Trying to learn, and see repeated references to the benefit of "modern ring packs". The obvious difference is thinner rings, but why is that better? Conforms better -->better sealing? What about coatings, such as DLC? Is there any reason not to use DLC coated rings in a street SBO aside from cost?

 

I would suspect less friction.

 

 

 

 

Anybody have real life, firsthand numbers on impact of changing from one ring to another? Almost everything I can find is manufacturer-provided. Curious if there is independent confirmation.

 

There are quite a few 358 builds with the Mahle 1mm ring pack. Coated pistons and rings. They did well on the dyno and supposedly make some extra power. My Pentastar has 1.2 mm rings. Modern engines use them for a reason, reduced friction equals horsepower and fuel economy.

 

The first video shows 18 hp gain. Granted, the video is posted on Total Seals YouTube channel, it appears the test was done by Shaver Racing Engines.

 

 

You need a machine shop that can produce the correct bore finish.

 

Someone posted an article Hot Rod Magazine about increased crankcase pressures with "skinny rings". This I interpreted as blow-by of the piston rings. "Blow-by" is lost horsepower from the combustion chamber ?

I believe Cutlassefi posted some dyno info that showed a small gain in horsepower with the "new modern ring packs".

I believe at one time, a piston manufacturer made pistons with 1/16", 1/16", 3/16" ring packs for racing. I don't recall who it was,. I am sure the new modern piston ring materials add to the sealing. For clarity, 1.5 mm = .059" with is close enough to 1/16" = .0625" to compare.
......Just my two cents worth.

 

The thin rings require a very specific bore finish to work well. How many shops are set up to produce the required bore finish?

 

Almost every engine I have actually assembled in the last 3-4 years has had newer "thin" rings. I just finished an old school 383 Chevy that has the old 5/64 5/64 3/16 ring pack and I actually pulled the first piston back out because of how hard it seemed to go in I wanted to be sure something wasn't wrong. Its amazing at how much more friction there is.

 

My short block turned over at 10 ft-lbs, curious how much that 383 took. Not a ton of miles but so far no oil consumption I can see. Plan on putting on way more miles next year.

 

Ring thickness has nothing to do with wall finish. It’s the ring material and/or the face of the ring that dictates that.
And there other points here that are being overlooked.

 

Does DLC coating a ring change the required bore finish?

 

Please share what the videos have overlooked?

 

Radial depth of the first and second rings and more so, oil ring tension are game changers as well.

 

The 1/16", 1/16", 3/16" ring packs were readily available from most suppliers in the later '60s and beyond as were 1/16", 1/16", 1/8" packs. We went to a .043" stainless, 1/16", 3/16" pack for the race engines in the mid 1970s. The .043" top ring was also available in a moly pack from Speed-Pro. As said previously by cutlassefi, ring type determines the hone used. Pic of the Speed-Pro attached.

 

Y’all are worried about the thickness of the top and second rings, that’s almost inconsequential. The bigger issue, as far as drag goes, is the oil ring.

 

Who ever said that. Its called a ring package for a reason and the gains are found as a package.

 

Were you running ring land spacers so that you could run the thinner ring pack or were the pistons made so that the thinner rings could be run?

 

Not necessarily true.
How many ring pack combinations have YOU personally tested? I’d be interested to know that.

 

I have only run conventional ring packages.
Does your machine shop that you use hone with diamonds or stones?

 

I bought pistons and rings from Mark. He specked 1.5-3.0 mm rings. He said the modern 1.5 rings are much thinner radially and will conform to the cylinder better. Also they are much lighter. So far I have had no issues with anything.

 

I ran .043-.062-3/16 in both stainless and moly in a 287” Chevy back in 1975 in my E/MP ‘67 Camaro. We would do a leakage test every time we ran it. Leakage was usually 4% after the first race on a new engine. Then we would pull it down an touch up the hone. After this, it would sometimes drop to 2% leakage. When it got to 8% it was time for rings. All the honing was done with deck plates and hot water running through the block. There seemed to be not much difference in the two ring materials except the stainless was a little harder on the cylinders.

