What piston rings should I use?

allcarfan said:

well, the pistons i have wont fit my pistons. I need a suggest for piston rings. The engine is naturally aspirated, makes about 475 hp and is a 331. Im not particular on any kind of brand....but i see cast, vented, moly, etc type rings...and I have no idea the benefits or drawbacks of any of them. i am also on a budget as most of us here are.

Shane

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Depends, what are your intentions for this motor?

-Plain cast iron rings are the quickest to break-in, which also means they are more likely to wear and break sooner than chrome or moly. Probably best suited for a stock motor with no real special parts, i dont think cast rings would be your best bet.

-Chrome rings are especially suited for engines that will inhale alot of dust and dirt. ie: dirt track car, off-roading, or just a car that is in a unsually dusty or dirty enviroment. Chrome rings are very tough and strong and last longer than cast and moly rings in these conditions.

-Moly rings in my opinion are the best bet you can choose for piston rigns. They have a much better life span than the chrome and cast rings, and they require virtually zero break-in miles. They advantage of a moly ring over the other two is that a moly ring carries more its own oil as the piston goes up and down, giving you better protection. It has surface voids, or little depressions which collect oil. Cast and chrome rings have almost no voids and must depend almost souly on the cross-hatching of the cylinder wall to supply lubricating oil.

With cast and chrome rings when the piston gets to the power stroke the cylinder wall is exposed to a burning fuel charge, and the oil that is on the wall is partially burned away, so your rings will not receive their full amount of lubrication for the trip back up the cylinder on the exhaust stroke. Moly rings also provide there own lubrication that is not directly exposed to the combustion process.

Hope this helps you decide

One side-effect to the different surface characteristics of ring materials is that the finish on the cylinder wall should be matched up to the ring material.

Ie. if the ring carries a lot of oil, the xhatching doesn't have to be as deep and vice versa.

Hack said:

One side-effect to the different surface characteristics of ring materials is that the finish on the cylinder wall should be matched up to the ring material.

Ie. if the ring carries a lot of oil, the xhatching doesn't have to be as deep and vice versa.

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I forgot to mention that, thanks But any reputable machine shop should know this, and if they didnt i wouldnt take my stuff there