Gaskets, Oil Seals And Its Filter Functions In A Car Engine

Major Functions Of Gaskets And Oil Seals Filter In A Car Engine

The lubrication system is a very vital aspect of any engine. It is the bloodstream of the engine that makes it stay useable anytime. The system tackles lots of issues ranging from dirt removal, and temperature control, to wear and tear control.

Sometimes even new engines do contain small particles of metal leftover from the manufacturing process or grains of sand which have not been removed from the crankcase after casting.

Old engines continually deposit in the sump tiny fragments of metal worn from highly-loaded components such as the piston rings. If the substance is allowed to cumulative in the oil, the engine may develop major technical problems.

Hence, the oil filter helps the engine by removing those sucked particles from the stream of oil running inside the engine during operations.

Wire mesh strainer is the simplest part of the oil filter and it prevents solids from entering the oil pump. Some engines have an extra oil filter that traps very fine particles.

The most common type has a pleated paper or felt element and pumping oil through it removes all but microscopic solids from the lubricant.

Another way of separating particles is to pump the oil into a fast-revolving cylinder. The centrifugal force will then throw the particles to the outer edge while uncontaminated oil passes through the center.

Most engines use a full-flow system to filter all the oil after it leaves the pump. The most popular method is to pump the oil into a bowl or canister containing a cylindrical filter. From the inner walls of the bowl, oil flows through the filter and out from the center to the main gallery.

Full-flow filtration works well provided the filter is renewed at regular service intervals, leaving it for so long can cause a blockage. Blockage creates oil starvation to the parts of an engine during operation leading to a series of problems.

The built-up pressure of the oil inside the filter will forcefully open the spring-loaded relief valve in the housing and the oil can be forced to bypass the filter, this is a method employed to address any problem the blockage of the filter could result in the engine by ensuring the oil keeps flowing even when the filter has been blocked.

Meanwhile, the oil seals and gaskets play their own unique role in the lubrication system of engines. Since oil has the habit of creeping through small openings into areas where it is not wanted, oil seals and gaskets have been included in the engines to handle such situations.

A gasket is simply a piece of soft, oil-resistant material that is sandwiched between metal joints to prevent oil from seeping out. The gasket may be made of cork, a composition material, silicone-based compound that is squeezed from a tube.

Almost all the engines have a cork or composition gasket between the valve cover and the cylinder head. If oil leaks from this joint, it is possible that the gasket has been damaged during fitting, or is not properly located.

Many engine oil leaks from the valve cover are caused by the fixing nuts or bolts being over-tightened, distorting the cover by bending it into the soft gasket material. Straightening the valve cover and fitting a new gasket will stop any problem of leakages.

For parts where metal surfaces have to make close contact and yet provide oil seal, some car manufacturers specify a thin layer of mastic sealant on the mating surfaces. During tightening, any excess sealant is squeezed out, leaving a very thin film behind to prevent leakage.

Seals are necessary where the oil must be prevented from entering or leaving a moving component. The stems of valves at their upper-end work in an atmosphere where oil is continually dripped or squirted onto the camshaft or rockers that operate the valves.

It is important that excess oil cannot dribble down the valve systems into the combustion chambers because burning it will dramatically increase oil consumption.

The easy way of preventing such occurrence is to have oil seals at the valve stems. Depending on the engine, the seal may be in the form of a tight-fitting O-ring, an inverted mushroom shape threaded on the stem, or a spring-loaded to hold its sealing lip against the sliding valve stem.

All perform the same function because they deflect or wipe most of the oil from the valve stem to prevent it from being burned in the combustion chamber. A small film of oil does get through and lubricate the valve guides.

In the case where a rotating shaft protrudes from the engine, an oil seal is used to prevent oil from being thrown out. It is particularly important that oil does not reach the clutch linings and cause clutch slip, therefore, the rear of the crankshaft passes through some form of oil seal, where it emerges from the crankcase behind the flywheel.

Engines with road draught crankcase ventilation systems quite often use a scroll. It is a spiral groove machined on the crankshaft surface that works in a close-fitting housing and winds the oil back into the engine as the shaft rotates.

