UR-q blue smoke.

[ggthack@swansea.ac.uk (Graham Thackrah)]

I'd be interested in knowing how to perform a leakdown test on my car.
The reason is that I have a smoke problem that was put down to valve stem
seals but wasn't solved on having them and the guides replaced. It doesn't 
noticeably smoke more or less when warm or cold.

The problem is only on overrunning; a brief puff on very hard up changes
(c. 6500 revs) and when decelerating from high revs (such as lifting off the
gas on the motorway or going down hills off the gas). I'd like a good idea
of the likely source of the problem before I go ahead and take the head off
again or remove the engine to have a rebore.

The head had new valve stem seals, valve guides, recut valve seats and the
face skimmed at the same time, this had no noticeable effect on the symptoms.
I don't discount a bad job of replacing the seals btw.

The compression values are within specifications from a post to hte list 
previously (c.150 psi, +10psi wet). I am unsure how to perform a leakdown test 
that would show up if the bores are worn? I guess the procedure is to pressurise
the bore and check how long it retains pressure but how? I have a compression
guage, do I need a pressure guage without a one way valve to do this?

As soon as I get my car back home (it is parted from me at the moment, sniff)
I plan to try solvent in the bores to see if it is a stuck oil ring as it is 
due an oil change anyway (sorry Jim, still haven't got round to it yet!)

The engine is a NA I5 2144cc kk with 120k on it in an 84 80 quattro.

Thanks in advance.

Graham.

84 80 quattro.