Thread: Pistons. Coated or uncoated???

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Just wanting to hear oppinions on the teflon coating on pistons. I have never used any on the teflon coated pistons and am getting ready to stroke a couple of LT1s. Seems to me that the coated pistons would be better for friction, but I am concerned about the longivity. Has anyone ever used the pistons over an extensive periond of time and mileage, and how do they hold up?
Stands to reason that if the coating flakes off that it would get into the oiling system and who knows. Also I am concerned that it the coating wears or flakes off that it would cause more than desirable piston to wall clearance.
In my stock LT1s that I have, both at least 150,000 miles, you can still see the hone markings in the cylinder walls and the machine grooves on the pistons show hardly any wear at all if any. Not bad for over 150,000 miles. I might add that these engines came out of Police cars. They also sit and idle for hours on end that doesn't show up on the speedo.
What,s your thought on this?

Thanks, Ed

If you want to reduce friction, run 'em loose. Coatings are for reduced cylinder wall wear, they won't have a noticeable effect on horsepower. They do work and durability isn't a big issue if properly applied. Just about every new car rolling off the production line today has moly coated piston skirts.

When did they start using coated piston skirts in production cars? Both of the LT1s that I am working on have a machined hyper piston.

Ed

speed pro coats there skirts to run them tight or teflon buttons in racing to cut the drag this was a old trick we just run them loose there as been many advancement in the alum and the skirts so if you are asking if i would do it for a all out engine yes i would think about it .have used many of the coated pistons but have never look at them after i put them in and i never run them at the min piston to wall coated or not but with the coating you can run them abit tighter i put them in the mid point

Originally Posted by Hurst01

Just wanting to hear oppinions on the teflon coating on pistons. I have never used any on the teflon coated pistons and am getting ready to stroke a couple of LT1s. Seems to me that the coated pistons would be better for friction, but I am concerned about the longivity. Has anyone ever used the pistons over an extensive periond of time and mileage, and how do they hold up?
Stands to reason that if the coating flakes off that it would get into the oiling system and who knows. Also I am concerned that it the coating wears or flakes off that it would cause more than desirable piston to wall clearance.
In my stock LT1s that I have, both at least 150,000 miles, you can still see the hone markings in the cylinder walls and the machine grooves on the pistons show hardly any wear at all if any. Not bad for over 150,000 miles. I might add that these engines came out of Police cars. They also sit and idle for hours on end that doesn't show up on the speedo.
What,s your thought on this?

Thanks, Ed

In the old dirt mod. we tried the Mahle coated pistons.
We pulled the engine down after about 17 nights some on the "coating" was still on the pistons and some was gone in a very strange pattern.
It almost looked like someone had sanded a few spots here and there.
This was maybe five years ago.
Maybe things have changed?

i was running mahle coated pistons in my mustang before i blew the engine... had about 25k on the motor pistons looked perfectly fine.... ran a few nights on the track with it but mainly on the street..... if only the rods had looked as good as the pistons afterwards

I am seeing a lot of the coated pistons for sale. I just don't know if I want them or not, especially when I see a late model Chevy small block that is approaching 200,000 miles and doesn't show any significant signs of wear. Of course an aftermarket piston may not wear as well, I don't know. Back in my younger days I have seen engines come down with less than a thousand miles on them that looked like the pistons were almost worn out.
As of right now I don't see how you could do better than a stock Chevy hyper piston. Problem is that I want to build a couple of 383 small blocks which changes things a bit. Not to mention that a full set of pistons from GM would cost a bunch more than aftermarket pistons would. Can anyone tell me how the newer aftermarket hyper pistons wear?

Ed

they wear fine unless you have detonation.... on a newer computer controlled motor you shouldn't have detonation though because of knock sensors and such.....

pistons should not wear like you like you think here are some things that will work the skirts not breaking the edge at the bottom of the bore this cuts the skirt. no tq plating the block on some engines .runing the engine to hard with to small of clearances to the wall .over heating the engine. valve train parts washing in the oil geting on the shirts . je / ross/ mahley all make a fine piston and if you follow the what i out line you will be fine 200.000 on some thing your are racing? no the rpm is not the same as a stock engine but they should not just fall out