I don't know if its just me but the coating on my new Wiseco Turbo Pistons is rubbing off. Is it a break in coating or is it supposed to last a while? I can take the stuff off with my finger nail. I also noticed that it's very easily scratched. I'm a little worried and if it's not supposed to be like this, then I'm very pissed. Does anybody have any clue on this?

First time using these pistons and I'm a little worried. Though I have read most manufacturers are starting to put break-in coatings that help with startup and help with piston / ring failure.

 

The part of the coating that does the work is the part that's embedded in the aluminum.The coating that you see rubbing off is the visual hp producer.

 

So are you saying its there for looks? Visual HP producer?

 

Yup.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Tbone &raquo;</TD></TR><TR><TD CLASS="quote">
#2 for all you that are going to say it wears off.
IT"S supposed too on the skirts, the proper way to run these coatings is to actually buff it down to the point on non visibilty, Coatings facilitys wont do this because the customer wont think the coating was done if they cant see it. After a few hundred miles most Moly coatings will visually wear off a piston and you wont see it anymore. The coating is bonded with the metal so even if you cant see it, it's still their doing its job.</TD></TR></TABLE>

from this thread: https://honda-tech.com/zerothread/1051325

 

So I guess expert engine builders are supposed to automatically know this... then again, because I'm an expert I do things more than once so when I took the piston out, I pretty much crapped my pants... First I thought maybe I had some dirt in there (which I may have), doing a much cleaner job next time. Second I thought maybe somehow I had a tapered bore and they we're being pressed into the walls towards the bottom (not so)... I guess for most people they'd never notice as they assemble the motor and it's done. So I could buff off that coating if I wanted? How COULD I go about doing so? (Just to be devils advocate).

 

Seems silly to me. We don't suggest the coatings because it changes the piston to wall clearance after the motor runs. Another thought on coating the tops of pistons as well. I guess some do this to keep the heat in the chamber. But if the tune-up is off that much that it would melt a piston, I personally would rather see it do just that then keep the heat in the chamber and have it mess other parts up like the cycl. head.

 

I appreciate all the replies... It does seem like a pointless endeavor. Maybe they get more emails if it's not "noticable." They still got an email from me . I already went with a .0035 clearance over the spec'd .0025 to account for the stock sleeves and higher boost i'm going to run. Though after buying these pistons I found out that my engine would come to 8.4:1 compression.... Guess I'm going to have to advance that timing in part throttle and ramp up the boost. I guess now that this coating will wear off I'm looking at .004 which is acutally what I was going to run but Jim Justice said I'd be fine with .0035 so thats what we decided on. No biggie, mo' protection for me.

 

The best way to do it is to set the piston to wall clearance before the coatings, or buff a small portion of it off to get a get a reading on the piston w/o the coating. I coat the pistons on all the motors i build.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by tony1 &raquo;</TD></TR><TR><TD CLASS="quote">The best way to do it is to set the piston to wall clearance before the coatings, or buff a small portion of it off to get a get a reading on the piston w/o the coating. I coat the pistons on all the motors i build. </TD></TR></TABLE>

So then the motor runs tight until the coating wears off? And what if the coating does not wear off? Also, how can you control how much it will wear off? Seems like specs would be uncontrollable like that?

 

The coating on the sides will come off on your hands from rubbing it. There's no "run tight until it wears". It all comes off the skirts, it's what's imbedded in the piston that makes it work. It's not like they're spraying some unknown substance on the piston. On top of that, we're not talking about .010" or anything. You might see .001" on the skirts, that WILL go away after startup. Piston coating is nothing new, and it wouldn't have been around as long as it has and be as widely used in motorsports if it required a guess at clearances.

 

To me, .001 thou is a lot of clearance change to not be in control of. I guess the only way to use them is to wipe off the coatings then before the pistons are measured. The way a wall on the CP is made, it retains oil. I guess wiesco does not use the same technology as CP when it comes to skirts. Are they coating to save on wear or is it to help contol oil?

 

I subscribed to this thread because it might be the only new thing I learn today.

