<VV> misfire (technical)

[Michael Kovacs]

 This is a new one on me. I knew I had a misfire or weak cylinder. I had just completed a partial overhaul (balanced pistons, rods and head work) on the engine, 140 4 speed . I was sure that # 4 was not firing properly (wet dirty plug) and it appeared to have low  compression.
   
   Today I did a  new comp  test of the #2,4,6 cylinders They were 190, 180, 190. Next was to pressurize all 3 and see if I could find a valve leak. There was no apparent leak in the intake or exhaust and the leaking air in the crank case seemed to be the same for all 3 cylinders. 
   
   I put the linkage, spark plugs & wires back as they were and decided to run the engine. Sure enough on initial start up the left side still pumps cool exhaust while the right side was warm . After it warmed up a little the left bank was definitely not as hot as the right bank and the exhaust still had a misfire sound on the left bank and smelled rich.
   
   I then discovered that when I checked with the timing light on 2 & 6 that there was a steady pulse. However #4 had a steady pulse only near the distributor and an interrupted pulse near the spark plug. It obviously was not firing all the time. What the heck is up with that?
   
   The wires are brand new 7 mm from reputable vendor. Is there a possibility the wire is broken internally? The plugs are also new r44.
   
   I'll try a used spark plug wire and spark plug and check the distributor cap for a crack or any carbon tracking, but it too is new to suspect that yet.
   
   I wont hold the #4 spark plug wire to see if it is leaking voltage! All the spark plug wires are separated with plastic wire looms.
   
   Does anybody have a better suggestion? Comments?


MIKE KOVACS