More Code 2111

Bernie Benz b.benz at
Sat May 21 18:55:58 EDT 2005

Hi Alan,

IMO timing belts don't stretch, at least not to the degree that you imply.
But on the 20V dual cam engines they must be adjusted initially tight enough
to move the operating point well up into the very steep linear part of their
force deflection curve to avoid the dreaded distributor rattle.  The
resulting torsional cam vibration resulting from a loose belt is the
principle cause of distributor drive gear and chain wear in 20Vs.  I have
not witnessed either @ 200K.

Independent of all this, at any point in time the distributor timing mark
must be congruent with the TDC timing mark.


> From: "alan cordeiro" <alancordeiro at>
> Dan,
> It appears your problem is growing worse over time, this
> may be an indication of the distributor Hall-effect sensor being
> right at the edge of the timing window where the ECU must
> also see the pulse from the flywheel sensor.
> Besides timing belt stretch, another source of SLOW creep
> of timing error is wear in the nylon gear where the
> distributor shaft gets driven off the secondary cam.
> Come to think of it, there is probably a few degrees
> between the primary and secondary camshafts
> accumulating slowly as the timing chain grows old.
> Alan
>> Thanks for the tips Jonas! The car is due for a timing belt change, so
>> I'll check out all those areas you recommended. But perhaps the sensor
>> is just on its way out. I'll check out the signal then.
>> Thanks again-
>> -- 
>> Dan Cordon
>> Mechanical Engineer - Engine Research Facility
>> University of Idaho
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