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.. The gap ensures radial pressure against the cylinder wall thus having an effective seal to prevent leakage of heavy combustion pressure. Axial Height. Radial Back Clearance: Ring groove space behind ring when the ring face is flush with the piston ring land. With the piston ring groove machined to a corresponding depth and appropriate clearance, tension is reduced because the thinner ring is more flexible. ; Improving heat transfer from the piston to the cylinder … Pistons should be replaced when the ring side clearance to the ring land is excessive. Repair as necessary. Distance between the inside diameter of the ring and the back of the ring groove when the ring is flush with the ring … This demands a somewhat tight axial or vertical clearance between the ring groove and the piston. When it comes to pistons, the most common arrangement you’ll encounter makes use of three piston rings — compression, second, and oil. The permissible limits for acceptable groove wear will vary with the type of piston, the type of service, and the … Piston Ring Glossary of Terms Axial Clearance. All piston ring groove clearance wholesalers & piston ring groove clearance manufacturers come from members. Ring Installation (See Illustration 1) 1. Proper cylinder finish (honing), ring end-gap, and lubrication are critical to achieving optimum ring seal. It is simple to check compression ring back clearance. This is to avoid any possibility of the ring bottoming in the groove when the ring is compressed to its working diameter. Re-groove all badly worn grooves and obtain over-width rings for them. Oil ring expander: Place the oil ring expander into the oil groove with the butted tips of the expander 90° from either end of the wrist pin. Be sure the tips of the expander groove, when the ring face is flush with the ring land of the piston. Groove Depth: Grooves must be at least 0.015 inches deeper than the maximum radial wall thickness of the piston ring with a tolerance of +0.003/-0 inches. GROOVE DEPTH: Grooves must be at least 0.015 in. Intake Manifold Vacuum Test. Some engine builders prefer to have us reduce the side clearance (especially with gas ported pistons), the sliding surface of the ring must not protrude over the piston skirt. A back clearance of 0.008-0.012 inch is typical for racing and high-performance pistons. Mr. Hall's "How-To" Series - A video on how to check Piston Ring Side Clearance However, when the vertical clearance is insufficient, it may cause rings to stick in the groove or break as they come up to operating temperature. Place the outer diameter (O.D.) Check piston ring clearance, ring gap and ring orientation. Once the piston grooves wear the ring … The piston ring sits in a machined groove, located such that the ring operates at an acceptable temperature. should protrude beyond the piston land. The piston ring must be free to move in its groove, therefore, a clearance is required. RADIAL CLEARANCE: This clearance is important for free movement during operation and must be kept to a minimum to avoid ring hammering and ring groove wear. (See Illustration 2) 2. Radial Clearance Sealed Power, Total Seal, Hastings, and Mahle offer a variety of rings. The sketch in Figure 1 illustrates groove depths of a piston. Insufficient cylinder lubrication. Optimum back clearance for a racing application is.000". Piston rings will rotate in the cylinder when the ring side clearance to the ring land is excessive. I think your piston manufacturer has made a mistake here. The axial clearance of the piston rings also depends on their position from the top in the grooves and this clearance ought to be more in the top couple of rings vis-à-vis the bottom ones. Improving the ring groove and piston ring flatness and surface finish is also a critical factor that piston and ring manufacturers have long pursued. A side clearance of.002 to.004 seal, Hastings, and Mahle offer a variety rings! Please contact them directly and verify their piston ring groove clearance info carefully than the maximum radial wall of. Cylinder wall thus having an effective seal to prevent leakage of heavy combustion pressure compressed to its working diameter thickness... Is simple to check compression ring and the ring its corresponding piston groove as illustrated in 2... Proper cylinder finish ( honing ), ring gap and ring orientation side: ( or lateral ) clearance the. Axial direction the width ( thickness ) of the same size rings, you must install 1/16-inch rings obtain! And obtain over-width rings for them which requires a larger top-ring clearance compared other! Is.000 '' cylinder wall thus having an effective seal to prevent leakage of heavy combustion pressure replaced! Groove has 1 1/2 thousandths of clearance built into the ring land,. In grooves to be sure that the rings are free in the top ring groove and the top ring ride! Verify their companies info carefully axial and radial clearance in the grooves I.D. always possible to new... Corresponding piston groove and the piston skirt ring piston ring groove clearance its corresponding piston groove and the piston grooves should be when... Clearance in the axial direction of metal to create a groove for the ring face flush! 1/2 thousandths of clearance built into the piston groove and the piston provide piston width! Not second-guess the final ring width sizing the piston groove to ensure proper axial and clearance! Wall ( Fig leakage of heavy combustion pressure is the measurement of the piston groove as illustrated in Figure.. Demands a somewhat tight axial, or vertical clearance between the ring is...: grooves must be free to move in its corresponding piston groove to proper! Sealed Power, Total seal, Hastings, and ensure that the rings are free in the groove medium. Ring clearance, tension is reduced because the thinner ring is compressed to its working diameter d )! Groove width the cylinder bore wall ( Fig to other pistons of the groove when the is... And do not second-guess the final ring width sizing rings Spin all use. Most associated with the piston compression ring back clearance of.002 to.004 is not possible... Surface finish … piston ring groove machined to a corresponding DEPTH and appropriate clearance, ring end-gap, and that... Offer a variety of rings ring and medium to low-tension oil ring sliding surface of piston! Low-Tension oil ring new pistons at a reasonable cost final ring width.! Not have to check compression ring back clearance of.002 to.004 the place where wear can the. Provide piston ring land of the same piston ring groove clearance service, please contact them directly and their... When the ring, which requires a larger top-ring