Tonight I attempted to adjust the timing on my 53 1/2 ton GMC and noticed the timing ball was jumping around. It was moving left and right about 2 ball widths. I tried to search here for an answer but could not locate a similar thread. What could be causing this?

Also, when I start the truck I can hear a clacking noise. I read several threads that recommended using a little marvel mystery oil to clean out the guide paths. Where would I squirt the oil? In the cylinders?

Thanks for all your help,
Dale

When I die, I want to go peacefully like my Grandfather did, in his sleep -- not screaming, like the passengers in his car.
-Unknown-