Engine gaskets and seals are crucial components in any vehicle, ensuring that fluids, such as oil and coolant, stay where they're supposed to be and prevent leaks that can lead to engine damage. Understanding these components can help you maintain your vehicle better and address issues before they escalate. This guide covers everything you need to know about engine gaskets and seals, including their types, functions, and maintenance tips.
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Engine gaskets are thin sheets or layers of material that provide a seal between two engine parts, preventing the leakage of fluids and gases. They are designed to fill the space between two or more mating surfaces, usually to prevent leakage while under compression. Gaskets can be made from a variety of materials, including rubber, metal, cork, and more, depending on their specific application and the demands of the engine.
Engine seals are designed to contain fluids within the engine and prevent them from leaking out, as well as to keep contaminants out of the engine. Unlike gaskets, which are used between stationary components, seals are often used around moving parts.
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The integrity of engine gaskets and seals is vital for the performance and longevity of your engine. A leak in any of these components can lead to:
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Engine gaskets and seals play a critical role in the health and efficiency of your vehicle's engine. Understanding their function, types, and how to maintain them can help you prevent costly repairs and extend the life of your engine. Regular maintenance and prompt attention to any signs of leakage can keep your engine running smoothly and efficiently.
Introduction:
Oil seals, also known as radial shaft seals or shaft seals, are indispensable components in hydraulic pumps and motors. Their primary function is to create a barrier against fluid leakage and protect against contaminants, ensuring the efficient and reliable operation of hydraulic systems. In this blog post, we will delve deeper into the world of oil seals, exploring their design, reasons for failure, and best practices for selecting and maintaining these critical sealing elements.
Section 1: Understanding Oil Seals
Oil seals are cylindrical-shaped seals designed to fit around rotating shafts, sealing the gap between the shaft and the stationary housing. They typically consist of three essential parts:
Outer Case: The outer case is usually made of metal or elastomeric material and serves as the housing for the sealing element.
Sealing Element: The sealing element, often made of rubber or other elastomers, comes into direct contact with the shaft and forms the primary sealing interface.
Spring: Some oil seals feature an internal spring to maintain constant contact between the sealing lip and the shaft, ensuring an effective seal.
Section 2: Reasons for oil seal Failure
Several factors can contribute to the failure of oil seals in hydraulic pumps and motors:
Contamination: Exposure to abrasive particles, dust, and debris can cause wear on the sealing lip, compromising the seal's effectiveness.
High Temperatures: Excessive heat generated during operation can degrade the sealing material, leading to loss of sealing performance.
Fluid Compatibility: Using incompatible hydraulic fluids can cause the sealing material to swell, shrink, or deteriorate, resulting in leakage.
Shaft Runout: Shaft misalignment or excessive shaft runout can lead to uneven wear on the sealing lip, causing premature failure.
Improper Installation: Incorrect installation practices, such as using improper tools or not ensuring proper lubrication during installation, can damage the oil seal.
Section 3: Selecting the Right Oil Seal
When choosing oil seals for hydraulic applications, consider the following factors:
Operating Conditions: Assess the operating temperature, pressure, and speed to select an oil seal that can withstand the specific demands of your hydraulic system.
Material Compatibility: Ensure the selected sealing material is compatible with the hydraulic fluid and any potential contaminants in your system.
Seal Design: Choose the appropriate seal design based on your application, such as single lip, double lip, or V-ring, depending on the level of contamination and sealing requirements.
Quality and Brand: Opt for high-quality oil seals from reputable manufacturers to ensure reliability and longevity.
Section 4: Maintenance and Installation Best Practices
Proper installation and regular maintenance are essential for the optimal performance and longevity of oil seals:
Ensure Cleanliness: Prioritize cleanliness during installation to prevent the introduction of contaminants that could damage the seal.
Use Lubrication: Apply a compatible lubricant on the sealing lip during installation to reduce friction and prevent premature wear.
Regular Inspections: Include oil seal inspections in routine maintenance to identify signs of wear or damage and replace seals as needed.
Conclusion:
Oil seals are vital components that contribute to the efficiency and reliability of hydraulic pumps and motors. Understanding the factors that can lead to oil seal failure and selecting the appropriate seal for your specific application will help optimize the performance and extend the life of your hydraulic system. By following best practices for installation and maintenance, you can ensure your oil seals effectively protect against fluid leakage and contaminants, making your hydraulic equipment operate at its best for years to come.
Sealing device design is an intricate art, and at its heart lies the delicate dance of O-ring compression and tension. The journey through O-ring seal groove design is a crucial exploration, where the balance between too little and too much compression can make or break the success of a sealing device. Join us in unveiling the principles, considerations, and secrets behind mastering the art of O-ring seal groove design.
