doesn’t require multiple pulleys offset from each other. It can also be held to a greater tension by a spring-loaded tensioner (for better mechanical efficiency) and creates less parasitic drag on the engine.

With older vehicles, a tune-up was required every 30-35,000 miles or so, for the best fuel economy, power and overall drivability. Today, the carburetor has been replaced by electronic fuel injection, and the distributor, rotor, cap and plug wires have been replaced by a coil-on-plug system that delivers spark to each plug individually. Fuel metering, transmission shift points, ignition, spark advance and emissions are now all governed by the engine’s control computer, and the old 35,000 mile tune-up now needs to be performed at about 80,000 miles or so. Today’s “tune-up” isn’t much more than changing spark plugs, changing the air filter, checking the engine’s vacuum lines and scanning the engine control computer for trouble codes.

The truth is that back in the 60s and 70s, a car with 140,000 miles was usually ready for the salvage yard…or at least required constant auto repair and maintenance to stay on the road. On the other hand, there are many, many post-1995 cars and trucks on the road with well over 200,000 miles on the odometer and plenty of good miles left. Today’s vehicles require a lot less maintenance and are more efficient, powerful and reliable than ever before (with the right maintenance and driving habits, of course).

At RoadMart Inc in Ozark, AL, we’ve been in the business a long time and we’ve seen all the changes in automotive technology come and go. We’ve got experienced, trained auto repair techs, and we hope that we’ll be your go-to resource when it comes to keeping your car on the road for a long time to come. Whether you’ve got a vintage ride or a late-model car, give us a call and make an appointment for auto service today! 

  Posted in: Auto Repair 101