20v heads on MC blocks

[Ken Keith]

OK, I'll put my ideas out there, since I am not in a position to act on them.  Not to mention act on much of anything for a while now that I've acted on some of my ideas! :-P

In the Audifans marketplace SJM posted for someone else, a '91 200q20vt with a hole in the side of the block.  It's listed for $2k obo, you tow/pickup.

This got me thinking two things.

One, was that the hole in the block might be attributed to use of the improper ignition rotor (the correct one has a much thinner blade), which can cause the wrong cylinder to fire.  This may be related to running high boost levels.  Some thoughts that jump to my mind is the dynamics of a wasted spark system.  Basically there can only be one spark, and once it's gone it's gone.  But the system "sends" the spark to the cylinder that is under compression rather than empty/exhausting/ed.  This may have to do with the ionization point or something, I'm pulling technical terms out of the air here.  I don't know what I'm talking about, but I can imagine a scenario where the intended cylinder is so packed with boosted fuel mixture, that the spark would "prefer" to jump the ignition rotor/cap gap to a different cylinder.  This  is what I imagine happening in my mind, but I have no knowledge of the laws of physics happening here.

When I see the Eurocar Service webpage, which shows some nasty bent stock connecting rods, offering some stronger aftermarket ones, it makes me think the same thing probably happened there.  That website blames it on running 24psi of boost, and I don't know any different.  But it would seem that firing the wrong cylinder, a symptom of the wrong rotor (and maybe of just running that level of boost at all with a physical ignition distributor, after all Audi switched the next year to electronic) would cause the rod to bend that way.

The other thing, which is where my question came from, was to get that '91 200q and replace the block with an inexpensive MC-based one.  If the block doesn't have to be a 3b one, then that car could be back on the road without too much cost.  Figure it's worth in the ballpark of $6.5-7k, less the $2k price, gives you some room there to get it going.

It was just a thought.  I have to tend to the irons I put in the fire, and the other fires with other irons in them also.

Later,

Ken