Camshaft Gear Must Be Off (Misaligned)

[Oka]

2001 Volvo XC70

Hello folks. Been a while I parked this car, which is my fav of my Volvos.

When I finished working in the car, towards the end of '21, I put everything together and got so disappointed. Initially, as I had reported, it sounded like a nut or alike fell into the engine at the first start of the engine; I stopped it right away.

The ONLY culprit to my dilemma will be that I messed up with the Camshaft work. I did not remove it, just used the Camshaft Position Sensor Locking Tool to hold it in place. I marked the belt and the gear, when putting things back, I lined the paint marks I had to have the gear teeth to align at their original positions.

Definitely, I did not do it right. That will be the only reason the starting was that bad. The miss aligned gear teeth made the noise I heard when starting.

No doubt fixing this will only be possible by a Volvo specialist. Right? There's a reputable local one in town.

Cheers

[Astro14]

From your description, I think you did screw up.

Did you have a source, Vida, perhaps, for how to do this?

Here is what I believe is going on. When you lock the camshaft, you have defined its position. When you lock the timing gear, you define its position. That works great on the intake cam. For your year, the intake cam does not have variable valve timing.

However, your exhaust cam has variable valve timing. That?s why the gear looks so much different.

With variable valve timing, you have three things that need to be in the correct relationship, the camshaft, the timing gear, and the internal lobes of the variable valve timing hub.

Service information for the car will tell you how to advance the cam, or retard the cam in order to get that internal lobe in the correct position. Then, and only then, can you set the external gear to the correct position. Once you lock the internal lobes Onto the cam, you?ve defined the relationship between all three. But unless you follow the service information steps, your cam is out of position in relationship to the gear because it?s allowed to swing back-and-forth on those lobes.

So, I would dive back into that exhaust cam, make sure it?s done correctly. I am in Colorado, and don?t have my VIDA machine with me, but you need to find the service information on setting the VVT hub up correctly.

[Astro14]

Photo taken during a cam seal replacement. Crank and intake cam are in the correct position. Exhaust cam is in the correct position. Cams are locked from the back with the cam tool.

But, remove the timing belt, and the spring inside the VVT hub moves the cam, as shown. See how it no longer lines up with the notches in the cover?

So, upon re-install, you have to move the hub full clockwise, tighten the bolt and check.

[Oka]

Photo taken during a cam seal replacement. Crank and intake cam are in the correct position. Exhaust cam is in the correct position. Cams are locked from the back with the cam tool.

But, remove the timing belt, and the spring inside the VVT hub moves the cam, as shown. See how it no longer lines up with the notches in the cover?

So, upon re-install, you have to move the hub full clockwise, tighten the bolt and check.

I have set to start on this car next spring, as soon as the weather clears, and find a way to move it into the garage. Wish I posed this question earler this year. I will revisit all the posts here and start. Surely, will give an update.

Thanks for the info, well appreciated!