For a time I used STP as an assembly lube, until the engines I put together with it started having bearing-related failures. Just to convince myself the problem couldn't possibly be the STP, I put one more engine together that way. You guessed it- - - - -problems with that one, too! Gummed-up oil pump relief valves and subsequent oil pressure loss and bearing noise or worse seemed to be the most common problem.
On a similar note, a series of dyno tests we ran with Slick 50 recorded a documented 5% power LOSS after using the additive according to directions. Those results were corrected for temperature, barometric pressure, and humidity, BTW.
Jerry
