acme,
I'm like a bulldog..I'm not going to let go! If you draw a cartoon of the 4 strokes of the engine, it becomes obvious that in order to pop back through the carburetor, the intake valve must be open. On this stroke, ignition would not be an issue.
Did the truck not do this before, and now it does it..was something changed or replaced. You did a whole bunch of work to the engine. Were you trying to solve this problem.
I am assuming you have an air cleaner on the truck..is the backfiring through the carburetor severe, as in loud and flaming! Is it an actual explosion, or just a puff of moving air.
The slop in the distributor just isn't enough to cause what you describe. Have you ever thought about dumping some top end cleaner like Berryman Chemtool into the carb to douche the carbon!
As I usually state when I am confused, something is really rotten in Denmark on this one!
This backfiring scenario would require some fuel, and an ignition source...timed when the intake valve was open. Should be easy to figure out HUH! :confused:
Stuart
