rr/3b: cam idle roller & water pump

[Dave Eaton]

i'm changing the idle roller and water pump of the ur-q.

the idle roller, which is used for the 10v (up to late mb, "j-900 643),
*and* the 'rr' is 74mm wide is part number 069 109 243b.  interestingly
there was a change for the late mb (june '88) engines to a 68.7mm wide
roller, but the rr reverted to the 74mm unit.

anyway, 069 109 243b is an "skf" bearing.  however, if you go to skf as i
did with the number stamped on the body of the bearing (395 955), you will
be told that that is obsolete.  this is due to a problem with skf's records,
and the fact that skf are producing an amended unit.  anyway, the bearing
number for the new skf roller is "f-220096".  the only change is that the
method of holding the 2 halves of the roller has been changed.  usual story,
price from skf (ex stock) was less than 50% of the price from audi.

there also appears to have been a running change on water pumps.  the new
units (both for the adu and the rr) have plastic impellers, while the
original units use steel.  apart from the obvious weight savings (quite
significant, probably 1kg), the other advantage is that you get to return
the new unit to audi because the plastic impellers have been broken in
transit as they have been banging around in the box, without any packaging
to protect them.  i returned 2 units over the counter, before they found one
which was ok.

dave
'95 rs2
'90 ur-q