Thread: Running a 'B' section belt on an 'A' pulley.

Originally Posted by circlework

Hi All,

Just changed my Stage 1's 4BD1 alternator (40A) to one similar to a Hitachi LR170-401.
I'd like to know what the procedure is with the standard 'B' section fan belt.
i.e.: can I get away with running it on the new alternator's 'A' section pulley if the allignment is correct, or do people with these swaps either machine the 'A' section into a 'B' width, or change the pulley with another?
If the latter, what's it's part number?
Any answer / view would be greatly appreciated.

Thanks,
Daryl.

any chance of a photo of the 2 different pulleys?

I'd hit up a local auto elc to rat through their dead stuff to find the right section pulley. A B section is fatter by memory so will not sit into the groove as far and would be more prone to come out.

A-B belts are imperial sizes.not allways the same size.
they also can be made slight round so they can fit in pulley.

assume that an A is 13mm--1/2 measured at the top.
some are 11mm-7/16.

assume that a B is 15mm to 17MM

being a isuzu they are metric puley-15 A--so its more confusing.

http://v-belt.com.cn/Power_transmission_belt.html
pulley are giving in inches-belts are given in metric.

Originally Posted by circlework

Hi All,

Just changed my Stage 1's 4BD1 alternator (40A) to one similar to a Hitachi LR170-401.
I'd like to know what the procedure is with the standard 'B' section fan belt.
i.e.: can I get away with running it on the new alternator's 'A' section pulley if the allignment is correct, or do people with these swaps either machine the 'A' section into a 'B' width, or change the pulley with another?
If the latter, what's it's part number?
Any answer / view would be greatly appreciated.

Thanks,
Daryl.

G'day Daryl,
Changing pulleys to a genuine B section one depends on whether the new replacement alternator has the same diameter shaft and offset as the original Hitachi LR170-401. The part number for the original one is 8944103980 which includes the pulley and fan and I am guessing you would need to part with a limb or two to purchase a genuine one. Apparently they come as a pair according to the Army Perentie RPS. I do have a spare pulley but I am a long way from you. If you can measure the shaft I can check the pulley tomorrow.

Originally Posted by Bearman

*snip* I do have a spare pulley but I am a long way from you. If you can measure the shaft I can check the pulley tomorrow.

Thanks for your generous offer Bearman, but I'll take a raincheck for now.
I fitted the alternator up and it appears (see pic) that it is above the pulley by about 3mm.
I reckon it will stay where it's put.
Now, if it was an 'A' section belt, a Bosch rubber band or I was a slacker that never checks belt tension, then I'd be worried.

Thanks to everyone for your input and I'll repost if it goes belly-up.

Cheers,
Daryl.

Hi Daryl,
I don't think I would run the belt like that,I would change the pulley.
Just my opinion,its up to you.
Regard Jim.

replace belt bi if it looks crook.make a pulley.

you can see from the mark on the old pulley that they only contact on a small area.

I had a problem with a nissan it stipped in wet weather.i was using 1 belt instead of 2.
the work NPR has dealer air.
one of the the original fan-alt belt are used and a badly designed compressor belt just touching past the alternator and not used on the fan..takes a few weeks before it squeals on start up and the belts last 2-3 services.