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RE: AutoX School - great, great, great!!!

To: "Kevin Stevens" <autox@pursued-with.net>,
Subject: RE: AutoX School - great, great, great!!!
From: "Carl Merritt" <cmerritt@luminous.com>
Date: Sun, 12 Jun 2005 22:35:05 -0700
[resending as I forgot to prune the history to make the listbot happy]

> After reading that you paid for a tow, I don't know if this is good  
> or bad news, but my impression is that all the 300ZXs smoke on  
> course, something to do with overflow from the breather.  Hopefully  
> Carl Merritt or someone as knowledgeable will chip in with an expert  
> opinion, but all the ones I've seen smoke like chimneys, and it  
> seemed to be a known and harmless issue to their owners.

Yup, Z32 300ZXs (the latter model, '90-96) has a bad habit of sucking oil into 
the intake through the PCV system.  It's easiest to do when you lift off 
throttle at high RPM and turn in hard to the right, simultaneously sloshing oil 
up towards the driver's crank vent port and providing lots of intake plenum 
vacuum to suck the oil in.  This can cause immediate SpyHunter style smoke 
screens, or sometimes a delayed action routine as the oil trickles down through 
the plenum:
http://www.zfilms.org/Stories/Z32/2001/1-1/Parker4.jpg

This behavior, while not necessarily healthy, isn't really a bad thing.  
Eventually it'll foul your nice shiny platinum plugs, and can also promote 
detonation which will either loose you power or could in a worst case blow your 
motor up if it's a turbo and you're running lots of boost.

In many many years of autocrossing such cars I've only ever seen one critical 
failure.  A wild spin without depressing the clutch ended with the drive wheels 
dragging the motor backwards.  This caused an oil vacuum spike which sucked the 
oil-filter bypass check-ball out of it's cage and back into the oil pump where 
it went CRUNCH:
http://www.zfilms.org/Stories/Z32/1999/AutoX/06-2627/dennisoilpump.JPG

The remains of that oil pump is probably still on display at Dando's 
Performance up in Fremont.  Unfortunately the motor which it was attached to, 
starved of oil pressure, ate it's bearings while the driver idled it back to 
the paddock.

-Carl






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