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Has any of you had experience with dry film lubricants and thermal coatings in your builds? I've seen the various applications from piston crowns, skirts, rods, blocks, manifolds, bearings, brake rotors etc etc but have not seen a lot of public information about people using them. Don't know if it's maybe just people trying to keep their "recipes" a secret or if they aren't worth the effort/cost.
A long time ago I ran skirt and crown coated pistons on my 4a-ge. These were replaced by uncoated versions. No measurable difference in power or torque.
The pistons for my VQ30 are also skirt and crown coated. The engine was dynamically balanced (so bottom end assembled and spun round in the block whilst fixed to a table that had hideously accurate sensors on it). Most of the coating on the contact point on the thrust face of the piston was already worn away by the time they finished.
Didn't cost much so did it anyway, wouldn't be too concerned about it though. In my case the skirt coating mostly seems to have just protected the pistons during balancing.
I have had the bearings supplied coated, can't comment on any improvement, mostly had it done because it didn't cost much extra and my clearance are on the loose side of loose and I want a bit of extra protection during the first ever start up and running of a brand new everything never build anything like this before build (rather than rebuild of a known spec engine).
Exhaust manifolds. Do it. Makes a measurable difference to engine bay temperature (and skin burns when you accidentally touch it!). Might make a difference to exhaust gas speed and hence power but not the primary reason for doing it. You can use exhaust wrap, but it doesn't tend to last long before looking a mess and starting to fall apart, a coating is cheaper in the long run.
Yeah, the theory behind thermal coatings for combustion chambers, valve heads and piston crowns to prevent heat transfer to engine componers makes sense. The dry film lubricant more for increasing durability than horsepower.
I've seen some other "heat dispersant" products that should help parts to dissipate heat faster like brake calipers, rads, intercoolers, compressor housings etc. but then again, haven't seen many numbers on them. Only seen the coatings advertised with parts that are being sold with them already applied on like intake manifolds, carbs, etc.
Thanks for the input btw!