Vectra cam belt

[iain90210]

I am replacing the cam belt on my Vectra. My problem is that there is not enough slack in the belt to get it over all the sprockets and pulleys.

I am sure the tensioner is in the correct position. i.e. putting the least tension on the belt. Also that the belt routing is correct.

I have compared the new belt and replacement tensioner and idler pulleys with the old items. It all looks identical. I am using a PowerGrip kit which is correct for the Z18XE engine.

The crank and cam shafts are in the correct position.

I can almost get the belt on but it is too tight for me to slide it over the edge of the last pulley and into position. I am only doing it by hand. I have not used any tool to try to put the belt on for fear of damaging the belt or pulley.

Vectra 1.8 ecotec. 2001 model. Any help or advice appreciated.

 

[jayzee]

Are you putting belt on longest run first? Sure sprockets havent moved? Should be more than enough slack if you back off tensioner fully.Check belt first properly make sure its exactly the same size and count the teeth.

 

[iain90210]

Thanks jayzee for taking the trouble to reply. To answer your questions:

Yes.

Yes, and I think belt would go on even if sprockets have moved.

There isn't, and I have. I know what you mean though - I have always had more than enough slack before.

And finally I tried re-fitting the old belt and had the same problem. Will count the teeth though.

 

[jayzee]

Try this-put old & new belts on each thumb stretch arms out, keep thumbs straight, stretch as hard as you can, any difference will be immediately obvious.(one belt will be slacker) Once youve confirmed belt is ok,Look again at set up, problem is definitely staring you in the face!I reckon youre half a tooth out somewhere Regards J.

 

[iain90210]

Will have another look tomorrow - hope you are right and the problem will be obvious after a nights kip!

Thanks for your help jayzee - haven't you got anything better to do on a Saturday night though?

 

[jayzee]

Baby sitting . Waiting for the Khan fight. One round! Lucky punch or what.Anyway how did you establish timing marks? Regards J.

 

[jonnyfishing]

Have you changed or moved the water pump ? If you have you need to check that the pump markings are aligned with the block.(@ 12 O clock position)

 

[iain90210]

Timing marks are stamped in to the camshaft sprockets and these marks face each other at TDC.

Crankshaft sprocket has a stamped in mark which aligns with a pointer at TDC. Seems quite idiot proof

I certainly haven't moved the water pump intentionally. I am only renewing the belt and pulleys, following the procedure from a Haynes manual. It doesn't mention the pump other than to take the belt off and put the new one on the sprocket - presumably you cannot change the alignment of the pump by accident doing this?

The instructions that came with the kit mention checking the water pump alignment so I have been considering this. Although the kit covers many different models so I wasn't sure this applied. (The section of the manual I am referring to is model specific).

 

[Belle427]

some belts are tight but it should go,are you trying to slip it on the camshaft pulley(s) last as its far easier to push it over them

 

[iain90210]

I am having a nightmare. I finally persuaded the belt on, doing one of the idler pulleys last and using a bit of water to lubricate.

Did a couple of turns of the engine. Timing marks correct. Looking good.


Set the tensioner to 'New' for the new belt. Got the torque wrench and managed to round off the inside of the tensioner retaining female torx bolt.

I turned the engine over two more complete turns considering whether to leave it as is or remove the damaged bolt. ( I still have the old one).

I then noticed alot of movement on the tensioner. The movement seems excessive to me and would indicate tension is not constant throughout the belt. I have seen this before when I made a mistake by turning the tensioner the wrong way,although I am sure I didn't do that this time. I am now certain I will have to re-do the fitting/tensioning procedure.

Any suggestions on how to proceed re: the bl##dy torx bolt and/or the belt tension problem?

 

[jonnyfishing]

(I know the timing marks are on the cam shafts and crank pulley and they are idiot proof, especially if you use the locking tools)

Have you changed or moved the water pump ? If you have you need to check that the pump markings are aligned with the block.(@ 12 O clock position)

The reason I asked you this is because the previous way of adjusting the belt was to turn the position of the pump, the pumps are still the same but they have now added a tensioner that is auto once it is set,so the pump has a positional mark on it. The auto tensioner is adjusted by turning it anti-clockwise. You will see some movement on the tensioner pointer while turning the engine by hand but it should return to it's setting when you come back to the timing marks for T D C.
Tensioner bolt should be 20 Nm so if you think you have enough on it, leave it till next time. If in doubt... change it.
How did you manege to strip out the centre ? wrong size torx bit ?

 

[iain90210]

Thanks to everyone who has contributed to help me.

Jonny, to take your points in order.

Following your earlier post I had a look at the water pump sprocket and saw the timing mark on it. This is not mentioned at all in Haynes. I set it to 12 o'clock as you said. How does this sprocket tension the belt? Does it have a 'cam' movement like the tensioner roller?

I turned the tensioner ANTI-CLOCKWISE to the NEW belt position.

The pointer does return to it's setting at TDC. I am concerned that the movement seems alot (across the range on the back plate) during rotation.

I am not happy that the tensioner bolt is sufficiently torqued. I have used chemical metal adhesive to stick the torx bit into the bolt with a view to removing it tomorrow. I suspect that the bit is not of the best quality. Combined with a very shallow bolt head and perhaps not getting the bit in absolutely straight the star shape was just stripped away. It didn't take much force (less than 20Nm anyway) It was the correct size.

I bought a new set of torx bits today, allegedly professional quality. Trying the new bit in the old bolt seemed to be a much more solid fit. Of course I will be v. careful

 

[jonnyfishing]

iain90210
Autodata make reference to the water pump markings.
I think you will find that the pump drive cog is not central to the pump body, so any movement would alter the length of the belt drive.

the previous way of adjusting the belt was to turn the position of the pump,

I told you the rotation direction of the belt because I thought you meant that you were doubtful of the direction you had turned it.

tensioner the wrong way,although I am sure I didn't do that this time.

I think the timing/tension is correct. Hope you manage to extract the bolt without too much fuss i.e. " little swearing and no skinned knuckles"
p.s. my comments were only meant to be helpful.

 

[jayzee]

I think the point Johnny is refering to is have you loosened the water pump bolts /and physically moved the pump? I would recommend renewing the pump now anyway,they are prone to leaking.This will also aid you in fitting the belt,as turning pump in its housing increases/decreases the belt tension.Dont be tempted to leave old pump installed though, once you loosen bolts.

 

[iain90210]

Guys I really do appreciate you taking the time and trouble to advise me when I have posted asking for help. Jonny I have seen many of your previous posts and you clearly know what you are talking about. Certainly no offence taken. It was pretty clumsy to strip the bolt head. BTW whats wrong with hex head bolts anyway

I am going to have a go at getting that bolt out today - hopefully that adhesive does what it says on the tin! I have used it before and found it effective.

This job has been much harder than anticipated. Never had to remove engine mount bolts before but did this time to replace auxiliary drive belt (successfully - bolts back in now)

I have a new thermostat and housing to fit to the car as well. Will do this when the belt covers are back on. Did a quick pre-check to see how I would do this. Of course the bl##dy thing is attached with more bl##dy torx bolts which are almost inaccessible. I have just ordered some star ratchet spanners, wobble bars and angled torque drivers just for this bit.

Feel better to have got that off my chest.

Iain