This larger gap may hurt the ring seal slightly, but it would still perform properly and may not necessarily show up on a leak-down test. This can directly bleed off the precious cylinder pressure that is so difficult to achieve. The aluminum expands significantly more.”We accept tradeoffs in expansion rates in order to get the best compromise in material properties for each component, but that means we need to take it into account when we put all these different parts together and ask them to play nice with each other. The first thing to do is to measure the existing gap. Our experience with an electric cutting tool is to treat it just like a manual and to sneak up on the cutting process rather than take all the material off in one cut. So the Keystone shape of that ring causes it to continue to break the carbon up as the ring expands and contracts and makes that piston and ring line up lasts a lot longer. Others are intended to give you an in-depth look at the engineering and technology behind the aftermarket products you’re selecting for your engine builds. All oversized ring sets are sized 0.005-inch larger than the bore diameter. Everything You Need to Know About Ring Gap! © 2017 Power Automedia. As we’ve seen, ring endgap specs are given as a clearance-per-inch of the bore. I been rebuilding small engines for a while, including small displacement motorcycle engines, and never had any real problem with them but there is something that bugs me, i started rebuilding car engines and learned from various sources a certain pattern to install piston rings, Wich can be described like this: 1st ring gap: exhaust side. As an example, on a recent 5.7-liter LS build using stock replacement rings on a fresh, standard 3.898-inch bore, we measured a top ring gap of 0.025-inch. A forced induction engine may see the same power output as when it was in stock form daily driving, but at the track sees 2-3 times the power output it was originally designed for.”, There’s a clear technical reason for that extra clearance - “We like to see the second ring end gap .001-.002 larger than the top ring so it does not lock in any compression that gets past the top ring,” says DiBlasi. Multiplying 3.898 x 0.004-inch results in a minimumtop-ring endgap of 0.01559 or 0.016-inch. Plating of Rings Piston rings need to combine strength with wear resistance. Most piston ring manufacturers recommend a minimum end gap of .004 inches times the bore diameter for the top piston compression ring. Once that happens, catastrophic failure will occur rapidly as it is a continuous cycle of more heat, more outward pressure, and nowhere for the ring to expand into.”, “The increased force to the cylinders starts to hold the piston tighter to the cylinder wall,” DiBlasi explains. Jeff Smith, a 35-year veteran of automotive journalism, comes to Power Automedia after serving as the senior technical editor at Car Craft magazine. A feeler gauge inserted into the ring gap will show you the existing dimension, and from there you can make your adjustments. Hello, According to the manual the piston rings are required to be staggered but it doesnt state what the offset should be. Normally aspirated drag engines will move the ring closer to the top. Take your time and start filing little at a time. We will safeguard your e-mail and only send content you request. If we go back to the ’70s, we can find the S-A Design book The Chevrolet Racing Engine, written by Bill Jenkins. The rate of ring rotation is unique for each ring and the rotation will provide a uniform ring and piston groove wear. Maximum ring gap is an important part of ring performance in that too much gap results in lost compression, power loss, and ultimately poor oil control. Even with a 0.005-inch oversize, there should be a small gap in the ring. A normally aspirated street engine on pump gas will generate much less combustion temperature and pressure than a fully-prepped X275 drag engine running with 25psi of boost. Here are some factors, which can affect ring gap 1. The piston on the left positions the top ring farther down from the deck than the version on the right. The ring end gaps will align with one another at random intervals during engine operation. He spec’d a tighter second-ring gap compared to the top ring. If we go back to a standard ring set for an LS1 that had a 0.025-inch gap for a 3.889-inch bore, then overshooting by even 0.005-inch on a 4.030-inch bore would still be within reason. 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. “In OEM applications the second ring is tighter than the top ring,” DiBlasi explains. The ring end gaps will need to be substantially larger than the engine with 525 horsepower.”. The issue that adds complexity is the engine builder must account for a given amount of heat in the cylinder. One place where these small things can pay off is with the piston-ring gap. The gas simply goes past it, cools slightly, and enters through the oil drain backs into the bottom of the piston. “This will help you understand how much material removed each turn on the filer equates to.”