Piston skirt coatings, do they work?

[G_Body_Enthusiast]

I'm wondering if piston skirt coatings cut down on wear in the cylinders or it's just a bunch of hokum.

like these, http://www.summitracing.com/parts/slp-h ... /overview/

Obviously they're not expensive but are they worth getting over non coated pistons? I've never read an article that compared coated and non-coated pistons, that's why I'm asking.

Anyone with personal experience?

 

[Fox80]

It's not really about saving wear on the cylinder, it's about reducing the friction as the piston rides on the cylinder. The piston contacts the wall on one side on the way up, the other on the way down. The "piston rock" is inevitable the coating helps lessen the friction, heat, and power loss from it. Every race piston has it, for the relatively low price it's a good idea in a street motor. Stock style pistons have a much longer skirt so the gains in theory would be more so. You can find web articles on friction coatings, I read many of them as ciclre track motors use extensive friction coatings on various parts

 

[G_Body_Enthusiast]

I guess in theory then less friction would also means better gas mileage. I'm thinking about this since I have a street engine and there are plenty of stock style pistons with coatings and I'm thinking they might help with fuel consumption. If the engine isn't working as hard to rotate then that's more power moving the car. I imagine this is in small percentages, like it may improve your MPG by a point or two. Given how cheap the pistons can be, it sure wouldn't hurt to use them either way.

 

[MUELLERBU]

I would like to know how long these coatings last, especially after 20 min break in where friction, heat & break in would be at their respective peaks

 

[Fox80]

They last for a very long time, when the motor is new the piston rock is less because the bore is tight, and the ring to ring groove clearence is tight, as the motor wears and everything loosens up skirt contact becomes more prevalent. I dropped a valve in a brand new motor with 35 laps on it and when we pulled it down it still had the piston weight numbers on the skirts, written with a red paint marker. A 1,500 lap motor that is lapped out may have the coating slightly polished that's about it. I have thrown away many three turn piston sets away that the coating still looked good, so that 4,500 laps on a 8,000 rpm circle track motor. As far as fuel savings you may never know but anything that helps efficiency helps to contribute to better fuel economy, this falls in line with using a 1/16 ring pack on street motors the thin rings seal better and make less friction, but adds a bunch to the price of a piston. Read any race motor book the cylinder is the worst power loss area from friction

 

[MUELLERBU]

now that is the answer of all answers thank you

 

[pontiacgp]

anytime you can reduce the friction in the rotating mass it allows the engine to spool up quicker and in circle track that's a good thing.