Re: Compression decreasing block on MC turbo engines...

[DeWitt Harrison <de@aztek-eng.com>]

At 08:57 AM 11/14/97 +0200, "je'rard" wrote:

>> The later MCs changed CR to from 7.8 to 8.4.  I'm sure this is just
>> a piston swap. In principle, you should be able to get to 9.3. This
>> wouldn't get you 20 V, cross flow or dual knock sensors though.
>
>What year did they change the CR of the MC?

In the US, the 5000tq badging reverted to the standard 200 in
model year 1989.  The MC engine was carried over into the 200 but
with the increased compression ratio.  The 3B engine was adopted in 1991.

>I suppose if I did hunt down S4 pistons (which seem to be in abundance
>at the Audi/Porsche stripping works in Johannesburg (??!!??)) I would
>need to gain more air flow by fitting the 20V head as well, right?
>Say, if I coughed up the dough and bought the S4 pistons, would they fit?

Dunno offhand.

>Isn't the S4 a 2.5 litre motor? I spoke to someone at the stripping
>works and he said the job would need new con-rods and crank as well.
>True? As for dual knock sensors, I have them already.

It would be cheaper and far more effective to swap out the whole bloodly
thing at once. Wiring harness too.

DeWitt Harrison    de@aztek-eng.com
Boulder, CO
88 5kcstq