How to choose the right piston ring for your application

When it comes to choosing the right piston ring, the devil is in the details. Slot design, fixing groove depth and width, and material all play an important role in the performance and lifetime of the component. In this blog post, we'll fill you in on what you should consider when selecting the right piston ring for your application.

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Mechanical requirements for piston rings: pressure, speed and lubrication

The most important factor in the selection of pistons rings is the pressure (force per area), which acts on the rings in the application. But frequency and speed of movement also play a major role. The type of lubrication and the coefficient of friction should be taken into account too. But why are these values so important?

Piston rings that are exposed to high pressure should be made of the most resistant material possible. Self-lubricating fiber-reinforced plastics or steels are commonly used here; however, they have the disadvantage of being heavier and requiring constant lubrication.

Speed of movement also plays a role. Depending on the material used, if the product of speed and pressure is too great, the resulting frictional heat cannot be sufficiently dissipated without additional lubrication.

The type of lubrication depends on application requirements and the technical characteristics of the piston rings in question. Piston rings made of plastic or plastic fabric are often self-lubricating. Solid lubricants such as PTFE or molybdenum sulphide (MoS2) minimize coefficients of friction and protect the piston rod or cylinder from wear.

Piston ring shape and dimensions

Piston rings can be mounted in two ways. They can either be fitted on shafts or rods or installed as guides in cylinders. This is why guide rings are slotted -- to provide the necessary clamping force and flexibility.

Piston rings also serve as a sealing function or are designed to let lubricating or hydraulic oil through (depending on the shape of the slot). There are also angled and straight slots or form-fitting variants with a Z or tooth profile. Piston rings made of plastic offer the advantage of less complex shaping since plastics can be processed and machined relatively easily and cost-effectively.

Material variety for piston rings

The world of plastics has an especially wide range of materials. Not all of them are suitable for piston rings though. Additives are also required to specifically optimize the material properties for use in piston rings. In addition to improved properties such as elasticity, coefficients of friction, and mechanical stability, the materials differ primarily in their temperature resistance, thermal expansion, and chemical resistance.

The properties mentioned above, mechanical strength and elasticity, maximum PV values, and thermal properties can be compared especially well by means of data sheets. But what do they say about component durability and service life? Here the comparison is often difficult. Design programs and formulas, like our plastic bearing service life calculator, can help here. 

For assistance choosing the right high-performance plastic piston ring for your application, contact us here or call us at (800) 521-. You can also learn more about our maintenance-free iglide bearing materials here. 

Piston clearances are crucial to engine efficiency and longevity. Therefore, when purchasing and installing new rings, it is necessary to be aware of the piston ring fitting and clearance. There are many different places where you can buy the best circlips. But before you buy, you need to know a few things about how to fill in the blanks.

Ways of Choosing the Rings

Anyone with basic engine knowledge knows the importance of starting an engine for the first time. The successful start of an engine largely depends on the initial ignition of the engine. It also ensures that the engine lasts as long as possible, delivers maximum power, uses the highest efficiency and lasts as long as possible.

It is not possible to test all engine structures. However, it is very important to understand how the piston rings are installed and spaced correctly.

Making the right choice is only possible by knowing what type of piston ring is available. You should also be familiar with what the piston rings do.

Piston rings perform the following functions:

• Sealing of the cylinder
• Oil control
• Transferring the heat to the cylinder walls

Efficiency of Engines

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Heat transfer from the piston to the cylinder is fast and efficient. Choosing the right piston rings is crucial when it comes to performance driving. Depending on how your engine is used, the choice you make will vary.

Pistons come in different varieties:

• Casting piston
• Forged piston
• Supra-eutectic piston

To choose a piston ring, you must know what type of piston you have. In addition, you should consider the piston rings. Only in this way can you use your engine at maximum efficiency.

How Is Ring Gap Measured?

The first step is to place each ring on the corresponding cylinder. The ring must be square in order to fit properly in the hole. This procedure includes placing the ring in the hole and then squaring it with a squaring tool.

Cavity meters are generally used to measure cavities. Ideally, if you start with large 0.005-inch rings, there will be no gaps between the rings and there may even be some overlap.

Piston Ring Assembly: How to Bleed Piston Rings Properly?

Generally, two methods are used to attach the rings. These methods are not limited to engineers and engineering professionals. Other people can also wear them by rolling them.

The basic technique when installing a ring is to keep the ring in place. For this, a slight pressure is applied on the ring, minimizing the deterioration of the ring. This will allow you to accurately space the piston ring.

Oil ring expander assembly should begin with the instructions on the package or included in the package provided by the ring manufacturer. Extenders should not overlap. They also need to be carefully rolled.

You should minimize distortion in the circlip assembly and prevent damage to the ring. This way, you can be sure that the procedure is well done and appropriate.

Errors When Filling the Segment Gap

Not measuring gaps

Rings are sometimes considered pre-cavity and ready-to-install. However, there is a greater-than-normal gap tolerance between rings produced by ring manufacturers. You have to make sure that each ring is placed on the cylinder you want to place and is measured similarly. This ring needs to be kept with the roller throughout the entire process. In some cases the rollers are slightly different. That's why you have to be consistent when wearing the rings.

Not looking at the manual provided by the manufacturer

Data provided by many ring suppliers are based on OEM ring spacing only. You should make sure it has the proper ring clearance for the piston ring you are using. Because materials and applications differ significantly. Therefore, the manual provided by the manufacturer should be consulted.  

Putting the rings in the wrong direction

There is a certain orientation for 99% of all top and second ring sets. Bevels, twisted veneers, etc. Numerous things make the rings faceted.

Both the first and second ring usually have a lettering or a dot indicating which side is up. You must consider the shape and function of each ring to know how the rings should be put.

Contact us to discuss your requirements of Piston Ring Exporter. Our experienced sales team can help you identify the options that best suit your needs.