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Renny II Mazda ROTOR Surface Coating..

Old 05-15-2013, 10:01 AM
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Has any more been learned about this coating?

Molybdenum disulfide seems like a good guess to me as to what it is and why it's there. I know from my work in the nanoparticle field that various oil companies and other companies are currently investigating other disulfides in nanoparticle form (most notably tungsten disulfide and titanium disulfide) as additives for friction reduction.
Old 05-15-2013, 10:11 AM
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Originally Posted by fyrstormer
I doubt much heat leaks out through the rotor bearings' lubrication jackets. The rotor faces are constantly being cooled by fresh air from the intake, just like pistons in a piston engine do. The first rotary engines actually used oil-resistant rubber for the round seals around the bearings, because they stayed cool enough that the rubber wouldn't melt.

As far as I know, the single largest reason why rotaries leak so much heat is because one section of the rotary chamber is constantly exposed to combustion, and the heat absorbed by that section of housing never gets re-absorbed by fresh cool air like what happens to the cylinder head in a piston engine. So, to keep that part of the rotary housing from overheating and warping, there has to be massive watercooling in that area, and THAT is where most of the heat escapes, causing the efficiency drop rotary engines are known for.
he never mentioned the bearings being the heat sink. the heat sink is the oil sloshing around inside the rotor against the oil faces.
Old 05-15-2013, 04:56 PM
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Shame we cannot buy the upgraged rotors for S1 rebuilds.

I wonder it such coatings can be applied to the rotor face. Do you think this will increase EGT
Old 05-16-2013, 01:30 PM
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My new rebuild has ceramic thermal barrier on the rotor face and a moly based DFL on the rotor sides, seal groves, and seals. If I can ever get it running right I'll keep everyone posted on the longevity.
Old 05-16-2013, 05:12 PM
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I had a couple of layers of ceremic coating applied to the inside and outside of my aftermarket headder. I noticed some very minor flakeing after 2 years of use. So I would not trust ceremaic coating to internal components.
Old 05-17-2013, 01:01 PM
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Originally Posted by Spin9k
To save the CAT. Otherwise EGT would be pushing 2000 def F easily, way beyond CAT spec limits.

Even with our rich tune our EGT's are high.

IIRC 1730 degrees F is considered the temperature at which the catalyst will start to degrade. On an average cruise at 70 mph, I see average catalyst temperatures around 1600 degrees F. Up to 80 or 85 mph (in 6th gear) and it's easy to get it past 1750 degrees F. When going flat out I've seen over 1850 degrees F.
Old 02-08-2017, 02:03 AM
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Sorry for dragging up an old thread.

Are there any updates on this? Quite clearly the rotor has a coating in the image.
Old 02-08-2017, 10:20 AM
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Update on what?
Old 02-08-2017, 11:29 AM
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Originally Posted by 9krpmrx8
Update on what?
Confirmation the SII engines have coated rotors.
Old 02-08-2017, 11:55 AM
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If Mazda says they do, then they do. Whether it does anything beneficial is hard to determine.
Old 02-08-2017, 12:33 PM
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Is there anything official to confirm they do use this coating?
Old 02-08-2017, 01:11 PM
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See the picture in the first post.
Old 02-08-2017, 01:14 PM
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Originally Posted by 9krpmrx8
See the picture in the first post.
Anything describing this from Mazda? The image isn't clear.
Old 02-08-2017, 01:31 PM
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Nope, Ash8 would be the only one who could find that. But when we tear apart this 2009 engine with only 9000 miles on it I'll post pics.
Old 02-08-2017, 01:38 PM
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Originally Posted by 9krpmrx8
Nope, Ash8 would be the only one who could find that. But when we tear apart this 2009 engine with only 9000 miles on it I'll post pics.
That would be perfect!
Old 04-26-2017, 01:59 PM
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more important question is does the coating keep the carbon deposits in check...
Old 06-12-2017, 09:22 PM
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I hope my reman has these same rotors...
Old 06-15-2017, 03:06 PM
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Originally Posted by ne0tas
I hope my reman has these same rotors...
got my reman from mazda in, looks like series 2 remans still have the special rotors

Last edited by ne0tas; 06-15-2017 at 05:53 PM.
Old 06-15-2017, 03:11 PM
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A lot of good that special coating did,
Old 06-15-2017, 04:33 PM
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Did the carbon form those lines or is that the coating?

Either way, until I see a picture of an S2 rotor fresh out of the engine, I'll call that coating snake oil.
Old 06-15-2017, 08:20 PM
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Is there a pic I'm not seeing?
Old 06-15-2017, 11:44 PM
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Yes, it's gone.
Old 06-30-2017, 02:49 PM
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The coating looks like DLC to me.
Old 06-30-2017, 05:58 PM
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Originally Posted by 9krpmrx8
Yes, it's gone.
Any chance you could re-upload?
Old 06-30-2017, 08:11 PM
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TX

Originally Posted by IamFodi
Any chance you could re-upload?

Neotas posted it, I didn't.

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