Jerry,
The popping through the exhaust stopped after readjusting the valve to your procedure, so did that rear top cylinder clack/knock? Checked #6 exhaust valve movement with magnetic mount micrometer. The rise and fall of the #6 exhaust valve was within .001-.002 of the other exhaust valves as best I can see. What I am seeing is the # 6 exhaust valve moving slightly erratically like it is sticking. Removed all the spark plugs and turned the engine over by hand slowly. When # 6 exhaust valve opens and closed when the rocker arm comes up the valve is sticking down and popping shut, but not at all times. Checked for broken valve spring. Spring is good. Could be weak. Push rod is turning straight, no noticeable bend. Valve appears to be straight at the stem section as it goes up and down. Very little if any variance in the movement of the stem when it goes up and down. Just pops shut periodically one the rocker come to the up position. Valve sticking with carbon deposit in the guide? Should I try the MMO treatment or Seafoam?
Tim
