[V6-12v] Resetting Valve Timing, etc.

[James4ihl at aol.com]

Hi Guys --

Wondered if I could benefit from your automotive wisdom once more...

This is mainly concerning valve timing and noisy tappets (hydraulic lifters). 


I have a noisy tappet somewhere. It's OK most of the time, but when I get up 
to sustained motorway speeds (which I don't often do as I live in an area 
which is mainly country lanes) it begins and only dies down after a mile or so at 
lower revs. My mechanic has recommended running some tappet flush through the 
oil, as it's having an oil change on thursday anyway. However, if this doesn't 
work, are the tappets a job one should attempt oneself? I understand the job 
in theory after looking in the manual, but I've never actually done tappets 
myself, so I was looking for the benefit of experience here. If it's a tricky 
job, I'll let my mechanic do it.

Regarding the valve timing, it occurred to me that you'd have to loosen off 
the cam sprockets and remove them in order to pull the camshafts to do tappets. 
You may recall a hesitation problem (I may have mentioned it just a couple of 
times!) I've been having. Now here's a thought because I suddenly recalled 
that the garage where I bought the car (non-Audi dealership) not only replaced a 
timing belt, as I've mentioned before, but also replaced a tappet or two. Now 
I've speculated previously that if they did the timing belt replacement 
without the special tool to hold the cams in position, they may not have got it 
spot on, although other members have mentioned methods they could have used to 
get it close enough that no actual damage would be caused. Well, if they had to 
loosen off and remove the sprockets to pull the camshafts and do tappets, they 
couldn't have used any of those methods so they CAN'T have got it spot on 
without the special tool, right? The thing is, where those sprockets are 
infinitely adjustable on the cams, they could have got it slightly out, even on one 
side, so I'm going to have to check it anyway. I'll eat my hat if they had 
access to the special tool in that workshop (they were a bit dodgy, in 
retrospect)... In everyone's experience, could being slightly out on valve timing cause 
occasional hesitation? I just recall that when I test drove the car, there was 
none of this running problem which I first noticed after I bought it 
(naturally!) which was also after they'd done the timing belt/tappet replacement.

Again, can I do the timing adjustment myself in a garage with not a lot of 
space, or am I better leaving it to a workshop supplied with my manual (I have a 
decent independent mech now)?

Thanks guys!
James