The more I think on it, the more I think running
the PCV vapors into #4 is the problem. Those
vapors have so much oil and other stuff in it, that
it would carbon up and caramelize the cylinder,
valve, seats, etc. A compression test may not
pick this up. The only hint might be that the
compression is high. The plugs may give you
a clue. They make spark plugs that will fire
oil. I would try one and see if it helps. If so
you have found the problem.
You are going to have to route the PCV somewhere
there is vacuum to the base of the carb where it
can be equally distributed to all 8 cylinders.
If you can't find a place to run the PCV hose,
you should remove the PCV hose and put
oil breathers on BOTH valve covers. I hope
you don't live in some bureaucratic state like
CA that will castigate you for doing this.
Dave Johnson
|