When did the piston ring/bore interface change?

[Stelth]

Not too long ago, in a VR&P thread, someone asked if VR&P would do any good on a '60's - '70's oil burning engine. The answer was given by someone, I forget who, who said that modern engines tend to burn oil because the rings are stuck, and older cars burned oil because the rings or bore was worn. Therefore VR&P isn't going to do anything for a '70's engine, for instance. I'm deliberately leaving out things like valve seals/guides etc., because I'd like to know if this is true.

I'm somewhat aware of modern ring and cylinder coatings. Do these prevent wear to the cylinder bore and piston rings? I haven't taken apart any modern engines, just an old 300 Ford, and a Datsun 2.0L. Also, can you rebuild these engines that have the specialized coatings? I know you can get coated piston rings, but what would you do to the cylinder bores?

 

[Jetronic]

It's not coatings, it's thinner rings that have less tension on them. it started gradually in the 80s

 

[Hohn]

Coated cylinders are difficult to impossible to rebuild. The coatings are just too thin. So if you have a nikasil or lokasil bores are essentially one-build only bores. You can't hone them without honing through the coating.

If I had an old engine I really wanted to save, I'd probably have it sleeved with a modern sleeve setup like the MID setup.

 

[02SE]

I've had numerous blocks bored and replated.

 

[Stelth]

So, would VR&P be worth trying on a 60’s, 70’s, 80’s engine?