Alternator v-belt tensioning question.

[quk@isham-research.demon.co.uk (Phil Payne)]

In message <Pine.GSO.3.96.980130111715.3792C-100000@expert.cc.purdue.edu> Albert Ng writes:

> ...  87 5kcst

> So, what is the best way to accurately measure the v-belt tension? Haynes
> says "deflect the belt under moderate thumb pressure by 10 to 15mm". What
> is supposed to be "moderate thumb pressure"? Any suggestion will be
> greatly appreciate.   

I only have the values for the WR and MB engines, although the MB should be
fairly close to the MC - can anyone confirm the following?
 
There are _two_ definitions in the microfiche.
 
a) Torque on the adjuster nut.  This will be difficult to measure without
   a suitable Crowfoot socket, because the fixing bolt is concentric with 
   the adjuster.  Nevertheless the values are:
 
   Old belt - 4 Nm 
   New belt - 8 Nm.
 
   (Obviously to avoid 'multiplier' errors, the torque wrench should be
    inserted at 90 degrees to the Crowfoot socket.  These are, BTW, tiny
    torque values.)

b) Thumb pressure.  Again, we need the German mechanic's calibrated digits,
   as we did recently for the hydraulic pump's '90 degrees between thumb
   and forefinger'.  Nevertheless:
 
   Old belt - 5mm
   New belt - 2mm.
 
I find '10 to 15mm' a bit excessive.

-- 
 Phil Payne
 Committee Member, UK Audi [ur-]quattro Owners Club