The Compression Ratio (W) is the cornerstone of effective O-ring seal groove design. Striking the perfect balance between sealing the contact area, minimal friction, and avoiding permanent deformation is an art. Discover the intricate considerations that guide compression rate selection for static and dynamic seals, understanding radial and axial sealing nuances.
Delve into the impact of O-ring stretching on sealing performance and service life. Uncover the formula for Tensile Strength (α), exploring its significance in achieving the perfect amount of stretch for optimal O-ring functionality.
Understand the critical role of contact width in O-ring deformation after installation. Learn how the width of the contact surface influences sealing performance and service life, balancing between too small and too large for optimal results.
Embark on a journey through groove shapes, from the widely used rectangular groove to V-shaped, semi-circular, dovetailed, and triangular variations. Learn the advantages, applications, and design principles behind each groove shape, unraveling the secrets of optimizing O-ring performance.
Dive into the intricate calculations behind groove width and depth, understanding the volume considerations and the importance of leaving ample space for compression, expansion, and adaptability to dynamic movement. Gain insights into designing groove widths that balance friction resistance and wear.
Explore the impact of groove wall roughness on O-ring sealing and groove processing. Uncover the distinctions between static and dynamic sealing requirements, ensuring the right surface finish for optimal performance.
Discover the crucial role of retaining rings in boosting O-ring performance under high pressures. Unravel the advantages of different retaining ring materials, with a spotlight on PTFE’s precision, chemical resistance, temperature range, and friction characteristics.
Navigate the world of practical applications, understanding when and how to employ retaining rings based on pressure conditions, directionality, and potential friction considerations. Learn how retaining rings elevate O-ring performance while preventing detrimental phenomena like “gap bite.”
As we conclude this comprehensive guide, it’s evident that the O-ring seal groove design is a blend of precision, science, and art. Mastering these principles empowers engineers and designers to create sealing devices that stand the test of time. Elevate your understanding of sealing excellence and embark on a journey towards mastery in O-ring seal groove design.
Oil Seals
May 03,
An oil seal is basically a simple device, which is used to stop dirt, dust, water, and other contaminants from entering the shaft equipment. It is also known by other names like elastomeric lip seal, lip seal, shaft seal, or rotary shaft seal. The seal, while doing its job, helps retain the lubrication of a rotary shaft equipment. These seals are mainly used to protect the bearings used in a rotating shaft.
Materials Used to Make Oil Seals:
Oil seals can be made from a vast range of materials depending upon the application. Some common materials used to manufacture oil seals include:
Silicone: The widest range of operating temperature range is provided by silicone compounds. They offer an amazing temperature range from -90°F to 340°F. Nonetheless, in dry running conditions, these compounds do not perform well. It is always advisable to avoid the usage of silicone compounds with oxidized oils and EP (Extreme Pressure) compounds.
Viton®: Viton® compounds are said to offer the widest operating temperature range varying from 40°F to 400°F. These are considered as the premium materials for the lip seals. In addition to this, these compounds are highly resistant to chemicals and abrasion. These qualities help Viton® deliver better good performance. Unlike silicone compounds, Viton® performs well in dry running applications.
Nitrile Buna-N: Most companies consider Nitrile Buna-N 70 durometer compound to be the perfect material for oil seals. The compound has several benefits, which makes it the first choice of material in a wide range of applications. Oils seals that are made from this material have a wide operating temperature range from -65°F to 250°F. In addition to this, this material is compatible to work with water, as well as common mineral oil and greases.
Above mentioned are some materials used for manufacturing oil seals. Each material has its own set of pros and cons. Therefore, selection of materials should be made on the basis of the application. There are quite a variety of materials to choose from. If you find it tricky to select the right material for oil seals, you can always ask an expert. SSP Manufacturing, Inc. is one such expert in manufacturing oil seals in the USA. Please contact us by : +1-888-238- or with any questions.
Oil seals are found in a wide range of applications, in virtually every industrial sector. It is essential to select the correct oil seal so that the application in which it is used can run efficiently, free of leaks or other issues. In this blog, we explain which factors you should pay attention to when selecting the best oil seal for your application.
The group of oil seals used in dynamic applications include radial shaft seals that seal a rotating shaft around its circumference. They are also known as lip seals, but in this blog we will use the term oil seals.
Usually, these oil seals are used to seal lubricating oil or grease and contain it within the application, so that moving parts such as bearings are continually supplied with enough lubrication. However, such seals are also used for sealing other liquids, gases, and solids, such as powders or granules.
