Re: 2.5/2.6l (was k24/26 hybrid aka RS2) - Crank, Rods &clearances??

[OorQue@aol.com]

> Can't this be done by just changing out the crank & rods?  i.e. go from the
>  86.4mm stroke crank to the 92.8mm?

This obviously depends upon which pistons you're starting with but I 
seriously doubt it.  If the deck height of the block stays the same, then the 
additional stroke has to be accomodated by either raising the pin height of 
the piston (which is the best approach) or running shorter rods (which is a 
highly questionable approach).  I suppose it's possible that if you 
absolutely had to reuse the original pistons for some reason, you could run a 
spacer between the block and head to artificially create some additional deck 
height but IMHO, this would fall into the questionable category as well.
   
>  Is the ANN bock bore "deep" enough to accommodate the additional 6.4mm
>  piston travel at the bottom of the stroke?  Is the oil pan deep enough?

I have no idea as I've never looked inside an "ANN" block ... as for the 
increased piston travel, it's only half of whatever additional stroke you're 
using since the piston travels upward as well as downward.  ;^)

>  Is there enough clearance on the stock piston skirts if the rods are
>  shortened by 6.4mm?

Shorten the rods?  You mean like cut and reweld them or what?  Based upon the 
nature of your questions, I'm starting to think this project may be a bit a 
teeny-weeny bit over your head ... no offense intended, just a warning that 
this may not be the best engine-based project to hone your skills upon. 
  
>  I found part of an old thread in the AudiFans archives mentioning an
>  Oetinger 2.5 liter conversion that Oetinger did in Germany for the 4000Q 
for
>  @ $5,000.  Does anyone have any experience with that conversion or any of
>  the requisite part(s) information?

Here in the US, Eurospec put together a crank-and-pistons kit for the 20v 
non-turbo motors that ran about $2k (I don't know if they ever got around to 
doing one for the 10v motors or not) and there are several tuners in the UK 
(Tim Styles Racing, et al.) that offer assembled 2.5L / 2.6L non-turbo short 
and longblocks in that price range.  German tuners are more willing to build 
turbo versions of this motor but their prices are higher still.  Don't forget 
that the motor itself is but one part of the project, since you'll also have 
to adjust/modify/replace parts of the FI and exhaust systems to deal with all 
of the additonal air that's being pumped around.

JG