 

A-B testing with ring packs is extremely expensive and time consuming since you're (almost always) also changing pistons. No one is going to do that just for their own entertainment. "Does it matter"? Probably not, but depends on the engine and how you use it. It's probably not worth buying a new piston and ring package if you're already done, but if you're starting a build then it's certainly a good idea to look for a lighter piston with a better ring pack.

Yeah, the hone finish isn't *THAT* special. It just needs to be a *GOOD* hone finish. The ancient rings were very forgiving and would simply chew away at the cylinder until everything was happy. Any shop with a good hone machine, two sets of good stones, and someone that knows how to use the machine can create a good finish. Using a profilometer lets you really tweak the finish, but it's really not necessary.

 

There is some good info here regarding cyl. wall finish and ring seating, the Gold book and Effect of plateaued cylinder wall finish are good.
Brush Research Manufacturing: Brush Literature

 

Stones.
Question, the metric ring packs typically use “lower tension” oil rings. How are they getting away with that without increased oil consumption? Hmmmm.

 

Bernhard, Only custom pistons for the race motors.

 

Good for you.

 

Sounds as though you have some knowledge. I am surprised you mentioned a profilometer, I was wondering if I was the only one who knew what they were.

 

that’s true… they’re putting words in your mouth as a gotcha.

ring packs are designed as a package for a reason.

 

it’s scary isn’t it? the scraping sound alone with the old rings is enough to make you grit your teeth and second guess yourself

 

I would say its not one factor.
Better heat transfer and reduced friction with a modern ring package
The second ring is a oil control ring first and a secondary compression ring The second ring is working well with the oil control ring in scaping off excess of oil
You have advancement in ring material. and coatings
Straighter cylinders and better metallurgy in modern engines.
Ring control is better because the rings are lighter and less prone to flutter at rpm.
Piston design has advanced reducing friction / heat. tighter piston to bore clearance can be maintained.
The thin rings conform better producing a better seal.
Advancement in oil, Thinner oils that perform better, reduced wear, less foaming, heat resistant, sealing ,heat transfer etc.
Because the first ring is sealing well you have less blow by this allows the second ring to do its job and puts less stress on the oil ring.
Modern oil ring design transfers essive oil back into the crankcase efficiently
Advancement in cylinder wall finish and measurement
Its a package.
I still remember engines developing piston slap/ rock at relatively low miles by todays standards. The tension, thickness and course face of the rings caused the cylinders to wear much quicker.

 

The rings in video are thin and have a smooth face that require a bore finish that holds oil.
What modern thin rings are coarse that do not require such a finish?
In the video they go to great length pointing out the importance of bore fishing and the ability to measure bore finish.
They also point out what is required and why its required.

 

Any moly faced ring requires the wall to hold oil, regardless of ring thickness.
And your previous post lists a few good reasons for maintaining good oil control with a lighter oil ring. But you still haven’t hit on the single biggest reason. Think ring pressure.😎

 

I have a 1963 Chevy 409 block on the boring machine right now. It is "standard" bore but is so worn at the top 3/4" that I don't think even .060" oversize is going to clean it up. Pretty typical for old engines.

The other thing that a lot of people don't think about is that Electronic Fuel Injection plays a huge roll in the longevity. Our old engines would start up with the choke closed and dumping a ton of fuel into the cylinders. And carburetors are always a compromise and usually on the rich side. Just that alone contributes to a lot of the wear. EFI engine only inject enough fuel to keep the engine running and not a drop more.

The only downside I see with modern ring packs is that they really do need a proper startup and quick break-in which most guys cannot accomplish. I wont build one without it going on the dyno to get started and broken in.

 

Really? Well ok, then explain this to us;
Hastings makes a lot of “ring packs” with one of two different second rings, either a reverse twist or a Napier. Many feel the Napier will give better oil control, thereby effecting the performance and dynamics of both the top and oil ring. Yet those rings are the exact same in both “ring packs”. Why?

 

FWIW I will be building a new short block for our dyno engine. It will have brand new Diamond pistons and rings. This is a "modern" ring pack and piston design. It will be tested back to back, along with some other very minor changes (mainly oil pan). I will report the results.

Mark is totally correct, you need the right finish but it's based on the ring material and material only. Livernois has a 7 figure hone that is probably the best hone in the world. Many places go there to have their blocks honed. Mine is already honed and ready to go. I MAY have results before the end of this month.

jerry