tension on belt
tension on belt
Hey guys I've noticed my alternator belt has been losing tension every few days, I read the thread with the dude that couldn't get tension on his belt so he ended having to order new adjuster bars. The teeth on my adjuster bar look fine, what do you guys think it could be? Thanks.
Re: tension on belt
How old is the belt. New ones aren't terribly expensive.
Re: tension on belt
Not everyone agrees, but my experience with the adjustment nut/notched bracket is that they're closer to art than anything else, meaning are you sure you're really getting it tight?
On the other hand, many parts stores, on and offline, spec the alt belt at a 13X1060, sometimes 13X1055, when 13X1040, for most, but not all, seems to be the correct belt. So if you've got a 1060 belt it might never be getting tight and might be wearing. Are you maxed out on adjustment?
On the other hand, many parts stores, on and offline, spec the alt belt at a 13X1060, sometimes 13X1055, when 13X1040, for most, but not all, seems to be the correct belt. So if you've got a 1060 belt it might never be getting tight and might be wearing. Are you maxed out on adjustment?
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Technician117
- Posts: 11
- Joined: Jul 07, 2024 8:45 AM
- Location: Buffalo
Re: tension on belt
This is good info, re: belt lengths. I just picked up my first E28 (from this site, actually) and have purchased a set of belts to do as PM. Technically I bought two sets of belts as I needed some quickly to have in the car for the 1,200 mile drive home before the OE belts could make it to my house from FCP. I'll now be checking the length of each!Mike W. wrote: Aug 22, 2024 1:41 AM Not everyone agrees, but my experience with the adjustment nut/notched bracket is that they're closer to art than anything else, meaning are you sure you're really getting it tight?
On the other hand, many parts stores, on and offline, spec the alt belt at a 13X1060, sometimes 13X1055, when 13X1040, for most, but not all, seems to be the correct belt. So if you've got a 1060 belt it might never be getting tight and might be wearing. Are you maxed out on adjustment?
Re: tension on belt
not quite BMW but when I was having problems with the alternator belt seeming to lose tension on my Continental it was mostly a belt wear issue. First belt on the car after I got it lasted about 500 miles with several re-tensions before it hit max on the adjustment. Mix of causes, the alternator pulley was rusty and worn being a big one. Instead of a V groove it was more of a U so it only grabbed at the top edge which rapidly ate the belt away. The water pump pulley was bent from some clown using "water pump pliers" on it so the groove wasn't a consistent width all the way around. The fan clutch was also locked up so there was extra drag on the system. Fixing each of those significantly extended the life, I think the current belt has lasted almost 2 oil changes (~8k miles) now.
final bit of the puzzle is incorrect belt listings. Aftermarket belt catalogs show it as a 1/2" belt, the official Ford parts catalog lists it as a 3/8 belt. I think both are slightly wrong, the crank and water pump are BMW so probably 10mm, and the alternator pulley is 60s Ford. I think thats actually 1/2" but it might be 3/8". Looks wide to be 3/8" though, and I also don't know if the angle of the V is the same angle for metric vs SAE belts.
on other things I've had wear from improperly aligned pullies for assorted reasons. Bad tensioner bearings, worn/missing mounting hardware, bent brackets, etc. If the pullies are not in-line or if one is running at an angle relative to the others it will chew belts up.
final bit of the puzzle is incorrect belt listings. Aftermarket belt catalogs show it as a 1/2" belt, the official Ford parts catalog lists it as a 3/8 belt. I think both are slightly wrong, the crank and water pump are BMW so probably 10mm, and the alternator pulley is 60s Ford. I think thats actually 1/2" but it might be 3/8". Looks wide to be 3/8" though, and I also don't know if the angle of the V is the same angle for metric vs SAE belts.
on other things I've had wear from improperly aligned pullies for assorted reasons. Bad tensioner bearings, worn/missing mounting hardware, bent brackets, etc. If the pullies are not in-line or if one is running at an angle relative to the others it will chew belts up.