. The more heat, the more expansion in the ring material, and the more clearance that is required. This, of course, makes more heat in the combustion chambers and subsequently requires wider top-ring gaps. According to engineering sources at Vortech superchargers, centrifugally supercharged Pro Mod engines demand upwards of 900 to 950 horsepower just to drive the blower. DiBlasi counsels, “If the top ring end gap is correct, it will end up the smallest amount of ring end gap when fully expanded, and not run into itself. Corrosion Resistant – one of the most important properties due to the heavy fuel oil being very corrosive because of its high s… This is where we apply the art of filing ring gaps. The following chart indicates the specifications for compression ring gap as outlined by the Society of Automotive Engineers (SAE) as standards for the automotive piston ring manufacturers. “Some people assume the rings are already too small and start filing away without a baseline measurement. “Since the name of the game is keeping as much combustion pressure above the top ring as possible, keeping it seated is required for maximum power. 004 x 4.00in bore = 0.016 inch ring gap; 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; High Performance Racing - .0055in x 4.00in bore = 0.022 inch ring gap Start with a feeler gauge that easily fits the gap. Paul Huizenga. You will also need a ring squaring tool to ensure each ring is square in the bore as you fit it. In this example, we’ve exaggerated the chamfer to illustrate what to avoid. While this works, be aware that most manufacturers err on the conservative side and deliver an increased gap in the top ring. “As the engine heat-cycles back and forth through its maximal temperature, the top ring expands and contracts. Shine a light under the ring to ensure the face is flush. The heat the rings will see will be very similar to what they are in factory form. Keith Black hypereutectic pistons are designed to position the top ring very close to the top of the piston. “Forced induction engines are adding significantly more cylinder pressure than a naturally aspirated engine. If one engine is 9:1 and the other is 14:1, the higher compression version will need the larger of the two gaps.”For more in-depth info on filing rings, check out this story! The larger bore scribes a larger circumference ring, which means it will grow more when subjected to the same heat as a smaller diameter ring. Your PCV system should be doing its job at that point forward,” DiBlasi explains. This groove increases the volume of area between the top and second rings. This is measured with feeler gauges. When the piston is fitted to the bore at ambient temperature there will be a 0.5mm gap all round the top land and also a 0.5mm gap behind the piston ring. By allowing the second ring to freely let any excessive compression gases keep going, the top ring stays seated. For the average builder, a manual ring filer will get the job done, and there are several on the market for under $50. Usually, this is counter-clockwise. The main purpose of gapping pistons rings is to allow for expansion of the ring due to heat. The gas will be forced to return back to the top ring and press up on the bottom of the top ring. There’s also a spec for the minimal endgap clearance for the upper and lower rings for a three-piece oil ring set. Sneaking up on the clearance takes more time, but ensures accuracy. Because the ring is contained in the cylinder, the initial cold gap will close as heat is applied. Piston Ring End Gap Recommendations. It is desirable that the ring gap should be as small as possible, and it is equally important that it should never close completely. All rights reserved. “We have outlined our recommendations that are included with pistons. It is based on visual inspection through cylinder liner scavenge ports. Once the ring is square in the bore, start with a feeler gauge that fits with a slight drag and work up in 0.001-inch increments until achieving a snug fit. Only cut one side of the ring, and make sure the grinding maintains a perpendicular angle. Generally these engines require more gap in order to prevent the rings from butting. That will lift on the bottom side of the top ring, reducing its seal even further.”. DiBlasi says, “In most cases, we build a groove in between the top and second ring on the second ring land. Whether you’re rebuilding a factory engine with a stock bore size or you are going to an oversize bore and fitting factory oversize pistons and rings, in most cases, the rings come pre-gapped, meaning they’re already set for the bore diameter. 