valve problem on 5000s

[Bruce Kaye <bruce.kaye@edrd.dnd.ca>]

Hi all. 

Here's a long story of how the Audi gods have tasked me again.  The wife's
car developed a rattle and I was quick to blame the cat.  I had to replace
the cat 4 yrs ago because of a similar noise so logically I thought it was
the it was the same thing.  I had replaced the oxygen sensor after the
first cat but 5 months ago found the "new" sensor had an intermittent short
and was pushing the engine full rich (poor gas mileage lead me to it).  
So the cat has been replaced (it was shot) and the loud rattle is gone but
on hard acceleration there is still a rattling type sound and the idle is
rough.  My mechanic suggested a bad injector and he checked them.
Conclusion poor spray patterns on three injectors but the sound was from a
leaky intake valve on # 5 cylinder.  Cost to do the head and replace the
lifters and injectors $1700.  My problem is what to do now.  Have the head
work done, replace the head with the one off my parts car or change engines
with the parts car? My car is a 86 no knock sensor, the parts car has the
87 130 hp single knock sensor engine.  What the best way to go keeping in
mind cost and time? (Mine or my mechanic's)

Thank for your words of wisdom.


Bruce 

87 5000CD Quattro Avant
87 5000s Avant (parts?/fixer-upper)
86 5000s Avant (wife's)
83 GPZ 1100
75 TR6