Lifespan of performance piston rings and bearings

[Poor King]

Resold a set of ARP headbolts because I was advised would not seal an un-resurfaced head properly. With that same thought process, would using performance gapless piston rings or racing main bearings with oem internals be a problem in longevity. I'm questioning the durability one would find from strictly using oem parts with stock internals for comparison to aftermarket piston rings and bearings on a very mild performance tune.

 

[Poor King]

No blowby and a higher intake mixture without a gap in the ring is very enticing...

GAPLESS DIESEL RINGS

Total Seal® extends its renowned Gapless® technology and performance into piston ring sets for the diesel engine ranks. With their extremely high cylinder pressures, the benefits of Gapless®rings for diesel engines are even greater than they are for gas.

www.totalseal.com

 

[Poor King]

Maybe I am overthinking this but I cancelled the resale of these bearings and retained them in hopes of reaching 400k just like the oem parts would for the ALH

 

[Mongler98]

What's wrong with the stock setup when they still get to 600k? Not good enough?
Solution in search of a problem this is.

 

[Poor King]

What's wrong with the stock setup when they still get to 600k? Not good enough?
Solution in search of a problem this is.

The stock stuff is good for stock power and the motor has a solid 400k. I am in terms of a full rebuild for it. It was up for a high powered build that is no more so I have these bearings laying around. So my question is why they would not be up for the task of 0-400k vs. the oem stuff with a mild increase in power?

As for the piston rings in question, new tech equaling to better combustion could only be a good thing, so I think. That is why I'm debating their overall durability if someone here has real world experience with a set.

 

[Poor King]

I found a credible video which states the gapless stuff needs shorter interval of replacement vs. oem stuff. So with that as proof, I will also not use the performance bearings.

 

[TDIMeister]

The OEM stuff are astonishingly good - maybe not specific to an engine code but rather if one is willing to research and dive into the VAG parts bin. Nothing has really come up as credibly superior alternatives when the balance of performance and longevity are simultaneously considered. Some aftermarket parts may come up better within a narrow performance definition for bleeding-edge applications (e.g. pistons) but compromise in other areas, e.g. piston slap - due to the lack of expansion rings, oil control and daily durability.

 

[[486]]

I haven't bought a fresh set of rings yet
figure the worn ones are a little looser for less drag and the end gap is usually pretty nicely opened up to where I want it so they don't butt if they get real hot

no reason to worry about a little blowby using up your combustion air, it's extremely easy to get more air in there than you can possibly use, especially without headstuds

 

[Poor King]

Ring tech in an ALH is a 20yo design so it was natural for myself to research if I am doing a complete rebuild. Plus a diesels combustion design leads me to believe that a complete seal during intake cycle would fair a better ignition cycle.. in theory. The gapless stuff has a marginal gain in combustion seal yet no one has done a gapless to conventional power gain test.

I know ring width (not inner depth) has been slimmed down to resist less drag and friction, while retaining the flexibility to continue a seal as the piston walks an expanded chamber. Many say that yesterday's F1 tech is today's oem ring technology. Nonetheless it seems that anything designed with performance numbers in mind, yields a shorter lifespan on daily driver applications. Not sure why but I'd like to know.

 

[Mongler98]

This thread is so much "wut" it hurts!
Rings in these engines, and for that matter all engines then and now (for the most part) is tech from 100 years ago. Not much has changed in the world of gapped spring steel.

 

[Poor King]

This thread is so much "wut" it hurts!
Rings in these engines, and for that matter all engines then and now (for the most part) is tech from 100 years ago. Not much has changed in the world of gapped spring steel.

Well your comment made me "lol wut".

Because I was debating Gapless piston rings. They are using a two piece system that conjoins to form a complete seal. Even that .02-.05 closed gap is showing marginal gain on intake cycle which imo is more air to combust that is being left out on the table. Also if installed properly, you can say goodbye to blowby issues in ho builds altogether.

I may not use them for daily purposes but racing teams are. While the conventional design of the piston ring may be quite old, whether it is the two piece concept of gapless rings or metallurgy of oem units, piston rings have evolved to resist higher friction and abuse generated from more powerful engines.

 

[TDIMeister]

The rings don't contribute anything to the intake stroke. Their main function is to seal under the highest pressures encountered in the cycle during compression and combustion.

 

[Poor King]

The rings don't contribute anything to the intake stroke. Their main function is to seal under the highest pressures encountered in the cycle during compression and combustion.

Without proper piston seal at all stages of an internal combustion, they would not perform at optimal levels. During an intake cycle when the piston strokes down, it draws air in. And without a proper seal it will accumulate less air in the chamber.

Fwiw, gapless offers a top ring half the size (thinner) of conventional rings. Not sure if any of you guys watch NASCAR, but the gapless ring tech came straight out of those engine shops.

 

[TDIMeister]

What you say is not incorrect, but any difference between, say, OEM and Total Seal rings are so negligible in terms of improving volumetric efficiency in the intake stroke as to be completely undetectable. If there is a benefit to gapless rings, they will definitely be manifest at the highest pressures encountered in the cycle, full stop.

As for declining ring thicknesses - both radial and axial - this has been a trend going on for years and is not limited only to the gapless kind. Besides, you can't put thinner rings on existing pistons and their fixed groove dimensions. Intuitively to me as an engine engineer, gapless rings are a good thing, but If they're so great and offer the claimed gains, I wonder why not a single major automotive OEM has ever used it when they are clamouring for every single bit of improvement for emissions and CAFE.

 

[Poor King]

I randomly fell onto the gapless products. Then watched a few indepth videos and parroted what was mentioned so I am clueless as anyone as to why they are not mainstream products. There are articles claiming 28 hp gains on sprint dirt cars. But I won't take the chance with the tdi build because they would be overkill; the same goes for the racing bearings. My gti build will definitely find a thin set of the gapless rings if I ever get to the R32 swap.