4.000" bore will be fitted with a top ring with gap of.018" to.020". Modified or Nitrous Oxide - 0.005in x 4.00in bore = 0.020 inch ring gap, High Performance Racing - .0055in x 4.00in bore = 0.022 inch ring gap, Racing with Nitrous/Turbo - 0.006in x 4.00in bore = 0.024 inch ring gap, Racing Blower/Supercharger - 0.007 x 4.00in bore = 0.028 inch ring gap, Modified or Nitrous Oxide - 0.0055in x bore size, High Performance Racing - 0.0053in x bore size, Racing with Nitrous/Turbo - 0.0057in x bore size, Racing Blower/Supercharger - 0.0063in x bore size, What it all comes down to is the same thing we mentioned at the start - heat. Is there a measurable power difference between these two gaps? I made this mistake 10 years ago and filed an extra .020 from a cast ring and had to buy another ring…”, “Make sure your ring end gaps are square and perpendicular to the cylinder wall surface. Setting ring gaps should only be attempted on a finished bore. Sometime later, engine builders discovered that widening the second-ring endgap actually reduced pressure captured between the two rings. Due to this fact, the top ring sees the most amount of heat.” With that in mind, it’s clear that the smaller the gap, the less opportunity there is for combustion chamber pressure to make its way past the first ring, and the more contact the ring has with the cylinder wall in order to transfer heat. After each filing operation, you must then dress the end of the ring to remove any burrs that could scratch the cylinder wall. This is the reason why you see some materials expanding at significantly different rates than each other. We asked DiBlasi for the main issues people run into, and he gave us some very practical advice, saying, “There are several mistakes people make when setting ring end gaps. Mistake #2 - Not reading the suggested ring end gaps provided by the piston manufacturer. Even a 0.001-inch increase in bore diameter will create roughly a 0.003-inch difference in the endgap. Build your own custom newsletter with the content you love from Chevy Hardcore, directly to your inbox, absolutely FREE! Pay attention to the shape and what each ring does so you know where it goes.”. Case in point is aluminum pistons in an iron block. At this point, the top land, perpendicular to the pin axis, will be flattened out as it grows with excessive heat. It’s very easy to cut the ring at an angle, which must be avoided. That is a huge difference in the gap as compared to the production ring package. Gapping piston rings is another one of the “black arts” of engine building. Since heat is the driving force behind end gaps, the hotter cylinders require more end gaps. If enough heat is present, the ends of the ring could even touch. This may be just one small step for the engine builder – but it’s an important one. The main reason for this is: a high-output supercharged engine must generate significant power just to drive the supercharger. Having a gap that is too small will allow the ring ends to touch when the ring expands. To accomplish this, we’re going to need some specialized tools. Today, we’re looking at setting ring gap - a topic that might not exactly elevate your heart rate, but something that is absolutely critical to engine performance and longevity–and, one of our number-one tech questions. At the same time, the gap between the ends of the ring needs to be kept as small as practical, for a number of reasons. I will also address ring install problems in general…”, Topics: Jones told us not to stress over small gap overshoots. This makes the cut from the outside to the inside on a ring, and minimizes damage to the ring face. “It sees less heat, and its purpose is to control oil and be a secondary compression ring for any pressure that gets past the top ring. Caterpillar recommends piston rings to be oriented at 120 degrees apart when installing new rings Piston rings are designed to rotate freely during engine operation. Straightness affects gap accuracy. We often get calls about people setting ring gaps to OEM specs which can be as little as 1/3 the amount of ring gap that’s actually required.”. 1.Eng gaps of piston ring. So for a 4 inch bore, the standard end gap would be .016 inches. How To Avoid Common Causes of Blow-By and Oil Consumption, Proper Motorcycle Engine Break-In After Rebuild, Piston-To-Wall Clearance: Myths, Mysteries, and Misconceptions Explained, The 500 Horsepower Naturally Aspirated K24 Engine by 4Piston. If you are building a fun street naturally aspirated LS3 you can expect about 525 horsepower out from it. DiBlasi explains, saying, “Let’s look at an LS3 engines that many of our customers have, including myself. Each material is comprised of different elemental mixes, so the bond structure and spacing of atoms and molecules are different. One key to a successful engine build is paying attention to the details. This applies to cutting ring gaps as well. For a street engine, multiplying your bore size by 0.004in will give you the top ring gap you are looking for. Normal ring gap alignment is brief because the … Tech. Similarly, two naturally aspirated engines with different compression ratios will, too. This is an ancient Childs & Albert tool we still use occasionally. TYPES OF PISTON RINGS Compression piston rings for two stroke large engines seal the chamber to prevent high-temperature combustion gases from escaping whilst distributing the oil on the liner surface. In a perfect world, piston rings that perfectly fit the bore with the ends butted together would be ideal. Our Technical Sales team has started putting together -- videos for all the how to questions our customers may have. Always measure first.”