Q: I have a well-maintained 1998 Toyota 4Runner Limited with 239,000 miles. The truck has been awesome, no more than normal maintenance issues. The problem is one of the lifters is knocking. I hear it ...

Riding on last month's How It Works topic (cams) is this month's topic—lifters. These cylindrically shaped components contact the lobes of the cam to convert the eccentric shape of the lobe into ...

The engines of yesteryear were pretty simple, with tappets clackity-clacking away on cam lobes, opening valves, and making a ruckus while doing it. Mechanical lifters were adequate for valve operation ...