Hans Neureiter wrote:
Since the valve adjustment job is fairly easy but a PITA, why not adust the
valves a bit looser than specs, i.e. .005"/.015" instead of .003"/.013".
This would throw the timing off a hair, open a little later and close a bit
sooner. But will it be significant enough to notice?
The benefit being longer intervalls between needed adjustments since they
always tend to tighten up.
A well maintained engine lubricated with good oil that's changed as
required, will not need adjustment very often, but they still need to be
checked before each cold season to insure flawless cold starting. The
process is far from linear and often changes quite suddenly! Once you
have become "one with your car," you may be able to tell that the valves
need adjustment from the sound, but I was never able to count on that
even after 20+ years of trying. Increasing valve clearance will make
them noisier, increase wear (at least a little) and the engine won't run
as well. Tight valves quiets the engine, but results in slow/no cold
starting, poor running when cold and excessive valve wear/damage.
Valves can tighten (usually intakes) with wear (and that prevents cold
starting) and they can also loosen (usually exhausts) and that makes the
engine noisier, but neither of those results are exclusive - so they
really must be checked every 15kmi or so and adjusted if they are out of
specification.
It's been reported (rather frequently) that the use of Mobil synthetics
will reduce the need for valve adjustment (but I don't know why that
might be). I KNOW it reduces timing chain wear (I've measured that) by
about half and I understand why, but I can't figure out why it would
reduce the need to adjust valves.
Marshall
--
Marshall Booth (who doesn't respond to unsigned questions)
"der Dieseling Doktor" [EMAIL PROTECTED]
'87 300TD 182Kmi, '84 190D 2.2 229Kmi, '85 190D 2.0 161Kmi, '87 190D 2.5
turbo 237kmi
