Renny II Mazda ROTOR Surface Coating..
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Joined: Jan 2013
Posts: 356
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From: Ohio
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.
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.
Rotary Evolution
Joined: Oct 2011
Posts: 853
Likes: 2
From: Central FL
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.
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.
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.
rev it up
Joined: Feb 2004
Posts: 1,590
Likes: 11
From: Brisbane Australia
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.
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Joined: Jan 2013
Posts: 356
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From: Ohio
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.
