Video: How To Adjust Valves With Jeff Smith’s Garage

You know him, you love him, and now you get to see him. Jeff Smith, who has long been renowned for his technical writing (among other skills in the editorial world) is stepping in front of the camera with his new YouTube channel, Jeff Smith’s Garage.

In his videos — like the one posted above — Smith walks you through some of the trickier processes involved in engine performance, explaining what’s happening along the way, with tips and tricks he’s picked up over his 40-plus year career sprinkled in. In this video, he brings us tips on how to adjust valves, whether you’re setting lash or preload.

“If you talk to ten different mechanics, you’ll get ten different ways to set lash on your engine,” says Smith. “It’s not that any of those are wrong, just that they all require certain specific knowledge and reference materials right in front of you. If you were on a desert island and needed to set lash on a small-block Chevy, I can show you a technique that’s simple and easy to remember.”

Before getting into the easy-to-remember technique, Smith differentiates between preload and lash, explaining that preload is what exists on a hydraulic lifter setup, where the whole assembly is compressed a certain depth into the lifter, while lash is the mechanical clearance between the rocker arm and valve tip used in a mechanical lifter setup.

Those four little letters are the key to setting lash on any Otto-cycle engine. When the exhaust valve is opening, the intake valve is closed. Conversely, spin the engine over until the intake valve opens and then starts to close, and the exhaust valve is sure to be closed at that point.

Smith explains that since you always want to adjust a valve that is fully closed with the lifter on the base circle of the camshaft, an easy way to remember that is “EOIC” or exhaust open, intake closed. This method doesn’t rely on any knowledge of a particular engine’s firing order. Instead, relying simply on remembering how an Otto-cycle engine works (suck, squish, bang, blow).

“When you crank the engine over in the normal direction and you see the exhaust valve begin to open, you know the intake valve is closed and can set the intake valve side,” Smith says. “If you keep rotating, you’ll see overlap and see the intake valve open. If you keep rotating through to where the intake valve starts to close, you know the exhaust valve is closed, and you can set it. It really is that simple.”

With the theory explained and demonstrated, Smith goes on to show how to properly adjust the valves, whether they are using hydraulic or mechanical lifters. “Once you have that first pair done, you only have seven more pairs to go,” says Smith. “I like to just go in order down the line of the engine bank. Yeah, you’ll spin the engine over a few more times, but you aren’t trying to chase firing order and running the chance of getting lost.”

About the author

Greg Acosta

Greg has spent fifteen years and counting in automotive publishing, with most of his work having a very technical focus. Always interested in how things work, he enjoys sharing his passion for automotive technology with the reader.
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