I've run into an interesting dilemma. I'm doing my timing belt / water pump on my 98 Mazda 626 2L and am at the point of putting the belt back on, but something has come up.
I checked my timing marks before taking the belt off ( and a few other times for other reasons ) and always assumed that everything was OK, as to my eye it looked like the timing marks were aligned.
However, as I was putting the belt back on and looking at the Haynes manual I noticed that it said the timing marks should align even with the surface of the head. However my marks were aligned one sprocket tooth below the the surface of the head. Of course you can hardly see anything in the Haynes manual pictures, so I took a look in the WSM:
That picture indeed seems to show the marks aligned with the surface of the head. However some of the other WSM graphics are less clear and to my untrained eye seem to show the marks aligned slightly below the head surface:
I've been dogged by a rough idle which I can't seem to solve ever since I bought this car, and I have no idea who the last mechanic to change the belt was, although I am sure it probably was the lowest bidder, let's say.
This is a non-interference engine, so it's quit possible it's been running with a slight misalignment of the marks for years without any physical damage.
As a novice, my question is do I leave well enough alone, or take a chance and rotate both cams up one tooth so the marks are dead on with the head surface like the Haynes manual says?
POSTSCRIPT Nov. 10th 2016
So I went ahead and made the marks align with the head surface, ran the engine for a few minutes and it seems to be OK:
