ticking over 2000 rpm

["Ed Shiers" <mamn97@dial.pipex.com>]

Driving my car this morning  I noticed a ticking noise from the 
engine when accelerating slowly occuring through the lower rev 
range up to about 3,500 rpm.
I've heard this noise before occuring at below 2000 rpm when 
accelerating but never thought  anything of it since it's also audible 
on my parents golf. I assumed it was the 'piston slap'(?) . I had a 
feeling that it was beginning to happen furthar up the rev range.
There doesn't seem to be any blue smoke although the air filter 
gets covered in oil.
Yesterday the car had been driven very hard for around 60 miles so 
am not sure if this is a coincidence.
please don't tell me the engines had it as i'm very hard up!
p.s. don't think it's the exhaust manifold as i've just repaired a 
friends and the noise was slightly different.
TIA
ed
80 sport
220,000 miles