Two parallel vertical valves per cylinder are driven directly by a single overhead camshaft.
In the picture to the right, at the free end, one can see the vertical shaft which drives the camshaft.
This engine was the first in a Fiesta to feature an overhead camshaft instead of the usual overhead valve format.
This is done by rotating the camshaft ahead a few degrees.
Then there was a move to a flexible timing belt rather than chain drive for the overhead camshaft.
The first new camshaft failed in use, as did two replacements.
There should be basically no slack in the chain as it runs from the camshaft chainwheel down to the crankshaft chainwheel.
If there is slack, carefully remove the camshaft chainwheel, and replace it on a differnent keyway.
This was a nice lazy six, looking good on paper but sportscar road testers complained, citing poor camshaft timing and breathing problems.