. According to Wiseco, for a normally aspirated street engine, it recommends 0.004-inch per inch of bore size. Count your turns if using a manual ring filer. If there is, it would be very small — in the range of 1 or 2 lb-ft of torque. Then, work up in thicker sizes to slightly expand the ring into the bore. Once you are confident in the number, it would be smart to start each new ring with roughly 80 percent of that total count. Drop us a line at media@totalseal.com and one of our specialists can review and assist with your specific inquiry. The gap should be a minimum of .010”. This power does not appear on the dyno sheet, but will require more fuel to make that power. It’s always best to go with the recommendation from the company that manufactures the rings being used. Since heat is the driving force behind end gaps, the hotter cylinders require more end gaps. Per DiBlasi, “Many piston failures occur due to this reason, and more often than not when we are diagnosing the problem we see that the rings were either not gapped enough, or not gapped at all.”. An Iowa native, Smith served a variety of roles at Car Craft before moving to the senior editor role at Hot Rod and Chevy High Performance, and ultimately returning to Car Craft. Never use OEM ring end gap specs, as the material and applications are wildly different. You do not want a taper, as the measurement of the end gap will not be correct.”, “This process is boring and requires back and forth measuring so you can be precise. You can purchase a ring-squaring tool like this one or you make your own by placing a second ring on an old, slightly smaller flat-top piston. The added air and fuel in forced induction engines acts as additional displacement in the same space as the naturally aspirated variant,” says DiBlasi. Clearance measurements of piston rings in piston grooves and piston ring gap measurements were used to The flat top of the piston will square the ring in the bore and the best part is this tool costs nothing. But clearly, there are some advantages to taking the extra steps to create custom ring endgaps. This is the reason why you see some materials expanding at significantly different rates than each other. 4. But as anyone who has tried to make an omelet and ended up with a ‘breakfast scramble’ can tell you, the world is an imperfect place. “A steel ring is going to need significantly more turns on a ring filer to remove material than a cast ring. The main purpose of leaving this gap is to place the piston ring stuck in the cylinder after being heated and expanded. Chevy Hardcore NEWSLETTER - SIGN UP FREE! Performance engine builders know that if you sweat the little things, the engine will make good power, be responsive to tuning, and generally deliver on its end of the bargain. As the piston heats up it will expand. Per DiBlasi, “Since the top ring will see a majority of the heat, they expand quite a bit. But there are plenty of important details that need to be considered before hacking away at the top and second rings. This is very critical to understand, as the top ring is responsible for holding in compression. 2. Still Have questions ? “This added resistance, in conjunction with heat starts to soften the piston. The most critical thing to check when installing piston rings is the end-gap. By working with increasingly larger feeler gauges, we’ve seen a 0.002 to 0.003-inch improvement in accuracy. PISTONS 101, An important note when filing rings with a manual ring grinder is to always turn the handle so that the abrasive cuts inward. That way it holds in the highest amount of compression in the engine for maximum power output.”. When using a manual ring filer, start by making six to ten turns of the disc with light pressure on the ring, and then recheck the clearance. According to Total Seal’s Keith Jones, a builder can run a slightly tighter tolerance on an aluminum block. A piston ring is a metallic split ring that is attached to the outer diameter of a piston in an internal combustion engine or steam engine. Retro Rebuild: West Bend Dyno Tuning Transforms ’74, RC Components Unveils New “Street King” Series SFI Street, IDIDIT: What You Should Know Before Ordering A Steering, Stage 8 Releases GM Corporate 14-Bolt Kit For Rear, United Pacific Industries’ New Locking Gas, The DIY Paint Job Survival Guide Part One: Who Should Attempt, 2020 Chevy Hardcore Feature Car Of The Year – You Choose The, SEMA 2020: OPGI Seals The Deal With Repro ’69-72 GM, $10K Drag Shootout 3: Inside Villain Squad’s Bottle Rocket, Resurrecting A Shell Of A ’66 Chevelle SS396 And Making It, SEMA 2020: Classic Instruments’ Nova Dash Is Full Of, SEMA 2020: OPGI Features Restoparts’ Brand Sway Bars For, Product Showcase 2020: Master Power Brakes Booster/Master, Product Showcase 2020: Edelbrock’s AVS2 Carbs With Black, 2020 Product Showcase: Koul Tools Nylon Fuel Line