Does the timing belt marks always line up at TDC? I put on the new belt, lined up all marks and rotated the engine until it hit TDC again and the marks no longer line up. Are the marks there just for installation?

 

Only every 2nd TDC in the same rotation direction can see the marks line up

Thinking about it the crank sprocket is way too small so it wont realign in 2 engine rotations already - probably more like 4 rotations. Those marks are basically only used for initial alignment/timing of the cams relative to the crank.

 

That's what I thought, because I rotated the engine several times and I couldn't get them to line up.

 

they will not line up again. the marks are only there for installation only. once you install it the first time with the marks at the correct timing marks you will be fine after that. so don't worry about the marks anymore after you rotate the engine after the new belt has been installed.

 

What he said. I pulled the plugs out of one car and turned it about 40 or 50 times trying to get them to line back up again, and never saw them land exactly on the right tooth again. Eventually they will, but it's going to take a loooong time.

 

1994 nissan maxima 3.0 timing marks trying to set at 15 degrees btdc. has 7 marks which one is 15
and what does the frist mark stand for and the last one and each one so i would have an idea

 

Middle mark is 15 degrees. It sarts from the left at zero degrees and each mark is an increment of 5 degrees.

 

It doesn't matter as long as all the marks were lined up at the installation of the belt.

 

144 turns will get them lined up again i think... cuz that's how many teeth are on the belt. mathematically there are no common factors (43 is a prime number isn't it?) which is why it takes so damn long to make them line up again.

well that's the spark timing, not the valve timing, but the first mark is gonna be 15BTDC and the last mark will be 15ATDC

 

You really don'y need the marks, it's to make it easier on the DIYer......

 

they help though, because they are calibrated for the belt in its slacked state. once it's tightened the dots on the cams appear to be a half tooth off from one another due to the lack of slack, which if you didn't use the lines to begin with, can cause an inexperienced installer to possibly install the belt with one of the cams a tooth off if they don't reason that the cams dots will move apart slightly once the belt is under tension.