<VV> Opinions on compression

[Guus de Haan]

Last Sunday we wanted to take the Corsa to a classic car event. With  
the fuel problem solved I was kind of hoping on some driving fun. We  
took the highway because that is the quickest route. Even at 60 MPH  
it is running over 400F. I decided to take the secondary roads back  
home but it began to run worse and worse. I was convinced it was  
running on 4 cylinders or less. Spitting and popping and running very  
rough. In the evening I installed a pair of other (used) spark plugs  
but it ran just as bad. The old spark plugs look pretty good, even  
grey color, not carbonned up or or anything like that.

This engine had a turbo rebuilt because a chip of the impeller was  
missing and it was carboned up. I never found the piece and was kind  
of expecting it to be inside a cylinder somewhere ruining some  
valves.  I was planning to remove the heads coming Saturday but  
decided to do a compression test first. I expected to measure low  
compression on one or more cylinders. The engine has not been driven  
much since its rebuild but I was surprised the values weren't to bad  
at all.

1 - 12
2 - 9,5
3 - 11
4 - 10+
5 - 11+
6 - 10+

What's your opinion on these figures?
Cylinder 2 is lower but I would not expect the engine to run that bad  
because of this.

The Air/Fuel ratio according to the SafeGuard is pretty good when  
driving.

My guesses:
The valves are set to tight and stay open when the engine really  
heats up.
The distributor (one of the few pieces not rebuilt) is failing somehow.

Sorry for the long post but I really appreciate any advice (and of  
course moral support ;-)

Guus
The Netherlands
'65 Corsa Turbo-Charged Cvt