Wes Duenkel
February 7, 2018

High performance engine building is the art of attention to detail. Top engine builders don’t take anything for granted.

John Bouchard, engine builder at Boost Addicts in Madison, Tennessee showed us that even the simple procedure of measuring piston ring gap is detailed. “If you don’t measure your ring gap consistently, you can get into trouble. Too much gap, and you’ll have blow by and waste power. Too little gap, and under boost the ring ends will hit each other and break.”

Bouchard showed us first-hand how the measurements can differ, and how to get consistent results. “The rings need to sit square in the cylinder bore, otherwise you’re just guessing. I use a piston ring squaring tool to set the rings at a consistent depth.”

We witnessed a five-thousandths difference after using the piston ring squaring tool. That’s the difference between fast and failure!

1. Bouchard placed a ring into the cylinder by hand to first demonstrate how inexperienced engine builders check ring gap. It measured 0.024-inch in this position.

2. Using a piston ring squaring tool sets the piston rings at a consistent depth because the user can pull the ring up to the surface of to tool to ensure that the piston ring is square to the cylinder bore.

3. After using the piston ring squaring tool, the ring gap measured 0.019-inch. That’s a 0.005-inch difference, which in the world of high performance engine building, might as well be a mile.

4. Bouchard uses a ring filer to set the gaps to his specifications. He adds, “File your rings in a different part of the room so ring filings don’t rain down on your clean engine.”