Bill!
8 to 5 you have a fiber timing gear going south (coming loose on its steel
hub). This is a VERY common occurrence. There are timing gear sets on ebay
all the time and you could go with a new fiber gear or a steel timing gear
set. (If you go with steel, you have to change both gears because they are
a different pitch in the teeth.)
This has happened to me on almost every red Volvo engine I have had. It is not
a big deal to change but you need either a 15 inch Crescent wrench or a
1 7/16" socket or box wrench for the nut on the end of the camshaft.
A 3-legged puller for the timing gear helps - I made one out of a triangular
piece of plywood and 3 carriage bolts with the heads ground eccentric. When you
replace the gear you should also replace the brass plate behind it, which with
the steel ring behind the gear and its woodruff key, establish the forward/aft
location of the cam in operation.
--
George Downs Bartlesville, Heart of the USA!