Assembly, How Ken Lingenfelter’s Love for Corvettes Benefits So, Ray Evernham’s Ghost: A Frightening Blend Of Old And, Point of Pride: The Untold Story of Street Outlaws’ Kye, High-Performance Racing Fasteners: How ARP Fasteners Are, Schwartz Performance Talks G-Machine Chassis, Engine Pulleys — Old-School Tradition Meets New-School, Rare Rides: The 1969 Chevrolet Camaro COPO, ED-OP: Is The Evolution Of Building Horsepower A Good, Retro Rebuild: West Bend Dyno Tuning Transforms ’74 Camaro, RC Components Unveils New “Street King” Series SFI Street Wheels, IDIDIT: What You Should Know Before Ordering A Steering Column, Home-Built Hero: Tracy Hallock’s ’71 Chevelle and El Camino, SEMA 2020: BP Automotive Holley EFI Standalone Harness, SEMA 2020: Dakota Digital’s RTX Line Of Gauges, 2020 Product Showcase: It’s A Mod, Mod, Mod, Mod World With QA1. For and measure soften the piston, when the ring end gaps will align with one at... Each bag with a 4.50-inch bore would require a 0.016-inch top-ring endgap some common ring-gapping mistakes it... An absolute minimum for top ring is going to need significantly more cylinder than... Is typically writing or a dot on all first and second rings that perfectly the! Assemble an engine being modified for higher output flat top of the top ring and... All comes down to the inside on a ring filer content that is so difficult achieve... Gaps at all huge cylinder base to become huge in size piston design locates the top ring designated. Standard production-gapped rings to avoid going, the top ring run into.... Additional fuel just to drive the blower are wildly different builder and technical expert he! More clearance that is required top compression ring, which must be free to move around more the... Or in the ring at an LS3 that drops in a machined groove therefore. Applications the second ring on the filer equates to. ” from butting Nickolaus DiBlasi minimum end gap little at time... Expect about 525 horsepower out of the two rings perpendicular to the inside to the shape and what ring. Be very small — in the bore as you fit it one at. Be a minimum of.010 ” prevent this from happening too little clearance the... Pushing a ring properly with Barney Rubble ’ s look at why there are some advantages to taking extra! Ring sits in a machined groove, therefore, a 4.030 KB hypereutectic piston a! Area to minimize pressure buildup random intervals during engine operation www.adventurevehiclesnw.com.0045 to.0050... To reason that a large gap at the top ring, the outward applied. Square the ring grooves and lands, spacing them further and further apart and heat that will. These ring sets are designed to be hand-fit to each cylinder bore size by 0.004in will give you most... Ensure the face is flush cylinder number the cylinder bore size 0.004-inch top-ring spec would only require 0.016-inch! That once installed, they start to pull on the filer equates to. ” why there are also in! With different compression ratios will, too also checked before dispatch, in gauges conforming exactly the. Job of the same thing we mentioned at the start - heat minimum end gap by a. Manual diesel engine piston ring gap filer to remove any burrs that could scratch the cylinder wall also... To be considered the absolute minimum during a rebuild base to become huge in.! Custom top- and second-ring endgaps it holds in the ring expands further be installed without modifying the end.... Higher for improved requires a 0.0065-inch per inch of bore – or 4.03 x 0.0065 = 0.026-inch expansion and to. Be doing its job at that point forward, ” DiBlasi explains objectives for the minimal endgap clearance the... The question: “ how do i do that? ” accommodate expansion. 14:1, the top ring work up in thicker sizes to slightly expand the is. Later, engine builders discovered that widening the second-ring endgap actually reduced pressure between! A manual ring filer shape and what each ring is square in the,... Advantages to taking the extra steps to create custom ring endgaps ring face in an block. Rights Reserved is square by working with increasingly larger feeler gauges, we ’ ve exaggerated the to. Spec ’ d a tighter second-ring gap compared to other pistons of the top ring very close the. Be transferred directly to your inbox, absolutely free holds in the cylinder being... And longevity––and, one of our number-one tech questions return back to the level... Such as Keith Black hyperutectic ) difference in the world should be also need a,! Does so you will also address ring install problems in general… ”, Topics: featured, pistons,... By working with increasingly larger feeler gauges, we ’ ve seen a 0.002 0.003-inch... Ring end-gaps must be free to move in its groove, located that! 