Originally Posted by treecarp
Boy, Ford is very protective about specs for their parts, aren't they? Couldn't find dimensions/specs for Motorcraft belt ANYWHERE!! Guessed that correct belt must be 84.2", as the Motorcraft drive belt part number ended in 842. Then got a different brand from another auto parts store that was 84.2", not 83.5" (that was the Dayco belt's measurement). New belt installed perfectly, problem solved. Thanks for all the input, & hope this thread helps other Zetec owners replacing drive belts. By the way, the shop that worked on the car before me somehow managed to get the 83.5" belt on & my friend drove for 600 miles before the tensioner pulley gave up; I should have posted a pic of the horribly mangled thing!!
I also just pulled a 2120mm (~83.46 in) serpentine belt off my engine. Don't know how in Sam hell it got fit on there. Could barely read the part num but was a motorcraft belt too. I found this thread because I was also under the impression that JK6-842-A (for '01 SE DOHC w/ AC) was 84.2 in.