Testing intake for boost leaks.

[Matt twentyV]

> Several posts in the archives mention blocking the
> crank vent prior to
> pressurizing; how/where is this done?  Is the
> pressure leakage from the
> crankcase pressure regulator valve normal?  The
> leakage is from where the
> "lid" is joined to the base.  Since this vent should
> be blocked anyway, do
> these leaks affect boost?  (I'm guessing "yes"
> here.)

What I did was disconnect the fitting on the
breather hose at the regulator valve and clamp a
wine cork in the hose (leading to the turbo).  You
may want to loosen and lift up the turbo intake
pipe to facilitate access, but once you know where the
hose clamp is this step is no longer necessary.
Since the breather and regulator attach to the low
pressure side of the turbo, it shouldn't see boost
(and thus not leak boost).  But under vacuum it may
allow unmetered air to enter the intake and thus
screw up the mixture control.  If you have leaking
it is definitely broke and should be fixed.  When
I pressure tested with the breather attached I got
leaking out the spark plug holes (replaced VC gasket),
oil filler cap (replaced gasket) and dipstick (replace
O-ring).

Matt Rooke
'91cq//20vt
'00S4//30vtt

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