Timing belt walking off pulleys after resetting timing marks and tensioner

SCP74 · Post by **SCP74** » 24 Jun 2020, 20:09

Having issues after adjustment of timing marks. 02 xc70
There are no symptoms of anything wrong, car starts on 1st crank now, whereas before I was getting CEL. So now, the belt is moving off the pulleys, off all the pulleys. There is no wobble in my vvt, and I've set the tension already 10 times at every level of tension, and it still is moving off the pulleys. And right away after turning over, it's already and eighth of an inch off the pulleys.

Post by **SuperHerman** » 25 Jun 2020, 01:15

Check your work. What did you take off? Is the harmonic balancer or gear correctly seated? What parts did you replace?

Post by **jonesg** » 25 Jun 2020, 05:09

SCP74 wrote: ↑24 Jun 2020, 20:09 Having issues after adjustment of timing marks. 02 xc70
There are no symptoms of anything wrong, car starts on 1st crank now, whereas before I was getting CEL. So now, the belt is moving off the pulleys, off all the pulleys. There is no wobble in my vvt, and I've set the tension already 10 times at every level of tension, and it still is moving off the pulleys. And right away after turning over, it's already and eighth of an inch off the pulleys.

Walking off the pulleys =IS= the symptom.

Mine was doing that last week, I shut it down and disconnected the battery to begin with.
Traced the cause to wobble in the crank pulley, damaged splines due to missing 30mm crank gear retaining nut.
New pulley is arriving today.
To detect wobble by hand you need to pull the timing belt off.

Post by **oragex** » 25 Jun 2020, 07:46

There can be two things: belt riding on the side of the pulleys, and belt 'walking'. I'm assuming OP has the 'riding on the side' ? If so, does a width of the belt ride completely off the pulleys, or rather just at the side of pulleys ? If just at the side, I would leave it there. I had both these issues when the tensioner I used had a problem, with a new one both problems went away, and my belt now is not walking any more and stays 'almost' at the center. Of course, there could be other things than the tensioner - as shown above. The water pump is also worth a check. Also make sure tensioner center bolt is at 15 ft-lb, which is not a lot for a 14mm bolt, some garages may put much more - perhaps 30-40 ft-lb which causes perhaps the tensioner to deform slightly and start wobble or push the belt to ride to one side. I'm not sure if correcting the bolt torque on a tensioner will bring things back to normal.

Post by **chrism** » 25 Jun 2020, 11:09

Idler pulley not sitting flush against the engine block?
Did you temporarily have the belt removed? Did it maybe get reinstalled in the opposite direction? (Guess it shouldn’t matter, but.........)

SCP74 · Post by **SCP74** » 25 Jun 2020, 16:20

Oragex, it is off the pulley by like 1/8 in. And that is directly after startup. The steel which hangs on the ridge of the motor is bent and has been from the the moment I tensioned it the the first time weeks ago. Can a bad tensioner cause the belt to move that much? Could I have damaged the tensioner by moving the ecsentric the wrong way? Sounds like trying with another tensioner will tell me.

Post by **jonesg** » 25 Jun 2020, 22:21

SCP74 wrote: ↑25 Jun 2020, 16:20 Oragex, it is off the pulley by like 1/8 in. And that is directly after startup. The steel which hangs on the ridge of the motor is bent and has been from the the moment I tensioned it the the first time weeks ago. Can a bad tensioner cause the belt to move that much? Could I have damaged the tensioner by moving the eccentric the wrong way? Sounds like trying with another tensioner will tell me.

if the tensioner was slightly out of position when you tightened it, it could have bent the tab..
Or over-tightened , the tensioner I pulled off my engine had a bent tab too, it was way over torqued by a mechanic.
but the belt drift was caused by a bad crank pulley, so don't presume its fixed until you can see its fixed.

06S60 · Post by **06S60** » 29 Jun 2020, 13:09

Recently installed a new TB kit and had the same issue of the belt walking off during my manual hand crank check.. After a lot of checking and removing and refitting turned out I cracked the new TB tensioner base by over torque

. It was very hard to notice at first only removed it because I thought the tensioning spring was broken then I noticed the cracked base...

Post by **vtl** » 29 Jun 2020, 15:21

Conti belts also like to walk on the pulleys. Had two of these. Replaced with Volvo belt and all is good.