Is the timing correct based on these photos.

[cbova]

Don't forget 1 notch on the crank is different than 1 notch on the cams.

Are you sure?
One notch on the crank would have to be the same amount on the cams because the belt would make the notches move the same amount. The reason the crank makes 2 revolutions when the cam makes one is because the cam has twice as many notches.

Sure, that's precisely the principle. Imagine if you had a 1000 tooth sprocket and a 5 tooth sprocket connected by a chain. When you're lining up marks moving 1 tooth on the large sprocket is not the same as moving on tooth on the small sprocket. I would start my getting the crank dead nuts and TDC and see where the cam marks are.

[- Pete -]

^^^
That’s what I was trying to say. Thanks for that.

You’re super close, just get that crank exactly right, then assess the cam sprockets. From the looks of the camera’s vantage point, it (crank) needs to roll CCW half a tooth. Regardless of this, if your exhaust cam is lined up properly, the engine will run given your current timing alignment. If it rolls over by hand without any hard stops, you won’t have valve to piston contact.

The intake cam (on 2.4T) is not monitored by the ECM, the exhaust is, however. If you are off far enough for the ECM to catch it, it’ll populate a code, even though it may idle & run good. Then you’ll know if you need to make adjustments.

[02V70]

You’re super close, just get that crank exactly right

The problem is I can not tell if it is correct because it is hard to see the marks with the belt and belt tensioner on, and the angle i am viewing it at makes it seem not aligned.
this video:

says this

Screen Shot 2022-03-14 at 5.17.17 PM.png (1.54 MiB) Viewed 983 times

Screen Shot 2022-03-14 at 5.17.45 PM.png (1.67 MiB) Viewed 983 times

"When you're lining up marks moving 1 tooth on the large sprocket is not the same as moving on tooth on the small sprocket."

I dont understand why it is not the same. Since the groovs on the belt match the grooves on the sprockets, when the crank moves one tooth compared to the alignment, the cam must also move one tooth right?

Im confused...

[cbova]

Since the groovs on the belt match the grooves on the sprockets, when the crank moves one tooth compared to the alignment, the cam must also move one tooth right?

Im confused...

yes, BUT 1 tooth is not that same rotation amount for each sprocket. One tooth of a 360 tooth sprocket is 1 degree, 1 tooth on a 180 tooth sprocket is 2 degrees.

[02V70]

yes, BUT 1 tooth is not that same rotation amount for each sprocket. One tooth of a 360 tooth sprocket is 1 degree, 1 tooth on a 180 tooth sprocket is 2 degrees.

I understand that, but why is this important other than that it means I have to turn the crank twice for the cams to turn once... Or was that the point you were trying to get across?


Suppose that cams and the crank were in time with each other. If the crank was positioned so that it is 1 tooth/groove to the left of the timing mark, then the cams would also have to be 1 tooth to the left of the timing markings right? The problem I have is that if the cams are on the timing mark, the crank looks like it is half a tooth away from the timing mark. I don't understand how this would happen, so I think the timing is fine, and it is just the viewing angle that makes it look like that, but I was not sure, so I asked the question here.

[02V70]

Yep, off by one.

I turned the engine over again, and aligned it better (I never took the belt) it all looks aligned now. Did you just mean everything was off by one? Or do you know for sure that the cam and crank are one groove off from eachother.

[jonesg]

yes, BUT 1 tooth is not that same rotation amount for each sprocket. One tooth of a 360 tooth sprocket is 1 degree, 1 tooth on a 180 tooth sprocket is 2 degrees.

I understand that, but why is this important other than that it means I have to turn the crank twice for the cams to turn once... Or was that the point you were trying to get across?


Suppose that cams and the crank were in time with each other. If the crank was positioned so that it is 1 tooth/groove to the left of the timing mark, then the cams would also have to be 1 tooth to the left of the timing markings right? The problem I have is that if the cams are on the timing mark, the crank looks like it is half a tooth away from the timing mark. I don't understand how this would happen, so I think the timing is fine, and it is just the viewing angle that makes it look like that, but I was not sure, so I asked the question here.

If you move one tooth on the small gear you will have to move many teeth on the larger gear to avoid a loose belt.
That's a principle of gearing.

If you move one tooth on the crank and one tooth on the cam, the belt will not be tight. Any slack is taken up after the Cams, but between the crank and cam sprockets you cannot have any slop.

That's why the spring loaded tensioner is positioned where it is and not between the crank and cams.

[abscate]

You also have to move the belt , then turn through a complete revolution to equalize all the dlack on a VVT CAR

[erikv11]

The half-tooth-off phenomenon comes from a stretched belt (old belt) or uneven tension on na new, installed belt. The teeth will all be in phase once you get new pieces installed.

...
If you move one tooth on the small gear you will have to move many teeth on the larger gear to avoid a loose belt.
That's a principle of gearing.
...

Nay. One tooth movement on one gear is one tooth movement on any interlocked gear, whether in direct contact or connected by a toothed belt. The principle of gearing you may be thinking of refers to the number of rotations when the gears are different sizes (diameters). But one tooth movement on one gear is one tooth for any other gear in the chain. That's the whole point of gearing!

Or maybe you meant something else, in which case i digress ...

...

If you move one tooth on the crank and one tooth on the cam, the belt will not be tight. Any slack is taken up after the Cams, but between the crank and cam sprockets you cannot have any slop.

That's why the spring loaded tensioner is positioned where it is and not between the crank and cams.

This, however, I agree with. And it helps explain why the tensioner allows the half-tooth-off phenomenon to arise with a stretched timing belt.

[jonesg]

The half-tooth-off phenomenon comes from a stretched belt (old belt) or uneven tension on na new, installed belt. The teeth will all be in phase once you get new pieces installed.

...
If you move one tooth on the small gear you will have to move many teeth on the larger gear to avoid a loose belt.
That's a principle of gearing.
...

Nay. One tooth movement on one gear is one tooth movement on any interlocked gear, whether in direct contact or connected by a toothed belt. The principle of gearing you may be thinking of refers to the number of rotations when the gears are different sizes (diameters). But one tooth movement on one gear is one tooth for any other gear in the chain. That's the whole point of gearing!

Or maybe you meant something else, in which case i digress ...

...

If you move one tooth on the crank and one tooth on the cam, the belt will not be tight. Any slack is taken up after the Cams, but between the crank and cam sprockets you cannot have any slop.

That's why the spring loaded tensioner is positioned where it is and not between the crank and cams.

This, however, I agree with. And it helps explain why the tensioner allows the half-tooth-off phenomenon to arise with a stretched timing belt.

Here's the way out of the confusion.

He isn't moving just the belt, he's moving the smaller gear , the crank, =relative= to the other larger gear.

Just moving the belt one tooth accomplishes nothing.