How to choose the right wear ring for your application

Author admin When it comes to choosing the right wear 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 wear ring for your application.

Mechanical requirements for wear rings: pressure, speed and lubrication

The most important factor in the selection of wear 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? Wear 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 wear rings in question. Wear 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 rod or cylinder from wear.

Wear ring shape and dimensions

Wear 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. Wear 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. Wear 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 wear rings

The world of plastics has an especially wide range of materials. Not all of them are suitable for wear rings though. Additives are also required to specifically optimize the material properties for use in wear 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 wear 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. 

How to choose piston rings

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Post by frnkeore » Sat Jun 01, 3:17 am

If you want to learn more, please visit our website Dongya.

So not to high jack the 5/64 vs 1.5mm ring thread, I thought I'd open this one, to maybe get more details on how and what works, for different applications.

This ring thing, is very confusing.

I think I understand that a thinner ring with have less friction but, there are so dam many thin rings now. This is a list of the ones I know about:
.9mm = .
1mm = .
.043
1.2mm = .
1.5mm = .059
.
.
., still used in some old OEM applications

There are also different materials:
gray iron
ductile
steel
SS

And there are many face contours, as well as plating's, you can add to that gas ported rings, too. That for the upper two rings and then you have lots of options for the oil control rings, in both width and tension.

The first two things I would like info/opinions on is gas ported rings and low tension oil rings. When is gas porting needed and how low can you go with low tension oil rings w/o a vacuum pump?

Re: How to choose piston rings

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Post by mag » Sat Jun 01, 7:22 am

In terms of gas porting I think the preference is now to use half moon grooved in the top ring land.
There far less likely to load up and clog off, but I guess you need more of them then the round hole type due to the reduction in area. You can cut a man's tongue from his mouth, but that does not mean he's a liar, it just shows that you fear the truth he might speak about you!

Re: How to choose piston rings

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Post by Lizardracing » Sat Jun 01, 2:07 pm

I choose the piston first, then the rings for the block material, hose to ring manufactures spec. That's per Total Seal instructions to me.

Re: How to choose piston rings

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Post by frnkeore » Sun Jun 02, 12:19 pm

I was hoping for more input on this subject so that I could have, at least, good, better, best options to choose from but, more than that, I think it's info that most high end engine builders would have strong opinions on and before laying out money for pistons, I have to spec a ring for them.

Also, I was hoping to get some general info on directions to go, that could have a good cost/benefit ratio, if not for me but, for others, in selecting rings for their applications.

In hopes of getting some specific info, for my build and what rings would be best, here is what it is:

4.280 bore x 4.100 stroke
1.550 CH, 18cc dish
aluminum
0.000 deck clearance x .040 head gasket

This engine has 350 cfm heads and is cammed for to rpm.

At the moment this is the ring set I'm considering, unless I can find something better.

Hastings SM 4.28 - .043 Steel, .043 Duc/Nap, 3mm 11 lb Oil

What are your thoughts?

Re: How to choose piston rings

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Post by Walter R. Malik » Sun Jun 02, 1:46 pm

What and how rings are chosen and used has everything to do with the end usage of the engine to be built.
Using something normally used in a high horsepower, high RPM engine would be totally wrong in a grocery getter rebuild ... and visa-versa.
AND, then there is all those engines built "in between". http://www.rmcompetition.com
Specialty engine building at its finest.

Re: How to choose piston rings

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Post by frnkeore » Sun Jun 02, 6:30 pm

Walter R. Malik wrote: 'Sun Jun 02, 1:46 pm What and how rings are chosen and used has everything to do with the end usage of the engine to be built.
Using something normally used in a high horsepower, high RPM engine would be totally wrong in a grocery getter rebuild ... and visa-versa.
AND, then there is all those engines built "in between".

So, at what point would you use gas ported pistons, in a NA engine?

Also, in what kind of build would .9 x .9 x 2mm be an advantage over what I'm considering?

How low of oil ring tension, can you use with exhaust evacuated crank case?

Re: How to choose piston rings

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Post by Walter R. Malik » Sun Jun 02, 6:57 pm

Are you interested in learning more about Piston Wear Ring? Contact us today to secure an expert consultation!

frnkeore wrote: 'Sun Jun 02, 6:30 pm

Walter R. Malik wrote: 'Sun Jun 02, 1:46 pm What and how rings are chosen and used has everything to do with the end usage of the engine to be built.
Using something normally used in a high horsepower, high RPM engine would be totally wrong in a grocery getter rebuild ... and visa-versa.
AND, then there is all those engines built "in between".

So, at what point would you use gas ported pistons, in a NA engine?

Also, in what kind of build would .9 x .9 x 2mm be an advantage over what I'm considering?

How low of oil ring tension, can you use with exhaust evacuated crank case?

I will tell you what I have found but, it is certainly not to reflect the "be all, end all".

Gas ports tend to make the rings wear faster, (the thinner the ring, the faster they wear), but, do give slightly more power to the engine; your choice as to what is most important in THAT engine.
They are almost necessary with .043" thick radial dimension rings; unless you are seeking longevity.
Otherwise, they are usually most power effective for me when using fatter, back-cut rings in shallower grooves.
The best quality of thin rings is their conformability to the bore.