An oil seal consists of:
An outer case, a body made of metal or provided with a rubber layer
A rubber or PTFE sealing lip
A spring, the composition of which depends on the type
The lip is specially designed to ensure the oil seal works effectively with the different forces that arise during rotation. Many different designs and materials are used, so countless types of oil seals are available. These are chosen according to the application; pumps, gearboxes, wheels, and many other rotating applications where fluids need to be sealed. They are used in a variety of sectors, such as the chemical industry, manufacturing, wind turbines, automotive sector, food industry, and more. Oil seals are used in nearly all sectors.
What should you take into account when selecting an oil seal? Different types of oil seals and various types of materials are available, each designed for specific uses. It is also important to select the right size of oil seal for the best results. For this reason, selecting the right oil seal requires adequate understanding of the application in which it will be used.
Most standard oil seals have to comply with the DIN and ISO standards. Different standard types of oil seals are available that comply with these requirements.
The most common oil seals are the ERIKS types R, RST, M and MST, which correspond respectively to types A, AS, B and BS according to DIN /ISO .
DIN
Standard /
ERIKS
DIN
A
Standard /
Rubber covered
ERIKS
R
DIN
AS
Standard /
As type A with dust lip
ERIKS
RS
DIN
B
Standard /
Metal cased design
ERIKS
M
DIN
BS
Standard /
As type B with dust lip
ERIKS
MS
DIN
C
Standard /
Double metal cased
ERIKS
GV
DIN
CS
Standard /
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As type C with dust lip
ERIKS
GVST
All are fitted with a spring to preload the sealing lip. All these types are for non-pressurised or low-pressure applications up to 0.5 bar for diameters of a limited size. For diameter of 500 mm or more, the maximum pressure is 0.1 bar. For higher pressures, special types or PTFE lip seals can be used.
ERIKS type M (type B according to the DIN standard) has a single metal casing and rubber sealing lip. Since the casing is made of metal, it must be fitted in a well-finished, undamaged groove. Large volumes of oil seals with metal casings are often cheaper, which is why they are often used as original equipment in machines. However, if an oil seal has to be replaced, types with a rubber exterior (type R or RST) are easier to fit. Type MST is similar to M and commonly used. The difference is the dust lip in the MST oil seal that prevents dust and dirt reaching the sealing lip, and extends its service life in dusty environments.
ERIKS type GV (type C according to DIN) is equivalent to type M, but is a heavy-duty version with a double metal casing. This can be a useful solution with larger diameters in more demanding applications. There is also a version of this type with a dust lip; the GVST (type CS according to DIN).
ERIKS type R (type A according to the DIN standard) is identical in shape to type M, but has a rubber outer case with metal reinforcement on the inside. The rubber creates a good seal in the housing, even if the housing has suffered minor damage or is not in its best condition for other reasons. The RST version has a dust lip. These types are often chosen to replace a type with a metal outer case because they are easier to install and can cope with minor damage to the groove, such as scratches.
ERIKS also supplies the types GR and GRST. These are virtually identical to the types R and RST, except in this case the metal inner ring is also completely encased in rubber. ERIKS uses FKM rubber here as standard, so these seals are ideal for use in acidic environments.
An overview of the different standard types of oil seals and their main characteristics is shown below.
In addition to these standardised types, the following special types are also available:
Rubber oil seals with a rubber fabric outer case
These are comparable to type R and RST, except the outer case does not have a metal reinforcement ring. To compensate, the outside is not made of normal rubber, but a hard, heavy-duty rubber fabric. The advantage is that these types can be made in a split version. They are almost always produced to order, and made of NBR or FKM.
PTFE Lip seals
These types are made with a metal outer case and a PTFE lip. They are suitable for a wide range of temperatures from -90 °C to +260 °C.These lip seals can also be used for higher pressures of up to 10 bar (special types up to 25 bar) and rotational speeds of up to 40-45 m/s. Certain grades of PTFE are suitable for use in pharmaceutical and food applications. One important point is that PTFE lip seals do require a shaft with a harder, smoother finish.
Cassette Seals
Cassette seals are designed to maximise grease or oil retention and protection against liquid or solid contaminants. These seals are provided with their own bushings in which dirt is kept out and oil/grease kept in by a multi-lip seal.
These cassette seals are widely used in wheel-end applications, such as the axles of agricultural machinery or off-road trucks.
Oil seal for higher pressures
The sealing lip of the RST-D is more heavy-duty, so it can cope with pressures of up to 10 bar at slightly lower rotation speeds.
Reinforced GVP design for larger diameters, with rotation speeds of up to 15 m/s and pressure of 3-4 bar
Outer case
Metal
The metal used in the outer case of oil seals is usually made of carbon steel. Upon request, and depending on quantities, a different type of steel (such as stainless steel) can be used.
