Alternator change, pulley smaller on new unit.

slinky said:

In the process of changing my alternator for a new one off ebay and I only noticed the pulley on the new unit is smaller than the one being replaced.

Can I use it with the smaller pulley or do I need to change it.
I think I will need to change it from what I've been reading but thought I should make sure.

Thanks
Aaron

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sierrafery said:

I suppose that's a V8 then.....(coz the Td5's alternator goes together with the vacuum pump)

Read the caracteristics on the two alternators, V/rpm ...etc, if they are the same just swap the puleys........if they are different u have o try to fit it with the belt tensioner coz using a bigger pulley on the new one it might not generate enough voltage.
.

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slinky said:

No its a 300tdi, I meant to put that in original post.

Just tried fitting it as is and the belt is no where near tight.

The advert for the alternator does say "Please note you may need to fit the pulley from the old alternator"

I guess I hoped it would have the right one.

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sierrafery said:

be glad u didnt succeed to fit it then........ smaller pulley = bigger voltage.....could have f***ed up the whole charging system

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paul_c said:

Not quite true, its an alternator (with regulator) and it copes with different engine speeds fine, so it would have coped with a slightly different size pulley no worries.

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