VIDEO: Piston Ring Basics with MAHLE Motorsports

When it comes to rebuilding an engine, some enthusiasts simply choose to farm out the work to a much more experienced individual. Whether its because they lack the knowledge or simply the confidence to tackle the task at hand, many find themselves overwhelmed when it comes to understanding how an engine works. Thanks to the invention of YouTube, it’s becoming increasingly easier to grasp the information needed to undertake such an operation.

Our friends at MAHLE Motorsports understand this, and that’s why they’re among the leading companies in the industry working diligently with us to help car guys earn the knowledge they need to potentially become their own engine builder. But it starts with the basics, first.

Just over a week ago, MAHLE posted this video highlighting pistons and pistons rings; what they do, how they work and how to understand the job that each of them do. Providing insight along the way, is MAHLE’s very own Bill McKnight, who’s a Training Team Leader for the company.

Starting off with a piston for a Chevy Cruze, Bill points out the grooves for all three rings on the piston. Citing that most modern engines rely on a 3-ring piston; the top ring, the second ring and the oil ring, he goes on to explain what each ring’s intended purposes are.


Bill explains, “The top ring, it’s job is 90% controlling compression. It keeps the gases up in the cylinder and out of the crankcase. “The second ring,” Bill continues, “surprises most people – because most folks call it a compression ring – it’s primary job is to scrape oil off the cylinder walls. We call it ‘fine oil control’ in the ring business.”

Turning his attention to the bottom ring, or oil ring, Bill tells us, “Now the lower ring is referred to as an oil ring, and because of that, it’s easy to figure out that its job is to control oil also. It’s what we refer to as ‘gross oil control,’ it scrapes most of the oil down off the cylinder wall and the second ring meters the last little bit of the oil off, leaving just enough oil to lubricate the ring pack – it’s that simple.” We couldn’t have said it better ourselves, Bill. There’s actually a follow-up video to this one, and we’ll share that with you next week. See you then!


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