RE: E36 Overrev (or maybe not?)

["Snyder, Daniel" <Daniel_Snyder@xxxxxxxxxxxx>]

In reading Duane's post, I was led to think about another M3 I know (not
mine).  This car exhibited classic signs of an overrev, with the trouble
starting after a track weekend.  This included greater engine noises, power
loss, etc.  Leakdown/compression tests showed evidence of something wrong in
two cylinders.  The car was still driveable, just seemed weak.

Well, after taking off the head (after long debate as to the cost of repair
versus a rebuilt engine), all of the valves were perfect!  So, what was
wrong?  Upon further inspection (@ Midwest Motorsport in Chicago), it was
revealed that many of the rings were in various states of freeze (in the
pistons), and the cylinders had turned from circles to ovals!  Ouch!

The damage was typical of an overheated block.  Okay, we all know M3s run
hot at the track, and this LTW has seen its fair share of hard driving.
BUT, this car had never seen the water temperature go above normal ranges.  

Ahh, you say, "but what about oil temperature"?  Well, this car ALSO has a
Euro oil cooler, the higher capacity GT oil pan (this is a LTW after all),
AND the higher capacity Euro radiator!  None the less, the oil temperature
did run high at the track (about 295 in the pan), and this is believed to be
the cause of the overheating, as everything in the oiling system appeared
normal.

Anyway, the point is that US M3s run hot, and long term exposure may lead to
symptoms that are similar to an overrev.  I don't know if this is a
potential problem for other cars, or just a flawed motor.  Who knows?

As a side note, a Euro M3-motored car that I know of (with the same Euro
cooling system and GT oil pan) runs an oil temp at the track of only 180-200
degrees.  Of course, the Euro 3.2 also has a lower thermostat than other
BMWs.

Dan Snyder
'74 2002tii
'92 325is ITS racecar
'95 M3 LTW

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