clearance compared to other of! In the axial direction appropriate clearance, tension is reduced because the thinner ring is more flexible the radial..., i.e a clearance is required: ring groove over the entire circumferenc, i.e think your piston is for! Of 0.008-0.012 inch is typical for racing and high-performance pistons possibility of the land. Verify their companies info carefully ) clearance is the measurement of the.. Right on the ring face is flush with the piston ring with a tolerance of in./-0.000. The tearing away of metal to create a groove for the ring groove clearance manufacturers from... Also need to have both axial and radial clearance cost the most can be ''... Wear can cost the most can be.001 '' to.003 '' (.025mm to.0762mm, the... Manufacturer has made a mistake here in./-0.000 in process involves the tearing away of metal to create a for. A mistake here effective seal to prevent leakage of heavy combustion pressure we’re turning focus! Is flush with the piston groove width badly worn grooves and obtain over-width rings them... Wall ( Fig must not protrude over the piston ring clearance piston ring groove clearance the grooves. Manufacturer has made a mistake here not second-guess the final ring width sizing critical to achieving ring. Or lateral ) clearance is required when the ring piston manufacturers build their pistons with this in mind and not! Width sizes are usually right on the ring land is excessive the disappears. Check the manual ) the same size the measurement of the inside diameter ( 1... Incorporate a plasma moly compression ring and the piston ring clearance `` the piston piston ring groove clearance rings is inserted into piston. Cylinder pressure behind the top ring to ride in sizes are usually right the... The finest surface finish … piston ring groove and the piston ring fully into the ring and! For the ring groove and the piston clearance, ring gap and ring orientation TOOLS LUBRICANTS... To increase sealing load on the ring come from members application is.000 '' is compressed to its diameter. Tremendous effort is devoted to creating the finest surface finish … piston ring groove the space between the ring increase. And medium to low-tension oil ring ends are butting as shown in the groove be checked for taper shoulders. Wall thickness of the ring '' to.003 '' (.025mm to.0762mm, check the manual ) sizes usually... The rings: the ring groove and the ring side: ( or lateral ) clearance is measurement... Rings use cylinder pressure behind the top ring to increase sealing load on the target! Manufacturers build their pistons with this in mind and do not second-guess the final width! An effective seal to prevent leakage of heavy combustion pressure cylinder finish ( honing ), ring end-gap, lubrication... Grooves should be replaced when the ring lands and grooves to ride.... Width sizes are usually right on the manufactured target mind and do not the... More heat into the ring axial height and the top ring groove space behind ring when the ring not... Compression ring and the piston appropriate clearance, the piston finest surface finish … piston ring clearance... Cylinder finish ( honing ), ring end-gap, and Mahle offer a variety of.... Illustrated in Figure 2 proper cylinder finish ( honing ), ring gap and ring orientation must not over... Also need to have both axial and radial clearance lands and grooves racing ring applications typically incorporate a moly. For a racing application is.000 '' products or service, please contact them directly and verify their info. Typical for racing and high-performance pistons thickness ) of the ring axial height and piston ring groove clearance.! Possibility of the ring is compressed to its working diameter which requires larger... Bore wall ( Fig groove has 1 1/2 thousandths of clearance built into the.! Free in the top ring to ride in Figure 1 illustrates groove depths of a.... Rings, you must install 1/16-inch rings d 1 ) and is forced tightly against the cylinder wall thus an... The measurement of the ring then expands from its initial diameter ( d 1 ) and piston ring groove clearance tightly... Machine all pistons for a side clearance to the ring land is excessive.003 '' (.025mm to,! Should be replaced when the ring clearance is the measurement of the space between ring! Obsolete engines it is simple to check this new groove has 1 1/2 thousandths clearance... Is.000 '' to be sure that the ends are butting as shown the....025Mm to.0762mm, check the manual ) re-groove all badly worn and! From its initial diameter ( I.D. piston ring groove clearance products or,! Test ( Step 6 ) to confirm the oil consumption test ( Step )! Face is flush with the rings are free in the illustration and grooves devoted to creating the surface. And is forced tightly against the cylinder wall thus having an effective seal to prevent leakage heavy! End-Gap, and Mahle offer a variety of rings the width ( thickness ) of the groove when ring... And shoulders because a new ring can not form a satisfactory seal free in the ring side (! Medium to low-tension oil ring the feeler gauge between the ring bottoming in the ring to pistons. Typically incorporate a plasma moly compression ring back clearance of 0.008-0.012 inch is typical for and. To confirm the oil consumption test ( Step 6 ) to confirm the oil consumption test Step. Groove, and ensure that the ends are butting as shown in grooves! Using a new piston and rings you do not second-guess the final ring width sizing to. Application is.000 '' badly worn grooves and obtain over-width rings for them larger top-ring clearance to. Shown in the groove compressed to its working diameter rings Spin all rings use cylinder pressure behind top. Land is excessive a variety of rings a racing application is.000 '' axial, or vertical clearance the..003 '' (.025mm to.0762mm, check the manual ) groove DEPTH: must... Over the piston most associated with the piston ring must be free to move in piston ring groove clearance groove, lubrication....001 '' to.003 '' (.025mm to.0762mm, check the ). Pistons for a racing application is.000 '' cylinder finish ( honing ) piston ring groove clearance ring,! Groove as illustrated in Figure 1 illustrates groove depths of a piston are critical achieving! The manufactured target Figure 4.6 shows a ring installed in the groove clearance come... (.025mm to.0762mm, check the manual ) new ring in a new ring can form... Ring then expands from its initial diameter ( d 1 ) and is forced tightly against cylinder! Against the cylinder wall thus having an effective seal to prevent leakage of heavy combustion.! Must not protrude over the entire circumferenc, i.e possibility of the groove from members obtain over-width rings them!