Frequently, a disc fitted to the crankshaft, on the engine side of the scroll is used as an oil thrower to spin-off excessive amounts of oil and prevent it from reaching the scroll.

With the increasingly widespread use of closed-circuit crankcase breathing systems, which can cause a small build-up of pressure in the crankcase, neoprene lip seals are more usually fitted to seal both ends of the crankshaft.

The lip seal is molded into a metal casing that is pressed into a register. At the rear of the crankcase, a recess is provided for the seal, and the soft lip around its inner circumference rubs against a machined face on the shaft.

The lip faces towards the oil, and then a circular coil spring around the lip acts like a rubber band and presses it against the rotating shaft.

Lip seals rely on making contact with a perfectly smooth moving surface in order to provide an oil-tight seal. Meanwhile, any damage to the rotating shaft surface will cause an oil leak.

The Importance of Quality Oil Seals for Transmission Rebuilds

Modern transmissions work hard, so shouldn't their oil seals do the same? Inferior seals are one of the most major diagnoses of transmission fluid leaks that can damage the unit beyond repair. When you're rebuilding transmissions every single day, it can be easy to forget how critical these small parts are, but in a system that operates under such high demands, the value well-made oil seals should never be underestimated. In today's post, we're here to discuss the importance of choosing quality when it comes to transmission oil seals.

Causes and Effects of Transmission Seal Leaks

A single transmission can contain dozens of sealing components, all with a specific purpose. If even one of those seals fails, the transmission in the vehicle can begin to leak transmission fluid. A transmission leak isn't simply an issue in itself, however; leaking seals can quickly lead to a multitude of other problems, including total transmission burn out.The purpose of an oil seal is to prevent lubricant leaks by closing in the spaces between a transmission's parts. The seals also prevent dirt and other contaminants from clogging up the unit. A static seal, such as a simple O-ring, fit between two stationary parts, while a more complex, dynamic seal has multiple lips and acts as a barrier between a stationary and a moving part.

Over time, due to varying pressures, stress, and heat inside a working transmission, seals will begin to break down — it's just a matter of time. However, depending on the quality of the seal, that time period can differ dramatically. Additionally, oil seals that accompany more active parts of the unit, such as the input and output shafts, experience a lot more wear and tear, and generally need to be replaced more frequently. And since several of these seals are located inside the transmission, they're tough to service without tearing apart the entire unit. Until a seal actually fails, it can be difficult to detect any sealing issues at all.

While proper maintenance and lubrication can aid in the longevity of an oil seal, seal performance is largely dependent upon the overall quality of the seal. Simply put, a poorly made oil seal cannot withstand the pressure fluctuations inside a modern transmission, and will cause more transmission leaks and issues in the long run. Therefore, it's important to choose the highest quality oil seals when rebuilding transmissions in your shop.

Quality Seals Under Pressure

To find oil seals you can truly depend on to hold up long after the rebuild is finished, there are a few key markers of quality you should be looking for. The material a seal is made out of is one huge indicator of quality. Cheap rubber seals don't have the same durability as more innovative materials like polyacrylate, ethylene acrylic, hydrogenated nitrile, fluoroelastomers, and more. Each of these materials has different properties that determine how they perform in different temperatures and environments.

Another true indicator of oil seal quality is its inclusion in the original unit as an OE component. OE seals for rebuilding are the exact same seals used by the original transmission manufacturer to build the transmission, so you can be confident that OE seals will have the highest level of performance as well as the best fit inside the unit.

While no oil seal can last forever, the quality of the seals you choose to install in your rebuilds affects not only the success of that job in the shop, but also the value of your work over time. Using well-made, high quality seals that are able to withstand the high demands of today's transmissions will only increase your productivity in the long-term.

Perfect Sealing Solution for Various Industries

What is an oil seal?

