Date: Mon, 2 Nov 1998 19:02:06 +0000
From: Nicola Burgess
Subject: [imps] Alloy Pulleys
I am currently rebuilding a 930cc engine, (Imp Sport cam, head, carbs) what I want to know is do I really need a set of these alloy pulleys I heard about, what are the benefits. I've priced them up with a few suppliers and they are very expensive.
I could get some made by a friend who make those sorts of things, but aren't they different sizes to the standard ones.
--
Nicola Burgess
From: Paul Williams
Date: Mon, 2 Nov 1998 19:33:37 -0000
Subject: [imps] Re: Alloy Pulleys
>do I really need a set of these alloy pulleys I heard about, what are the benefits
The main benefit is to stop the fanbelt mangling itself up and flying off at high engine revs.
>aren't they different sizes to the standard ones.
Their outside diameters are bigger to provide a deeper groove for the fanbelt to run in, although if you're running an alternator as opposed to a dynamo the effective diameter of the alternator pulley could be a bit bigger as it will produce a satisfactory current at lower revs than a dynamo.
Paul
From: Mark Norman
Date: Tue, 3 Nov 1998 10:12:01 -0000
Subject: [imps] Re: Alloy Pulleys
>fanbelt to run in, although if you're running an alternator as opposed to a >dynamo the effective diameter of the alternator pulley could be a bit bigger >as it will produce a satisfactory current at lower revs than a dynamo.
When I bought my alternator & pulley for it from my local expert they told me that the alternator would need a smaller pulley - alternators need to run faster than dynamos to produce the extra current, however they are more efficient, so they don't produce so much drag on the engine despite their smaller pulley & higher speed. They will produce a satisfactory current at lower revs, but those revs are engine revs, not generator revs. Perhaps it depends on the type of alternator you fit.
Mark