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Cam Shaft Wear

To: mgs@Autox.Team.Net
Subject: Cam Shaft Wear
From: Chris Delling <saschris@flash.net>
Date: Tue, 23 Dec 1997 14:30:54 -0500
Some info of general interest (of particular interest to rubber bumper B
owners).

I completed the removal of the camshaft in my 77B yesterday.  There are
approximately 70,000 miles on this cam.  Based on the flat performance of
the car, I sought out suggestions to correct this.  I was advised by
several sources that the cam shaft in the rubber bumper cars was prone to
advanced wear due to a relatively soft metal being used in it's manufacture.

I just completed a mechanical inspection of the cam lobes.  The stock cam
is spec'd with 0.250" lift.

Cylinder        1                       2                       3               
        4
           EXH     IN             IN      EXH             EXH      IN           
 IN        EXH

Lift:    .265    .162          .208      .245           .205      .228          
.190
  .268

I can't explain the high readings for the two exhausts on 1 & 4.  Perhaps a
bad grind.  I did check them three times.  Interesting the similarity
between 1&4, and 2&3.

What is not reflected in the measurements is the flat spotting, and extreme
pitting seen on 6 of the 8 lobes.  In the extremes, the worst lobes don't
even appear rounded any longer.  By the way, the lifters look almost new,
with no undue wear.

This certainly goes a long way to explain the lost sparkle in my engine
performance.  If you are driving a late B with more than 50,000 miles on
the clock, you may want to consider this.

Regards,

Chris Delling
 


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