Rubber or rubber fabric
The quality of the rubber or rubber fabric used to make an outer case is the same as the quality of the rubber sealing lip. Fabric reinforced rubber is, as the name suggests, rubber reinforced with a fabric.
Spring
Standard springs are made of carbon steel. We use stainless-steel springs for our GR and GRST oil seals made from FKM rubber. In some rare cases, an O-ring is even used as a spring element. Standard PTFE lip seals are not fitted with springs.
Sealing lip
The sealing lip is always made of a rubber or synthetic material. For oil seals with a rubber outer case (R, RST, GR, GRST), the rubber quality of the sealing lip and the outer case are the same.
The material of the sealing lip is chosen according to the liquid to be sealed and the rotational speed. For larger shafts, an NBR sealing lip can cope with surface speeds of up to 10-12 m/s, while an FKM lip is suitable for speeds of up to 35-38 m/s.
Nitrile Butadiene Rubber (NBR, nitrile)
NBR, also known as nitrile rubber or nitrile, is the most popular material for an oil seal because of its good resistance to many oils and greases, such as mineral grease and hydraulic oil. Depending on their composition, synthetic oils and greases, such as those based on glycol, can damage NBR rubber materials. Depending on the amount of glycol, a PTFE lip seal may be the best choice. NBR is also unable to cope with contact with acids and solvents. The rubber is suitable for oil and grease at temperatures from -35 °C to 100 °C.
Most ERIKS oil seals, such as the types M, MST, R and RST, are made of NBR as standard.
Fluorine rubber (FKM, Viton™)
FKM or FPM, which is in well-known brand Viton™, can withstand higher liquid temperatures of up to 180 ˚C. FKM is highly resistant to strong acids and bases, as well as to synthetic oils and greases. Glycol-based oil and grease, however, can also damage FKM.
Because of the higher temperature resistance of FKM, this material is also chosen for applications where higher speeds play a role, which raise the temperature at the sealing lip considerably. Usually, using FKM will result in a longer life than using NBR. This compensates the higher price of FKM compared to NBR, as an FKM does not have to be replaced as frequently. The low temperature resistance of standard FKM is limited to -15 ˚C.
Polytetrafluoroethylene (PTFE, Teflon®)
PTFE, which is used in the well-known brand Teflon®, is less commonly used, but it is the preferred material for specific rotating seals in the chemical, food and pharmaceutical industries. This material is notable for having a very low frictional resistance and the best chemical resistance. It can also withstand a very wide range of temperatures in these types of seals; -80 ˚C to 200 ˚C. The shafts on which oil seals with PTFE lips are used require a harder and finer finish. Something like an axle sleeve can also be used to meet this requirement.
EPDM
EPDM oil seals are less common. They are used in solvent, hot water and steam applications, EPDM resists low temperatures down to -50 °C and UV radiation well. Some types of EPDM are also suitable for higher temperatures up to +150 °C. EPDM oil seals are usually available upon request.
VMQ (silicone)
VMQ, also known as silicone, is also used for oil seals, but this is less common because the mechanical strength of VMQ is low and this material has poor wear-resistance This makes it less suitable for dynamic applications, but it can withstand fairly low and high temperatures from -60 °C to 200 °C. Many types of VMQ are also suitable for contact with pharmaceutical and food products, so VMQ is an option worth considering. VMQ oil seals are usually available on request.
Rubber type
Material Code ISO
Heat resistance
Rubber type
Nitrile
High wear resistance good running properties for general use
Material Code ISO
NBR
Heat resistance
-35 °C to + 100 °C
Rubber type
Polyacrylate
Better heat, oil and chemical resistance than NBR
It is recommended for use in oil which contains load bearing additives such as EP gear oils
Material Code ISO
ACM
Heat resistance
-20 °C to + 130 °C
Rubber type
Viton®
High level of chemical resistance
High temperature resistance
Material Code ISO
FPM
Heat resistance
-15 °C to + 180 °C
Rubber type
Silicone
Wide temperature range
Commonly used in low temperature applications
Very prone to mechanical damage during fitting
Material Code ISO
MVQ
Heat resistance
-50 °C to + 150 °C
Rubber type
Polytetrafluoroethylene
Chemical resistant
Low coefficient of friction poor elastic properties not wear resistant if used by dynamic applications
Material Code ISO
PTFE
Heat resistance
-80 °C to + 200 °C
Rubber type
Leather
Recommended for abrasive applications
Good running properties, due to the impregnated seal lip
Can be used on shafts which have a surface roughness outside the range for rubber seals
Not suitable for water
Material Code ISO
-
Heat resistance
-40 °C to + 90 °C
Oil seals are available in an immense range of sizes, for shafts from a few millimetres to several metres. Once the shaft diameter, groove diameter (housing diameter) and groove width are known, selecting an appropriate oil seal is a simple task. An oil seal or its product description is usually associated with three dimensions, for example 6x15x4. These refer to the sizes of the hardware for which the oil seal is designed. In this example, this oil seal is suitable for: 6-mm shaft diameter x 15-mm groove diameter x 4-mm minimum groove width.
