Check the end gap by placing the ring into the cylinder. First, let’s look at why there are differing gap specs.Ī torque plate should be attached to the engine block or cylinder (if applicable), and torqued to specifications. This is created to increase the volume in this area to minimize pressure buildup. Also, note the depression between the top and second ring on the piston to the right.

Normally aspirated drag engines will move the ring closer to the top. Why is there a gap at the top of the piston?

With today’s thin rings, some racers run side axial clearance as tight as 0.0004 – 0.0005-inch, using gas ports to supplement ring pressure. What are the end gap and side clearance of piston ring approximately?ĭepending on the application, the side clearance is typically. Because piston rings need to be expanded to fit over the diameter of the piston itself before they find their home in the ring grooves, they have to be split in some way in order to allow installation. Setting the correct ring gap on aftermarket piston rings is crucial for proper performance and engine longevity. Then, shut the engine off and let it cool until it is warm to the touch. How do you break in a new piston ring 2 stroke?īreak-In – When running your new top end for the first time, keep the engine slightly above idle, with slow and mild revs until the engine starts to get too hot to touch. Mix them up, and it won’t work properly, either. Also, the top ring is often different from the second ring. If the ring is installed upside down, that won’t work properly. Piston rings usually have a chamfer on the back side that uses the gas pressure to help seal the piston ring against the cylinder wall. This area will not have wear from previous piston ring travel, thus giving an accurate ring gap reading.Ĭan piston rings be installed upside down? For high performance engines, the multiplier changes to add more clearance, but the math stays the same: Modified or Nitrous Oxide – 0.005in x 4.00in bore = 0.020 inch ring gap.ĮT piston rings come pre-gapped, however, it is always best practice to check your end gap before installation. How do you calculate the end gap of a piston ring?įor a street engine, multiplying your bore size by 0.004in will give you the top ring gap you are looking for.

You can find out how much the cylinder is worn by measuring ring end gap at the top and bottom of the cylinder. Worn cylinders may have taper wear that increases toward toward the top. Piston ring end gap should be measured with the piston ring positioned near the bottom (unworn) part of the cylinder.

Pre gapped piston rings