Ralphy ... possibly because they didn`t run the coatings/engine in . When Harold does them , it`s a 4 step process from degreasing/metal prep to preheat to application to curing in the ovens . When the engine is run for the first time , it takes a while for the coatings to burnish in ... and when done they are in the range of one or two tenths in thickness ... actually partially in the "pores" of the metal . The first time , you may see slightly elevated engine temps . Run it in , shut it down , change the
oil and go racing . Again , if it didn`t work , I don`t think Roush , DEI , Penske and the others would be using them ... and I`ve been in the shop when those teams dropped off and picked up parts . I also won`t dispute the magazine tests , but I`ve learned over the years to take a lot of that stuff with more than a few grains of salt .
One of the NASCAR teams made a setup to measure hp absorbed by the drivetrain before and after and they "found" about 15 hp after the coated tranny and rear end were run in . There is also another little trick they use that I can`t tell , but the coating allows this to be used ... and save hp .
One comment on the ceramic piston top coatings ... I was told that the main purpose was to keep carbon off the tops and act as a thermal barrier to keep heat in the combustion chamber .... also helps keep the
oil cool that splashes on the underside of the piston . In the old days , we polished the tops of the pistons like a mirror . Is it worth it on a street car ? No ... on a race car where every little thing adds up ... yes . The valve spring coating reduces spring temps and adds longevity . For a street car , I would do all bearings , valve springs and ring gear for added insurance/life .