 

I know after all of this next time I'll know better and go with CP pistons. Everyone will have different experiences with this. Glad you can all share with this. I'll take pictures of my pistons just to show what kind of problem I'm dealing with.

 

From Calico's website.

CT-3 Coating:
Dry film lubricant that retains oil while reducing friction and heat. The CT-3 Coating allows for the use of tighter clearances without scuffing, resulting in less blow-by increased horsepower and less wear on cylinder walls and piston rings.
Application: Piston Skirts

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by tony1 &raquo;</TD></TR><TR><TD CLASS="quote">From Calico's website.

CT-3 Coating:
Dry film lubricant that retains oil while reducing friction and heat. The CT-3 Coating allows for the use of tighter clearances without scuffing, resulting in less blow-by increased horsepower and less wear on cylinder walls and piston rings.
Application: Piston Skirts</TD></TR></TABLE>


Every company has to make money by selling product. If you can buy a piston that does not need to be coated, why not just do that?

I have used 1 set and sold 1 set of Calico coated bearings and we went with their suggestion of "tighter clearance" and I can say I will never use their coatings on bearings ever again.

 

Of course they don't NEED to be coated. No piston NEEDS to be coated, but that doesn't mean that there's not an advantage to doing so. Do you think DFL coatings and thermal coatings don't work?

 

I do not see a need to coat a piston that proper clearance's were used and tune up is correct. This of course I am speaking about is for CP pistons. With Wiseco, maybe they do benefit from coatings?

I prefer metal treatments then to just coating metal.

 

isnt coatings that offer thermal barrier alot more sufficent for piston coatings then oil retaining coatings since alot of pistons come with special grooves for that?

also from a builder stand point, i have seen vurtually no wear on either coated and non, i used to use piston coatings for a while, but seemed like the condition after compared to a non coated was exactly the same on the skirts and walls. i can vouch for at least 10k on the motors ive seen daily driving, but on the other hand thermal coatings on top was a noticable difference in exhaust temps, and cooler ect numbers across long driving

 

I wonder why OEM Type R pistons are coated and the rest of honda's pistons aren't?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by tony1 &raquo;</TD></TR><TR><TD CLASS="quote">I wonder why OEM Type R pistons are coated and the rest of honda's pistons aren't?</TD></TR></TABLE>

I called Mr. Honda today and asked him and he said it was a mistake and he wanted me to let everyone know he was very sorry for the mix up

 

The reason I specifically chose .0035 instead of the suggested .0025 was for heat induced by the turbo. Had this been a low boost applilcation I probably wouldn't have accounted by loosening up the tolerance.

Lets play devils advocate and say I chose to use .0025 because of the "anti-friction" coating and whatnot. I believe that even after doing this the chances of blowing a motor are much more risky using this approach because heat makes things expand. No amount of coating will account for this. Even though you may be able to run a more slack clearance, you still have to overcome the heat produced from the high amounts of boost. CP pistons call for .0035 but they don't have that "fake" coating like the wisecos. So if indeed the tolerances open up after break-in .001 like Tony said, that brings it to equal the CP's but now for my build I'm looking at .0045? Thats pretty slack and hopefully I won't loose too much oil... I hope wiseco doesn't suggest .0025 because of their stupid *** coating...

 

Coated pistons and clearances are fine if done the right way. Call the manufacturer of the coating being used and find out how the clearances should be set. It's not magic. If Wiseco says to set the clearances at .0025 over the coated piston o.d., then do it. The manufacturer will know how to set it up properly and will tell you. If they don't know, then you bought the wrong ****. lol Wiseco is who you should be talking to, not HT.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by ninesecrx &raquo;</TD></TR><TR><TD CLASS="quote">
I have used 1 set and sold 1 set of Calico coated bearings and we went with their suggestion of "tighter clearance" and I can say I will never use their coatings on bearings ever again.</TD></TR></TABLE>


What type of problem did you encounter by using coated bearings?

 

Honda is coating lots of their pistons now. I like to run the "R" pistons on oem builds because the pistons are cheaper and the coating is a nice bonus. I had t-bone coat another set of pistons I had and he burnished most of the visible layer off so that it would not create any confusion about clearances.