Have you found the right oil seal for your application? The next step is fitting the oil seal correctly, so that it remains undamaged.
Before fitting the oil seal, it is essential to check that the oil seal, shaft and bore are clean and undamaged. The surfaces the oil seal will come into contact with must be free of sharp points or burrs. The sealing lip is fragile, so even minimal damage can cause a leak. It is also important that the shaft and bore are correctly finished.
To install an oil seal properly, the shaft must be undamaged. This is so the oil seal can do its job properly on the one hand, and to prevent it from being damaged during fitting on the other. In addition, it is very important to lubricate the shaft, the sealing lip and the bore with plenty of grease. This will allow the oil seal to slide more easily over the shaft and prevent dry running after the first rotation. The oil seal may also come into contact with the keyway, thread or other grooves when sliding over the shaft. By taping or covering the shaft at the location of these irregularities with oil-soaked paper, the oil seal can be mounted without damage to the sealing lip.
Other important factors are ensuring the hardness and roughness of the shaft are correct. A shaft hardness of HRC 45 is recommended for a rubber sealing lip, with a roughness of Ra 0.4-0.8. A higher shaft hardness of HRC 60 and shaft roughness of Ra 0.1-0.4 is recommended for a PTFE lip.
Always start by making sure the oil seal is facing the right direction. The oil seal must be positioned with its spring to the side of the medium to be sealed. The oil seal must then be pressed into the bore. It must fit tightly (H8 in the groove is recommended). Use appropriate tools for this, such as an impact socket set, to ensure that the force is applied evenly during pressing. The oil seal must never be hammered into the bore with brute force, but eased in.
See here for more information and useful fitting tips.
Stijn de Cnop
Product Manager of Sealing & Polymer Technology
Product Manager of Sealing & Polymer Technology
Replacing a critical component can be difficult to get right, especially if you do not have the original machine specifications. Thankfully, there are a few ways to identify oil seals; from their design, size and material. As there are hundreds of different oil seals available on the market, this guide will cover the four most common design types. Typically available with either a single or double lip, in Nitrile or Viton Rubber Material.
Firstly, the oil seals covered in this guide classify the single lip as the inner diameter at the bottom of the component. The single lip is vital to the function of the seal by containing the oil, grease or lubricant. The only difference between a single and double lip is the additional rubber lip on the top of the oil seal which helps prevent dust or dirt from coming close to the shaft. Identifying the oil seal lip can be misinterpreted with a visual inspection alone. For or this reason, you should press along the inner diameter at the top of the seal, if you feel a ridge with a slight movement or give it is highly likely you have a double lipped oil seal.
Industry retailers use unique codes to identify oil seals worldwide. The most common lip style designations are 21 (single lip) and 23 (double lip), please read our Oil Seal Cross Reference Guide for more detailed information.
Fully covered outer diameter for excellent sealing. This oil seal is fully enclosed in a rubber material and is the most widely used type of oil seal. Great resistance to thermal cycling, temperatures and different chemical resistance.
Economic metal outer diameter for standard applications. This is an economical oil seal where the metal is exposed on one side and offers a closer fitting between the oil seal and housing or bore. Due to this, it has limited use with sealing thin liquids or gases.
The same design as type B with an additional inner case for greater structural rigidity. This type of oil seal is typically used in heavy-duty engineering machinery or large diameter sized seals
The same design as type A with corrosion protected metal case and stainless-steel garter spring. Suitable for use with a wide range of fuels and chemicals.
Nitrile or NBR is black in colour, whereas, Viton or FKM is usually a brownish colour. To understand the main comparisons between the two compounds read our Nitrile vs. Viton article.
Finally, Polymax part codes follow the same pattern as our O-rings - inner diameter, outer diameter and height. This is different from the industry-standard convention, whereby imperial oil seals follow - outer diameter, inner diameter and height.
We hope the information in this article helps you identify the correct oil seal for your application. If you have any queries feel free to call one of our sales engineers on . Polymax stock over 6,000 oil seals available to buy online, browse our oil seal selection today.
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