FAO gary and MattJ - SBD underdrive multi-vee pulley gen gen gen
thought i would put this up in the forum so its searchable in the future.
anyone else tuning in, this is regarding running an early 20XE with late C20XE mult-vee pulleys (SBD's under-drive alloy multi-vee crank pulley actually), but using a half length belt only servicing the altenator. (as opposed to a long belt driving the altenator and pas pump)
i took a loop of electrical wire down to halfords, which i laid round the pulleys to made up a pattern for a belt. found one that was slightly bigger than my template, but i made the template with the altenator as close to the engine as pos. anyway, its a perfect fit and is meant for E36 3 series BMW airconditioning (1991 - 1997ish). they seem to have 3 belts, alt, pas and aircon, and from the listings it appears to be only 316i and 318i applications that use this particular aircon belt.
the crank pulley went straight on, but the altenator pulley swap was not quite so straight forward. it stuck out too far and was hardly any thread to get the nut onto. so, theres a shim between the shaft and the fan/pulley, had to chop this in half, and then because the fan was closer to the ALT body, had to trim the blades too.