[s-cars] CPS mounting boss changes in early 92 - 93 AANs

Thu Jul 31 09:12:14 PDT 2008

The 3B was used in the early S2 coupes and the 1991 200 20vt.  The ABY (like our AAN) was used in
 the later (93 -96) S2 coupes.  The RS2 ADU was used in the RS2 from 94 to 96.  All three engines
 have the reverse intake manifold (IM) (to our AAN IM), i.e. the throttle body is at the firewall end of
 the engine.  Indeed the RS2 IM, has "PORSCHE" cast into it and would have been an easy bolt on
 swap on a 3B.  

Now the question is whether Rune's CPS bolt on boss will work on a 3B head as well as a 7A head (my
 guess is yes but you need to contact Rune to ask him).

Oh, yeah, I guess that the engine the head came from had a timing belt failure (??).  Not that that is a big
deal if the head is already off.  You wanted to do the valve guides and seals anyway, right? ;>)

Good luck.  

Dave F.

----- Original Message -----
From: Ben Swann <benswann at verizon.net>
Date: Thursday, July 31, 2008 9:01 am
Subject: RE: CPS mounting boss changes in early 92 - 93 AANs
To: 'Ben Swann' <benswann at verizon.net>, 'David Forgie' <forgied at shaw.ca>
Cc: "'Akiska, Erol'" <eakiska at uncc.edu>, s-car-list at audifans.com

> I did look at this again.  The casting numbers on both AAN 
> and head in question are
> 034-103-373.  I also found 3B 007696 behind the Exhaust 
> manifold and no similar marking
> on the AAN head.  Also it does appear that the valve cover 
> may be the same as a 3B.  So
> it is probably a 3B that was being/had been canverted to use 
> some of the RS2 stuff.
> Other than that, it looks the same as the AAN head.
>  
> That's all.
>  
> Ben
> 
>   _____  
> 
> From: Ben Swann [mailto:benswann at verizon.net] 
> Sent: Thursday, July 31, 2008 11:48 AM
> To: 'David Forgie'
> Cc: 'Akiska, Erol'; 's-car-list at audifans.com'
> Subject: RE: CPS mounting boss changes in early 92 - 93 AANs
> 
> 
> Dave,
>  
> Perhaps it is not any sort of RS2 head, but I really bought the 
> head for the RS2 water
> jacket and intake manifold attached to it - those are definately 
> RS2 - at least the
> Intake which has PORSCHE on it, and the water manifold which is 
> same as 3B/RS2.  The
> head numbers are the same as AAN.  I do think this head is 
> an "in between" version since
> I have no other explanation for the blocking plate.  I 
> suspect some sort of coil bank
> was used, since this does not have the same valve cover as the 
> AAN - it is not the same
> as the 3B either.
>  
> I'll send picutures when I get a chance.  The head needs to 
> be rebuilt since a few
> valves are bent.
>  
> Mainly I just need to find out about the CPS boss and I'll 
> contact Rune.
>  
> Thanks,
>  
> Ben
> 
>   _____  
> 
> From: David Forgie [mailto:forgied at shaw.ca] 
> Sent: Thursday, July 31, 2008 11:20 AM
> To: Ben Swann
> Cc: 'Ben Swann'; 'Akiska, Erol'; s-car-list at audifans.com
> Subject: Re: CPS mounting boss changes in early 92 - 93 AANs
> 
> 
> Er, ah, Ben, I think you may have been "had". The RS2 engine, 
> the ADU, is an evolution
> of the UrS4
>  AAN and S2 ABY.  The RS2s were first built in March 
> 1994 and were well past that AAN
> early 
> build date transition from 3B (distributor, single coil) to the 
> AAN with the CPS behind
> the cam 
> sprocket.  The current PN for the AAN head is 034 103 351N, 
> the same as the RS2 head.
>  
> Sounds more like you have a 3B or 7A head with the distributor 
> hole blanking plate
> installed.
>  
> Photos and any PNs in the casting would be interesting to see.
>  
> The contact for the fellow with the CPS boss for a 7A head is
>  
> Rune at:  runeparts att hotmail  dotty com
>  
> Dave F.
> 
> ----- Original Message -----
> From: Ben Swann <benswann at verizon.net>
> Date: Thursday, July 31, 2008 7:47 am
> Subject: CPS mounting boss changes in early 92 - 93 AANs
> To: forgied at shaw.ca
> Cc: 'Ben Swann' <benswann at verizon.net>, "'Akiska, Erol'" 
> <eakiska at uncc.edu>,s-car-list at audifans.com
> 
> > 
> > Dave,
> > 
> > I can't answer your question, but do happen to have a version 
> of 
> > the head you describe.
> > This supposedly RS2 head differs from the AAN head in that 
> there 
> > is no mounting boss for
> > the Cam Position Sensor as on the AAN head.  I have both 
> > side by side.  The distributor
> > port is blocked off with a circular cutout, but I don't see 
> how 
> > either distributor or
> > front mounted hall would have been used. I think this Ear;u 
> RS2" 
> > head is the same or
> > similar as the one you have shown with the CPS boss - where do 
> I 
> > get one of these?  I
> > see you mention it below - contact info?
> > 
> > I don't know if I can even use a distributor with the RS2 
> intake 
> > manifold or not -
> > haven't tried.  Tuna can?  Is that like an 
> abbriviated 
> > distributor with hall pickup only
> > in it?  More info. please as I am looking for 
> alternatives 
> > for this head.
> > 
> > Ben
> > 
> > [Date: Wed, 30 Jul 2008 11:07:59 -0700
> > From: David Forgie <forgied at shaw.ca>
> > Subject: [s-cars] CPS mounting boss changes in early 92 - 93 AANs
> > To: s-car-list <s-car-list at audifans.com>
> > Message-ID: <cfb6d7695b2e3.48904b8f at shaw.ca>
> > Content-Type: text/plain; charset=iso-8859-1
> > 
> > As you know, the cam position sensor (Hall sender) on the AAN 
> > engine is typically
> > mounted on the head, behind the exhaust cam sprocket.? 
> > Exceptions are the very early
> > AAN's that used a vestigial (tuna can) "distributor" at the 
> back 
> > side (intake side of
> > the engine), driven off a gear on end of the intake cam. That 
> > was a carry-over from the
> > 7A and 3B engines (which had full distributors).
> > 
> > Up until yesterday, I always thought that when the CPS moved 
> > from the tuna can, to
> > behind the cam sprocket, the mounting boss was cast into the 
> > head.? NOT so.? There is
> > evidence (as shown in the link below) that the factory used up 
> > some 3B heads by
> > supplying a separate mounting boss that was bolted to the head 
> > (and then the CPS was
> > bolted to it).? I am curious as to when this practise started 
> > and stopped, based on
> > build date.? So if you have such a non-cast boss, can you 
> please 
> > post your car's build
> > date?? (Thanks).
> > 
> > Photo of the add-on CPS boss (note - no PN in the FA for this):
> > 
> > http://forums.audiworld.com/s4s6/msgs/231574.phtml
> > 
> > Here is a photo of the "normal" cast CPS-mounting boss:
> > 
> > http://forums.audiworld.com/s4s6/msgs/231588.phtml
> > 
> > This all came up because a fellow in Norway has developed an 
> add-
> > on boss that will
> > permit 7A heads to be used with normal AAN CPSs.
> > 
> > Dave F. ]
> > 
> 