rr/3b: cam idle roller & water pump

[Phil Payne]

> 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.

THIS VIN BREAK IS NOT RELIABLE.

Sorry for shouting.  Known problem with victims all over the place -
Audi fitted approximately 50 'back-level' engines to MB ur-quattros.
This is the text of a letter I sent to the major UK parts suppliers on
26 November 2000:

Towards the end of the 1988 model year, starting at chassis
85-J-900644, Audi started fitting what I have long referred to as a
"Series 2" MB engine to the ur-quattro.  This was nothing more than
adoption of some hardware changes made in parallel to the donor MC
engine - a new tray-like design for the inlet manifold casting,
transfer of the wastegate frequency valve feed from unthrottled to
throttled air, and other minor changes.

The only parts change of note was the adoption of the 'Supertorque'
timing belt used some years before on the aluminium engine - part 074
109 119 instead of 034 109 119 - and related parts such as the idler
roller, cam gear, water pump and crank pulley.  According to Audi,
this change was effective from 85-J-900644, as above.

However - we have a number of cars on the club register with later
chassis numbers and earlier engines.  These cars use the 120-tooth
timing belt.  There are too many to be accounted for by later engine
swaps - we know many of them to be original factory shipments.  The
only conclusion can be that Audi fitted a batch of 'old' engines to
ur-quattros at the end of the 1988 model year.  Model year 1989 is not
affected.

To the extent of my knowledge, the chassis numbers affected within the
UK are:
85-J-900732, 85-J-900736, 85-J-900738, 85-J-900748, 85-J-900750,
85-J-900752, 85-J-900766, 85-J-900767, 85-J-900768, 85-J-900770,
85-J-900771, 85-J-900773, 85-J-900774, 85-J-900775, 85-J-900776,
85-J-900778, 85-J-900780

Other cars within this range may have either engine.  Externally, the
most definitive factor is the front of the inlet manifold - if the
tray-like lip is absent the engine is most likely 'Series 1' and
probably needs the 120-tooth timing belt.  If it is present, the
engine is most likely 'Series 2' and probably needs the 142-tooth
timing belt.  In my opinion, this is a more reliable indicator than
the chassis number.

--
  Phil Payne
  http://www.isham-research.com/quattro
  +44 7785 302 803
  +49 173 6242039