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Hello everyone,,
Used to be everybody said run the thicker rings on the street and thinner in a race set up but modern "thin" rings like 1.2 or 1.5 mils will run for 200,000 miles according to Westech.
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They set up a 470ish hp small block with 5/64th's rings and ran it then swapped identically weighted pistons with 1.2 mil rings. With everything being the same from the oil to the dyno run engine temp, it made 8 more horsepower in the peak than the thicker rings. They also noticed that just turning the bottom end took 35 ft pounds with the thick rings and around 14 foot pounds to turn the engine with the thinner rings.
 

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Lessen the friction and HP will increase, Lessening friction also equals less wear.

Modern advancements in design, materials, and cylinder prep have circumvented the old school rule of thumb of using thick rings.
 

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No mention of it but I suspect low tension rings were also a factor. Unless they are assuming everyone knows thinner rings are low tension.
 

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Joe, the thinner stuff is supposed to be okay, but is it worth it ? In your example, it looks like you are getting less than 2% power gain. So, how much more do the thin rings and appropriate pistons cost ? In a 289 or a 302, you have the choices, but an extra $ 2~300 isn't worth it. I'd rather spend the money in other places. LSG
 

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I just can't picture how a thin will last that long. There going to be more flex and piston groove wear before it twist.
 

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I remember someone replacing all the crank bearing with roller bearings to see if it would increase HP. When completed, the initial torque to turn the engine was greatly reduced but when run on the dyno it showed almost no peak horsepower improvement over stock bearings. The thought was that once the engine was spinning that the crank turned didn't actually run on the bearing surface but on the thin film of oil supplied by the oil pump pressure, thus no improvement.
Rings may be a different story tho.
 

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I copied this from alldata.com. I think you need to match the ring type with a correct piston type. I have a 1999 4 cylinder Ford with 230000 miles and oil usage is almost nothing.

Difference between low-tension and ordinary piston rings
Low tension rings are thinner and exert less pressure against cylinder walls than conventional rings. This reduces friction, improving fuel economy and cylinder sealing. Low tension rings are used in most engines today.

Ring tension is described two ways. One is tangential tension, which is the amount of force needed to squeeze the ends of the ring together. The other is unit pressure, or the amount of pressure exerted by the face of the ring against the cylinder wall.

In the 70s, conventional piston rings had tangential tensions of up to 30 pounds. Compression ring tension specs for a Ford 302 V-8 used to be 22 to 26 pounds. It is 14 to 16 pounds on later model versions of the same engine. On some applications today, compression rings are rated at 5 to 7 pounds.

The amount of force the ring exerts against the cylinder wall (unit pressure) depends on tangential tension as well as ring thickness and cylinder bore diameter. Conventional oil rings exert pressures in the range of 180 to 240 psi. Low tension rings fall in the 90 to 160 psi range.

Most aftermarket low tension rings have a somewhat higher tension than the OE rings they replace. If an OE ring specification calls for 6 to 12 pounds, an aftermarket ring may have as much as 12 to 16 pounds. Higher tension is needed because rings are often installed in oversized cylinders. Cylinder bores may also have more distortion than a new engine, so extra loading improves sealing.

Low-tension rings require rounder cylinder bores, which may require the use of torque plates when honing certain engines. When heads are torqued, cylinder bores can distort up to 0.0015" or more near the bolt holes, throwing cylinders out of round.

This obviously makes it more difficult for rings to seal properly. Simulating bore distortion by bolting a torque plate to the block allows cylinders to be honed so they will maintain their shape when the engine is assembled.

It is essential that correct replacement rings be used. Conventional rings designed for standard grooves must not be used in shallow groove pistons designed for low- tension rings. Narrow, low-tension rings must not be used in deep groove pistons.
 
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