Timing belt tensioner shake

Post by **mrbrian200** » 15 Jan 2018, 19:53

Components around the accesory belt ruled out. You mentioned hubs, timing tensioner, timing pulley and WP replaced. Wobbled before the new parts installed, continues after. That leaves the engine, torque converter, or the rubber in the harmonic balancer is getting weak and springy.

Question for others:
Aside from the two belt chains, is there anywhere else in the engine where ball bearings are used? Could worn gears starting to bind up inside the oil pump, or something like a loose/worn connecting rod bearing, worn piston/slap, loose cylinder sleeve, or even something relatively mundane such as detonation, etc result in sharp changes in rotational velocity at the crankshaft? These are the sorts of things I think probably need to be explored.

Post by **cn90** » 15 Jan 2018, 20:32

I still think a bit of "shaking" is normal because of changes in the belt tension, caused by changing force needed to move the camshafts.

If you look at the video below, you will see that:
- At time marking 1:00-1:10, the indicator stays still in the middle as others said.
- However, at time marking 1:30-1:40, the TB is moved manually by the owner of the car, changing the tension, and this maneuver moves the indicator back and forth.

Every engine is a bit different, so I think it is normal to see some movement of the indicator.

Post by **jonesg** » 15 Jan 2018, 22:38

cn90 wrote: ↑15 Jan 2018, 20:32 I still think a bit of "shaking" is normal because of changes in the belt tension, caused by changing force needed to move the camshafts.

If you look at the video below, you will see that:
- At time marking 1:00-1:10, the indicator stays still in the middle as others said.
- However, at time marking 1:30-1:40, the TB is moved manually by the owner of the car, changing the tension, and this maneuver moves the indicator back and forth.

Every engine is a bit different, so I think it is normal to see some movement of the indicator.

Yeh, if the cvvt hubs are working then the ratio between the crank and cams is changing slightly , that difference has to be taken up and it's visible in the tensioner.

In the OP video they are blipping the throttle, the tensioner is expected to move.
If the tensioner didn't move then there would be a problem, either the tensioner , cvvt hubs or solenoids.

I suspect he's being spooked because the cover is off and it sounds louder.
I'd install the belt cover, close the hood and listen. If the noise is acceptable and all the acc belt pulleys feel good, I'd install the acc belt and listen again. If there's no cel I'd forgetaboutit.

Post by **oragex** » 16 Jan 2018, 03:55

jonesg wrote: ↑15 Jan 2018, 22:38 In the OP video they are blipping the throttle, the tensioner is expected to move.
If the tensioner didn't move then there would be a problem, either the tensioner , cvvt hubs or solenoids.

They do touch the throttle indeed, but when they stop revving the needle still moves and it doesn't just shake a little, it moves quite a bit.to the left I think it's not normal. With tge engine off, you need to push or pull with quite some force on the belt to have the needle move that much. A small vibration is not that bad, buth in the OP video there is too much movement. I wonder if the needle moves as it should with the engine off and pressing or pulling the belt between the two pulleys? Maybe PO could upload another video with this test.

mscgunaydin · Post by **mscgunaydin** » 16 Jan 2018, 07:44

I can think of a situation that will cause this problem. Could the performance of the oil pump be weakened?
Could the VVT Hub be unable to adjust due to low pressure?

Post by **jonesg** » 16 Jan 2018, 21:43

mscgunaydin wrote: ↑16 Jan 2018, 07:44 I can think of a situation that will cause this problem. Could the performance of the oil pump be weakened?
Could the VVT Hub be unable to adjust due to low pressure?

Yeh, wrong oil visc can do that too.
My cvvt valve was lagging and setting a code, oil change fixed it.

But I found the problem by reading codes, not by looking at the belt tensioner.

mscgunaydin · Post by **mscgunaydin** » 16 Jan 2018, 23:56

The tool was connected to the computer, no error code.

Post by **mrbrian200** » 17 Jan 2018, 01:15

About the CVVT hubs. Variable cam operation doesn't change the length of belt between either of the hubs and/or between the intake hub and the crankshaft. The angle between the outer hubs (part we can see) to the camshaft changes. Most people do seem to understand that, but then get a little confused about what is actually happening when they see movement on the tensioner. VVT operation does not create or decrease 'slack' that the TB tensioner would have to adjust to. Movement of the tensioner is due to 'other' (inertial changes, resistance to movement from anything physically connected which includes virtually all internal moving engine parts, and belt stretch). The tensioner is on the 'supply side' not under working tension.

nickbw898 · Post by **nickbw898** » 17 Jan 2018, 11:52

I'm sorry to say authorized Volvo workshop no guarantee work was done correctly. Check your alternator pulley it is AOC like this
https://www.gates.com/power-transmissio ... lley/c/138
SERVICE INTERVAL 100K miles or every other belt change £50 here

Post by **mrbrian200** » 17 Jan 2018, 21:17

nickbw898 wrote: ↑17 Jan 2018, 11:52 I'm sorry to say authorized Volvo workshop no guarantee work was done correctly. Check your alternator pulley it is AOC like this
https://www.gates.com/power-transmissio ... lley/c/138
SERVICE INTERVAL 100K miles or every other belt change £50 here

He started the car with the accessory belt removed and the TB tensioner still wobbled. Page 1, 15:27. Which means the alternator pulley isn't the culprit.

Timing belt tensioner shake

Re: Timing belt tensioner shake