Oil seals are the key parts of mechanical equipment used in hydraulic systems, pumps, pistons, pipe connections etc. These are used to prevent the leakage of any lubricant and close the spaces between the moving and stationary components. These products are also known as shaft seals, fluid seals, grease seals, dirt seals, or rotary seals. These seals can stop any harmful contaminants from entering the machine in demanding environments. They also help to prevent the intermixture of two different mediums such as lubricating oil & water.

What are the general purposes of using oil seals?

An oil seal is designed to offer optimum sealing performance. Some of the major functions of oil seals are as below.

To stop the lubricating oil from oozing outside even at a very high pressure of the oil.
To protect every type of close-fitting, precision-constructed, sleeve and roller bearings.
To act as a barrier that keeps the lubricating oil in the right place.
To stop the contamination, dirt, and other external objects from getting into the system that contains the lubricating oil.

Construction of Oil Seals

Although there are various types of oil seals based on the application’s requirement, they all are made of three primary elements like rubber sealing element, metal case/reinforcement and garter spring. There are many materials used for oil or shaft seals that vary in resilience to the specific condition. These materials have properties that make them perfectly suitable for the required application. Metal cases/reinforcements of the seals are made of carbon steel or stainless steel based on the application which provides strength and rigidity to the seal. The metal surfaces exposed to the environment are treated to protect them from corrosion during normal handling and storage. The purpose of the garter spring which is located on the lip of the oil seal is to support the lip and prevent the leakage of lubricant and other contaminants from entering.

Sealing Materials

Oil or shaft seals are made from several materials based on the requirement of the application. However, the material selection is one of the important parameters considering several factors like operating temperature, environment, pressure, and maximum shaft surface speed, among others. The most commonly used materials in oil seals are Nitrile, Viton, Silicone, and Teflon which exhibit the below characteristics resulting in better life and performance of the seal.

Thermal resistance
Chemical resistance
Resistance to swelling
Weather resistance
Abrasion resistance

What are the applications of the oil seal?

The oil or grease seals are used in a wide range of applications in automotive, construction, agriculture, oil and gas industries, material handling, mining and so on. They are used in:

Engines
Conveyors
Elevators
Grinding Mills
Pipelines
Pumps
Wind Turbines

What are the benefits of Oil Seals?

The durability and flexibility of oil seals provide many benefits to different industrial applications:

Can perform under challenging weather conditions: Fluid seals can perform under challenging weather conditions. Be it high temperature or cold, they can perfectly serve for fluid environment applications.
Extended shelf life: Sealing materials like fluoroelastomer and PTFE makes sure that the fluid seals are durable and can be used for an extended period of time.
Low friction properties: These quality seals are built for low friction applications. The lubrication in the oil makes sure that the lips of the sealing do not reach the shaft and prevents the sealing lip from burning out.
Can be easily assembled: Assembling the shaft seals is also easy. You can easily replace these seals in a few minutes and for that, you don’t need to disassemble the entire system. These fluid seals come in a compact size, thereby handling and replacing them while you assemble are easier as well.
Lightweight: The fluid seals are light in weight and have the required qualities like strength and durability to work in demanding environments.
Can substitute standard seals: Oil seals can be used as a good substitute for standard or regular lip seals that are generally used for poorly lubricated or dry conditions.

How to choose the right Oil Seal?

Before you install a fluid seal, you must consider the type of application parameters within which it must function. This is important to ensure that you have installed the right seal. So while choosing the right fluid seal for your purpose, you should consider the below important factors. The designers and engineers of Sujan Industries ensure the below main factors before developing any type of oil or fluid seals:

Temperature
Shaft speed
Shaft hardness
Concentricity
Pressure
Lubricant
Runout
Shaft surface finish
Shaft and bore tolerances.

Keeping in mind these important factors will also determine the proper materials for building your oil seals. However, mistakes in the selection can result in total failure, premature wear, excessive internal pressure on the seal, cracks, lip hardening, swelling, etc.

And over time, this damage can lead to massive expenditure, specifically, if you overlook these issues and don’t address them promptly. However, selecting a proper profile for the application ensures optimum performance and a safe working environment for the upcoming years.