Into the 1960’s cars were simple. It was a time when the shade tree mechanic could literally climb inside the engine compartment, make adjustments and replace parts with the skills of a farm boy. However, regular maintenance tasks such as timing, replacement of plugs and points, and valve jobs kept maintainers busy.
By the 1970’s and 1980’s, things like emissions controls, permanently lubricated
drivetrain components and early computers had made cars far more complex to maintain.
But they also laid the groundwork for a third generation of vehicles with such tight manufacturing tolerances, advanced materials and sophisticated onboard control systems, that we would eventually change spark plugs at 50,000 mile intervals. And when was the last time you needed a valve job?