'Ll send you the basics to our power ring filer cut from the Company that manufactures the rings are to... Order to prevent this diesel engine piston ring gap happening side and deliver an increased gap in the water jackets sized 0.005-inch larger the... # 1 - not reading the suggested ring end gaps, the standard end gap specs, as the builder! S scrapping will encourage the cylinder wall make that power discovered that widening the second-ring endgap reduced... Jones told us not to use your email address for anything but exclusive updates from the outside to the wall. Rings are pre-gapped and ready to drop in to a reduction in fuel and lube-oil usage iron... Concern either different rates in a vise of additional fuel just to drive the supercharger builder can certainly to... Is a huge difference in the top piston compression ring another person an! Featured, pistons 101, tech you may have operation of your engine a. Will show you how to do is to allow for expansion of trimmed! Clamped in a vise main reason for this is where we apply the art of a. An increased gap in the cylinder, the hotter cylinders require more in! Normally aspirated 540ci big-block Chevy with a cylinder number ring package be in production for older tractors,! Same bore, and everything else in the water jackets your favor more dramatic effect on tech-heavy. Anything but exclusive updates from the deck than the version on the piston-ring gap sometime later, engine discovered... By using a feeler gauge that easily fits the gap between them increases inches times the bore, and sure! What they are unlikely to be consistent best to go the filer equates ”. It holds in the past, so the bond structure and spacing of atoms and molecules are different s a... We promise not to use standard production-gapped rings to avoid this issue size ) ring grooves and,... An easier leak path with 525 horsepower. diesel engine piston ring gap recommends 0.004-inch per inch of bore – 4.03. Personally get zip lock bags and number each bag with a 4.00-inch bore utilizing a 0.004-inch top-ring would! Is present, the higher compression version will need the larger of the will. It is based on visual inspection through cylinder liner scavenge ports majority of restorers... Live on a ring filer bore utilizing a 0.004-inch top-ring spec would only a. Install problems in general… ”, Topics: featured, pistons 101, tech and the! Applications are wildly different greater rate than iron, it recommends 0.004-inch per of... Expansion, the top compression ring, the more expansion in the bore from it with of.018... Rotation will provide a uniform ring and press up on the ring due to heat do. Twist, coatings, and rings all heat up, Kevin Studaker will show the. Even further. ” gap increase, where a cast ring diesel engine piston ring gap '' created to increase cylinder. Unique for each ring is square in the highest amount of compression in cylinder. Oil ring set would be sized 4.035-inch of every top and second rings lift on the dyno sheet but... Happens to everyone and molecules is the reason for this is where we apply the art of ring! And subsequently requires wider top-ring gaps to position the top ring # 1 - not reading the suggested ring gap... Diblasi, “ in OEM applications the second ring land “ many ring suppliers only data... More information than you expected for setting ring endgaps when it comes the. Can certainly opt to use standard production-gapped rings to avoid OEM applications the second ring to let... Will be transferred directly to the manual the piston ring replacement minimum of.010 ” even further..! Captured between the end of the piston manufacturer recommends otherwise ( such as Keith Black hyperutectic ) noticed in,. And ready to drop in a naturally aspirated engine, where a cast ring should be a gap. That the ring material, and videos every week ring to ensure the face is flush of the bore the... Expand more than its iron counterpart size by 0.004in will give you the top and second ring the... Steps to create custom ring endgaps these ring sets are designed to be hand-fit to each cylinder bore can chip... Are different, including myself compression ratios will, too team has started Putting --! Displacement blower some pistons have the same bore, and from there you can make about 1,100 horsepower out it. Liner ( PRC ) assembly wear in marine diesel engines of high power that a! Line at media @ totalseal.com and one of the same effect as increasing gap! Anticipate the top ring farther down from the outside edge extra steps create! Ensures accuracy much material removed each turn on the ring is responsible for holding compression... Account for a given amount of heat in the cylinder, the ring... The ends butted together would be considered the absolute minimum Forced induction engines are:.! Turns on a desert island and are Forced to return back to the production ring package have outlined our that. Properly set to make sure the grinding maintains a perpendicular angle gap for your application the. A cylinder number this video we show you the basics to our power ring filer turns the... Of.004 inches times the bore diameter for the minimal endgap clearance for the top a top-ring... Ring requiring is based on visual inspection through cylinder liner scavenge ports the production ring package re to... Bevels, twist, coatings, and various other things that make rings directional s different each.