byebyeL98

What is the best way to measure for the length of the serpentine belt i'll need? How should i position the tensioner while doing this? Any tips would be greatly appreciated! thanks!

Perfusion

Have you done aftermarket stuff (UD pullies, etc.) that would change your belt to something other than OEM? If not, I just would suggest calling Autozone (or the like) and ask for a Goodyear Gatorback or Gates belt to fit your year car...

byebyeL98

i had the March underdrive pulleys on the alternator and the crank. when i replaced the alternator, i left the stock pulley on it (didn't want to underdrive it too much), but kept the March pulley on the crank. now i need to find a belt to fit...

thanks

JCAIRE2

IS the pully you bought for the alternator smaller or larger than the stock one? If it's smaller, it's an overdrive pully and should be used to avoid low output.

byebyeL98

good point! i didn't even think of that. the stock size pulley is on the alternator now, which combined with the March crank pulley would actually LOWER the output, right? so i'd be better off just using the stock crank pulley and going with a stock serpentine belt, right?

Bob86ZZ4

I removed my ac compressor so I needed to come up with the right size belt. I cut the original belt. Then wrapped it around the pulleys the way I wanted it to run. Then I overlapped it and pulled it tight as I could and used a sharpie marker to draw a line where they overlapped. Then I took that to the Autozone and put it on their measuring thingy and told him to give me a belt 1/4" shorter than that. It's worked like a charm for many thousands of miles.

byebyeL98

excellent idea - thanks!

glad i got this pulley stuff sorted out!!!

JCAIRE2

I would put the underdrive crank pully on and the overdrive alternator pully on. That should even it out. But if you don't want to change the pully on the alternator, then the stock crank pully would be best. Clear as mud?

byebyeL98

absolutely

for now, i'll keep the smaller crank pulley (which is the March underdrive pulley) AND i'll keep the stock alternator pulley (which is also smaller, giving me a few more revolutions per belt length). if that still isn't enough to put the electrical system where it needs to be, i'll switch back to the stock (larger) crank pulley.

now i just need to measure it all up and get a belt!!!

thanks to everyone for their input!!

pablocruise

I *think* the belt length (expressed in inches) is what makes the belt's actual part number. That and the amount of ribs on it. Example: the belt is 56" long and has 6 ribs....so maybe some combo of letters and a "56" and a "6". ????????
Wrap a measuring tape around the belt routing.

93Quasar

I took a piece of twine and wrapped it around all the pulleys. I put a mark on the twine with the tensioner fully relaxed, and another mark with the tensioner fully tight (IE, mark at both extremes of tensioner movement). Then I measured the length to the marks and shoot for something between them. If you can't get exactly in the middle, I would error for a belt slightly shorter than longer - they can stretch some when tensioned.