Piston Rings

G

guru

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Mar 25, 2008
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Is there a piston ring selection guide anywhere?

In any case, I am looking for the best deal on piston rings for a 7000rpm 355 chevy with 11 - 11.5 to 1 compression.

I am leaning towards some speed pro moly faced economy rings part# R8902

A moly faced cast iron top ring, a standard second ring and a standard tension oil control ring.
 
Hey man, Justin likes the gapless rings, he swears by them, however, in reading there's different schools of thought on that.
 
Yeah he does, he likes the total seal gapless top rings.

If someone could demonstrate what I get for $260 bucks that I am not getting from a $90 dollar set of moly faced speed pro rings, I would be all about it.

Total seal claims 6" more vacuum and more HP.
 
guru said:
Yeah he does, he likes the total seal gapless top rings.

If someone could demonstrate what I get for $260 bucks that I am not getting from a $90 dollar set of moly faced speed pro rings, I would be all about it.

Total seal claims 6" more vacuum and more HP.
Click to expand...

Let me know what your research uncovers, interested in the answer.
 
What I see is a cult following.

1.) Some people swear by them and have a lower leak down
2.) Most engine builders who are willing to speak on the subject say they havent seen a power or racing advantage either way
3.) The magazines are saying a horsepower gain in the single digits on a 500hp motor

the only back to back test I can find conviently was an old article called danger mouse.

http://www.popularhotrodding.com/en...2em_small_block_chevy_engine/small_block.html

http://www.superchevy.com/technical...etebuilds_testing/0406sc_dm22_copy/index.html
 
If you look at the way pistons are made today as most of them have an extra groove between the first and secaond ring which is called a pressure seal grove or a accumulater goove, Which allows pressure to build up between the first and second groove, Now if pressure builds up between those 2 rings it will lift the top ring off the ring land in turn will cause poor ring seal.

There are a lot of engine builders out there that open up the ring gap on the second ring to get rid of any gasses between the rings.

Gapless rings only work good on a leak down test and may hurt performance when the engine is running.

We leak down our circle track engines and after a season of running and nothing is hurt we only see 1.5 to 2% leak down with no gapless rings.

Your biggest gain would be make sure the block is plate honed using the same head gasket and hardware that is going to used during the final assembley.

I have seen guys spend money on file fit rings and no plate honing which was a big wate of money.

We have leaked down new engines where they were not plate honed and seen up to 16% leak down.

A good set of file fit Speed Pro, JE and Mahle has some good ring packages as well.

Here is an interesting link on plate honing.
http://www.camaros.net/forums/showthread.php?t=58964
 
Ive had MIXED results , using gapless rings vs standard rings,
and Ive found the condition of the surface of the cylinder , the care taken durring the assembly, the piston, design and the use of a hone with a deck plate , durring the hone process and the grit used and angle of the hone job all effect the power results more than swapping from standard to gapless, rings, also keep in mind the brand and type of rings does effect results
 
What makes file fit better?

Sounds like Speed Pro R9771 would be a darn good choice then.
 
"What makes file fit better?"

the ability to EXACTLY fit EACH ring and its gap,too the differant bore dia. of each cylinders bore , no matter how consistant the machinist, the bores do vary , very slightly between cylinders, so no pre- fab ring will allow you to exactly match the ring gaps, BUT,ID also point out that it allows you a good potential to screw up the rings if your not careful.
in most cases the pre-gap rings are fine, but if your looking for that last bit of hp, and want to go thru the effort necessary the file fit have a slight potential advantage
 
Last edited:
grumpyvette said:
"What makes file fit better?"

the ability to EXACTLY fit EACH ring and its gap,too the differant bore dia. of each cylinders bore , no matter how consistant the machinist, the bores do vary , very slightly between cylinders, so no pre- fab ring will allow you to exactly match the ring gaps, BUT,ID also point out that it allows you a good potential to screw up the rings if your not careful.
in most cases the pre-gap rings are fine, but if your looking for that last bit of hp, and want to go thru the effort necessary the file fit have a slight potential advantage
Click to expand...

When we hone bores we don't seem to have a problem with bores varying you may want to find a better shop to do your work:lol::lol:
As we don't seem to have that problem with sizing cylinders.

If we plate hone a block per say to .030 we don't we have a junk block we honed .030 with out a plate and fit the rings to that cylinder as we have a couple of junk blocks that have different size not plate honed cylinders.

If your fitting rings to cylinders that have been plate honed and when torquing the heads the cylinder will become round and open up the ring gaps. Some times we will file fit rings to a cylinder with the torque plate still torqued down on the block to make sure they are round when fitting the rings. If its a cylinder size we don't have in one of our junk blocks.

On 010 or stock OEM blocks we see more distortion then we do in a Dart or Bowtie blocks.
 
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