piston coatings

[slasky]

I am putting my common block 2.5 together and just bought some venolia forged pistons. My friend suggested that I get them coated on the sides and top. I think I will go with the Teflon coating on the sides but I don't know if I should have the tops ceramic coated. I am concerned about what is going to happen to the heat that is reflected. Is it going to damage the heads or valves? Will it make the engine more prone to pre detonation? Anyone have experience with this?

Thanks

[Andre Parker]

If you have the piston tops coated, get the valves and combustion chamber coated as well. It will make your car less prone to detonation. I would get a moly based side coating as teflon will shed oil and moly will hold it and reduce friction. I have my own engine coated as well as another one Wallace and I are working on. It's good stuff.

[slasky]

I was just guessing that it was Teflon. I will see what this guy uses to coat the sides. He is a friend of a friend. He is some kind of chemical genius that invents his own coatings and has some unique secret way of attaching it to the pistons. My friend had his LT1 motor pistons coated and picked up 40 hp. Some of that was from his new computer but some of it had to come from the coatings.

[turbovanman]

I am also considering getting my pistons coated. I have read that the coating on the crown does reflect to much heat into the chamber and causes more detonation. I will not be coating my cylinder head. Anyone have any info, or actually coated pistons-did it make it more detonation happy??????

[slasky]

I spoke to the guy that does the coatings and he said he has people running high boost with just coating the pistons. He said that the detonation occurs at the sharp edges of the pistons; like valve reliefs. The coatings insulate and distribute the heat so it does not get concentrated at these points. He does also offer coatings for the combustion chamber, valves, and exhaust ports.
I will be coating my pistons but not the head yet. I figure that I could always do the head later if I need it. The guy seemed very confident that I would be OK with just the pistons. Besides I just dropped a ton of cash on the new pistons, cometic head gasket, ARP head studs, machine shop, and $42 a piston for coating is about all I have left to spend on this car!!!!

[turbovanman]

Cool, thanks, well let us know how it works out,

[The Riddler]

there is another comapny that does coatings... http://www.swaintech.com/

my friend used them on his turboed neon. He swears by them.

[slasky]

That's the company that is doing mine. I just dropped them off today. They are only aboput 15 miles from my house.

[neon_steve]

Slasky,
Keep me posted on how you make out with Swaintech, I am down here in Corning NY, about 90 miles from you, and have a new set of Ross's that will be going in a 2.5 this fall/winter. I don't think I want my tops coated, but would be interested in getting the sides coated. I may be talked into the tops though ;-) Could you email me your contact there so if I talk to someone they will be slightly familer with the application?

Thanks!
Steve

[Andre Parker]

If you are going to coat the piston top, then you should do the combustion chamber and the valves too. The coating is a reflective type and it actually reduces your motor being prone to detonation. You reflect the heat back into the combustion and not into the part which can cause hot spots on sharp edges. You get more bang for the buck. The dry film lube is good to use on skirts, cams and bearing surfaces. I have my motor coated in my Daytona and Wallace and I have a motor that is fully coated. Even the intake and exhaust runners in the head.

[slasky]

I am just getting the pistons coated for now. I hope to get a ported head at some point and then I will have it coated as well.

[Reaper1]

Yeah, I'm interested to know how that Swaintech does for you too. I had some JE pistons coated a few years ago by them with the Gold Coat on the tops and the Moly stuff on the sides. I was not able to put them in the engine for a long time(as a matter of fact I still have them in a box), but the Gold Coat turned green and sticky! I was told by a rep from Swain that they should have been put back in the bags they came from when the machinist got done with them to prevent moisture from getting to them. This did not happen, and the end result was the coating turning bad. Now, their explination for this is that the Gold Coat is such a high temp material that they can't cure it all the way with the pistons out of the engine. They can only cure it to something like 70%, and then as soon as the engine is started the first time the high combustion heat cures it the rest of the way....sounds kinda fishy to me and I'm not quite certain I beleive it 100%. At any rate it cost me something like $35/piston and it is ruined until I can send the pistons back to them to have them recoated(and I have to pay for it again! ). I HAVE seen their TBC(Thermal Barrier Coating) in person on a set of Porche 911 turbo headers. VERY nice and the guy said that underhood temps did slightly decrease with it, but that it was the cool-down time he was impressed with. He said that after a hard run you could wait 45min or so and touch them with your hands! To me that says volumes! One last thing. I know another TD'er that runs the Gold Coat in a TIII engine with a longer rods...he loves the stuff...and no, he doesn't have the heads coated. As a matter of fact even Swain told me that unless the engine was for a pure race application that doing all of the other coatings would net negligable gains. Anyways, yeah, I want to know how it works out for you too!

[Stratman]

The guys that did mine "Polydyn" are located in Houston, TX and do the Iroc and Winston Cup cars. $33 a piston including the dry film lubricant on the skirts. Keep in mind guys that the side coatings make the piston around a .001" larger and if you have a good finished cylinder already within the clearance that the piston manufactures allow before you decide to get the coatings, you will have to tidiously rub some of the coating down with special super fine abrasive cloth untill you knock enough to get some of your clearance back. It took me about a week in my spare time to rub mine down to where I felt comfortable.
It is a good thing to coat the pistons and then have the cylinder work done to include the clearance of the coatings, (that is if you have a good enough machinist to get that close, and if not, find another). Here is a page on my stuff that got coated. Click the link on the bottom to look through my site and there will be more on the subject elsewhere. Click here for the Heat Coatings page

[slasky]

Those pictures look great! My Engine needs to be rehoned because I was going to use mahl pistons originally and now I bought the Venolias. My machinist wanted to wait until after the pistons were coated to see what the final size would be. I am also having him enlarge the hole in the block so it matches the oil pump and I am also having it balanced. I there anything else I should have him do while the engine is apart?

Thanks.

[Stratman]

Quote:

Originally Posted by turbovanman I am also considering getting my pistons coated. I have read that the coating on the crown does reflect to much heat into the chamber and causes more detonation. I will not be coating my cylinder head. Anyone have any info, or actually coated pistons-did it make it more detonation happy??????

Hi Turbovan,
When I was talking to the owner of the coating business, he said I would need to lower the timing about 2-3 degrees due to the heat reflection. And yes, the knock sensor does seem to pick up more knock voltage than before with the same calibration and is really fuel happy, BUT, this is a different motor configuration than before, so, one can't assume that just the coatings are responsible for doing this.