How to Check Ring Gap: UTV/ATV Engine

 In Tutorials

What’s going on, everyone? Jake here at Rev Six is bringing you the lowdown on something that might seem small but is massively essential in engine assembly – the ring gap. If you’re tinkering with your UTV or ATV engine and want to avoid common pitfalls, stick with me. Let me introduce a crucial step in your engine assembly process: learning how to check the ring gap.

Check Ring Gap Importance for Engine Health

Ring gap is all about space – specifically, the small space between the ends of a piston ring when installed in the cylinder bore. Why fuss over a gap typically measured in thousandths of an inch? Here’s the deal: piston rings expand when they heat up, and if that gap isn’t just correct, your engine’s performance is going downhill. Too small a gap and the rings might touch each other when they expand, leading to all sorts of mayhem like bent rings, loss of compression, and oil burning.

To keep your engine purring like it should, there’s a simple rule of thumb for your ring gap. You’re aiming for about three-and-a-half to four-thousandths of an inch gap per inch of the cylinder bore diameter. I’ll walk you through how we make that happen, step by step.

Essential Tools for Ring Gap Inspection

Before we start, let’s gear up with the right tools for the job:

  • Feeler gauges for measuring those tiny gaps.
  • A machinist file or a ring filer to precisely adjust those gaps.
  • Flat blade screwdriver and a pick, or in my case, a handy miniature pry bar
  • Sandpaper, calipers (I’ll explain a bit later why these might be optional but recommended)

As I’ll show you soon, our ring filer, snagged for about 30 bucks, is the unsung hero of this process. It ensures that your ring ends are evenly ground and gives you accurate gap measurements. We have some fogging oil and good old contact or brake cleaner to keep everything clean during the process. No messy hands on our watch.

How to Check Ring Gap: Ring Identification and Staggering

Alright, you’ve got your piston rings, and knowing what goes where is crucial. The top ring is generally more rounded and is your main seal, while the second ring is flatter and sharper – think of it as the wiper that follows behind. And let’s not forget the oil baffle ring and the rail rings that ensure your piston stays well-lubricated. These bits are picky and need to be installed just right.

Remember, you want to stagger the gaps to prevent any oil seepage. Each ring should have its gap offset from the others to create an effective seal.

The Nitty-Gritty of Gap Checking

The real magic happens when you check the ring gap. Slide your top ring into the cylinder and square it up – about an inch down the bore is where you’ll measure. But before you break out the feeler gauges, ensure those cylinder bores are clean. I prefer using Deep Creep for a good scrub before installation.

Armed with your calipers, you might measure the cylinder diameter – mine was a 93mm bore, and we typically set the top ring to 15 thousandths and the second ring to 16 thousandths. But – and this is a prominent but – always defer to your piston manufacturer’s specs. They’ve dialed in those numbers for peak performance, whether you’re going stock or building a beast of a race motor.

When it comes to the actual measuring, it’s about finesse – no gloves, careful placement, and one gap at a time. Feeling resistance when sliding in that feeler gauge? Time to file the ring down a bit. Remember, it’s a game of patience and precision.

Grinding for Perfection

“Remember, the top ring gap should be smaller than the second ring to prevent ring flutter and ensure a true seal.”

When your feeler gauge tells you it’s time to grind, do it one ring at a time.

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