I have run 3/16" oil rings as low as 7 pounds fish scale drag with ATF, leaving a whisper of oil residue in the chamber without a crankcase air pump.

Anything else, I usually do whatever the ring manufacturer wants. http://www.rmcompetition.com
Specialty engine building at its finest.

Re: How to choose piston rings

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Post by Warp Speed » Mon Jun 03, 10:10 am

Walter R. Malik wrote: 'Sun Jun 02, 6:57 pm

frnkeore wrote: 'Sun Jun 02, 6:30 pm

Walter R. Malik wrote: 'Sun Jun 02, 1:46 pm What and how rings are chosen and used has everything to do with the end usage of the engine to be built.
Using something normally used in a high horsepower, high RPM engine would be totally wrong in a grocery getter rebuild ... and visa-versa.
AND, then there is all those engines built "in between".

So, at what point would you use gas ported pistons, in a NA engine?

Also, in what kind of build would .9 x .9 x 2mm be an advantage over what I'm considering?

How low of oil ring tension, can you use with exhaust evacuated crank case?

I will tell you what I have found but, it is certainly not to reflect the "be all, end all".

Gas ports tend to make the rings wear faster, (the thinner the ring, the faster they wear), but, do give slightly more power to the engine; your choice as to what is most important in THAT engine.
They are almost necessary with .043" thick radial dimension rings; unless you are seeking longevity.
Otherwise, they are usually most power effective for me when using fatter, back-cut rings in shallower grooves.
The best quality of thin rings is their conformability to the bore.

I have run 3/16" oil rings as low as 7 pounds fish scale drag with ATF, leaving a whisper of oil residue in the chamber without a crankcase air pump.

Anything else, I usually do whatever the ring manufacturer wants.

What portion of the ring is wearing faster due to gas ports?

Re: How to choose piston rings

• Quote

Post by Walter R. Malik » Mon Jun 03, 11:00 am

Warp Speed wrote: 'Mon Jun 03, 10:10 am

Walter R. Malik wrote: 'Sun Jun 02, 6:57 pm

frnkeore wrote: 'Sun Jun 02, 6:30 pm
So, at what point would you use gas ported pistons, in a NA engine?

Also, in what kind of build would .9 x .9 x 2mm be an advantage over what I'm considering?

How low of oil ring tension, can you use with exhaust evacuated crank case?

I will tell you what I have found but, it is certainly not to reflect the "be all, end all".

Gas ports tend to make the rings wear faster, (the thinner the ring, the faster they wear), but, do give slightly more power to the engine; your choice as to what is most important in THAT engine.
They are almost necessary with .043" thick radial dimension rings; unless you are seeking longevity.
Otherwise, they are usually most power effective for me when using fatter, back-cut rings in shallower grooves.
The best quality of thin rings is their conformability to the bore.

I have run 3/16" oil rings as low as 7 pounds fish scale drag with ATF, leaving a whisper of oil residue in the chamber without a crankcase air pump.

Anything else, I usually do whatever the ring manufacturer wants.

What portion of the ring is wearing faster due to gas ports?

The face and the bore itself is what I have witnessed.

I am talking about 10,000 street miles instead of 25, 000 or more. http://www.rmcompetition.com
Specialty engine building at its finest.

Re: How to choose piston rings

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Post by jsgarage » Mon Jun 03, 2:58 pm

For poor boys that want to freshen up an existing combination of still usable pistons with wider grooves instead of buying all-new pistons for some size of new thin rings, there are several companies that now make flat steel spacers to resize wider piston grooves for thin rings, ported or not.

They likely will not work quite as well as pistons specifically cut for a thin ring and it introduces more complication in engine assembly, but they're a cheaper way of trying the concept out, maybe for several different thickness of ring in your engine combo and ascertaining any extra face wear.

Re: How to choose piston rings

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Post by Walter R. Malik » Mon Jun 03, 4:37 pm

Clicked on the wrong subject. http://www.rmcompetition.com
Specialty engine building at its finest.

Re: How to choose piston rings

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Post by frnkeore » Mon Jun 03, 5:23 pm

jsgarage wrote: 'Mon Jun 03, 2:58 pm For poor boys that want to freshen up an existing combination of still usable pistons with wider grooves instead of buying all-new pistons for some size of new thin rings, there are several companies that now make flat steel spacers to resize wider piston grooves for thin rings, ported or not.

They likely will not work quite as well as pistons specifically cut for a thin ring and it introduces more complication in engine assembly, but they're a cheaper way of trying the concept out, maybe for several different thickness of ring in your engine combo and ascertaining any extra face wear.

Can you list the company's and/or web sites?

Re: How to choose piston rings

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Post by Roundybout » Mon Jun 03, 7:31 pm

For more Piston Ring Manufacturerinformation, please contact us. We will provide professional answers.

I know Total Seal makes a spacer to be able to use thinner rings in pistons with grooves meant for thicker rings. 1.2mm" or .8mm" rings in 5/64 groove or .8mm" rings in 1/16 groove for example.

Not sure how I like that idea long term or as a solution though. Ring flutter and not a true representation of what a thin ring can and can't do for you. Not to mention just more crevices for things to hide and carbon up. Don't know how that would react to piston ports either. I think they are mainly used for classes where standard width piston grooves are required or some other silly rule.