<VV> what causes a dead cylinder

[djtcz at comcast.net]

----- Original Message ----- 
From: Randolph Perry < rmperry.65 at gmail.com > 
To: vv-help < vv-help at corvair.org > 
Sent: Sun, Apr 3, 2011 7:40 am 
Subject: What causes a dead cylinder? 


I have found another nice car locally (read that near Augusta, GA., where I currently reside), 1966 Corvair Corsa, 140/4, fresh paint, new tires, new weather strips, fuzzies, carbs rebuilt, compression checks on all cylinders good, just one problem, number 1 cylinder is skipping, took the plug wire off while running, didn't make a difference in the way the engine ran. Any suggestions? Even if I don't end up buying the car, would like to help the gentleman that currently owns it out! 


================================ 
To me a list of what might cause a particular problems is a shopping list of 98% un-necessary purchases and parts replacements unless it is backed up with a list of how to test if a problem really exists on my engine. 


What would happen if a spark plug was soaking wet with gasoline, or had a heavy layer of conductive deposits, or deposits that filled the plug gap? 
What would be a good test for that? 


Where would the spark go if someone removed the wire from a fuel soaked/shorted plug with the engine running? 


What would happen if the distributor cap had a "carbon track" that lead to ground from the plug terminal that fed one cylinder? 
What would be a good test for that? 


What would happen if the distributor shaft and bushings were so worn that the points cam could move sideways far enough the points would not open, and the loading on the distributor shaft made that happen when the rotor was point to cylinder number 1? 
How could I test for that? 


What if the points were badly worn, so the point gap was about 0.002 inch, and 1 points cam lobe was about 0.002 inch shorter than the others? 
How could I test for that? 


What would happen if a plug wire had an internal break in the conductor that made it impossible for the spark to reach the spark plug? 
What would be a good test for that, and differentiate between a loose fitting wire boot that let conductive mung form a film across the cap or along the wire to some metal surface? 


If there was a significant intake leak (carb base gasket or some vaccuum fitting) the idle mixture near one cylinder could be much leaner than the others, and might even be so lean it was incombustible. Is there a test for that? 


I know you said the compression was "good," which would tend to eliminate 2 of the next 3 possibilities 
What would happen if an exhaust valve had burned to the point it would not seal? 
What would happen if a valve had been adjusted so tight the hydraulic lifter was holding a valve off the seat? 
What would happen if a cam lobe and lifter was wiped out, so that valve just barely rose off its seat? 


Was the compression check the highly questionable thumb-over-the-hole variety, or measurements made with an official gage? 
VW dealers used to measure and printout instantaneous starter motor current draw as a means to evaluate compression.