[Vwdiesel] Valvetrain advice

[Robert Downes]

Hi Folks! though i rarely take part in these discussions, i've been a
subscriber to this list for a long time and have a great respect for the
spirit of community brought by some of you here. i find this community to
be one of the biggest perks of owning these cars and i'm keenly aware of
how much i've learned reading this list in particular.

Thanks A Lot!!

And now, the point: I have a 1.9D (1y) engine in my '81 caddy. great
engine, i've never regretted putting it in. i got it for a good price with
unknown miles and have gotten my money's worth out of it but the
noisy/smoky valvetrain finally got bad enough and the timing in my life got
good enough that i recently converted my head into an organized pile of
bits. i have pretty good help here from a machinist with with space and
tools to loan but i'm having trouble finding complete information online to
help me evaluate my parts and determine exactly how far i need to go.

i definitely need new guides, and those are readily available. this head
has the older, 8mm valves and i also have a source for a set of those.

the seats and valve surfaces are clean and shiny, but are visibly worn out
of shape (from the worn guides?)

my questions are,
--i have access to seat grinding tools and help from a machinist to grind
the valves flat. how can i determine whether the wear is too much? that is,
what is the range of self-adjustment of the hydraulic lifters and is there
an established baseline to measure from?

--i've seen some nonspecific recommendations against reworking these
valves. my valve stems are not worn measurably (the dia. is consistent to
.0005" over their length) and i'd love to avoid buying a new set. how
foolish would it be to grind them? if the answer is not very, what angle
differential  with the seat is normal?

--i have a proper drift for removal/installation of the guides, and an idea
of how to go about that job, but I WELCOME any tips that any of you might
have to ease this part of the work. also, the guide reamer i have is the
adjustable variety. is there a target value to ream these to? i've found no
info except to use the vw reaming tool. my best guess is to go until there
is a small amount of 'rock' via the guide wear test in the bentley manual,
but much less than the 1.3mm max. ???

I hope that's reasonably clear. Thank you in advance for the help, and in
return i promise to get a little more active and help field some questions
that are within my sphere!

with Gratitude
-Bob
Port Townsend, Wa