So as well as my Fabia, I have two Vauxhalls, an Insignia and a Vectra. Both are of the 1.8 VVT kind. I decided to teach myself how to do a timing belt change on the vectra, because you gotta start somewhere. Anyway, all was going well until I started the engine and it made a god awful racket, so as quick as I could, I stopped the engine and inspected my work. Timing was fine, but I noticed the Aux belt that I also changed hadn't moved, and sure enough I hadn't tightened the crank pulley bolt enough (used a breaker bar then tested it with a torque wrench) causing the pulley to come off its guide on the crank sprocket and sheered the guide flat. My first fear was it wrecked the timing and in turn the engine, but I inspected the belt and all the camshaft gears and it seemed to be okay.

 

So, my hope is I can remove the crankshaft sprocket and replace with new, redo the timing again, replace the pulley and get a new bolt and it will be off to the races, this time using an impact wrench I will borrow from a friend. My biggest fear is that its knackered something on the crank inside the engine, although I would like to think I didn't have the engine on for long enough.

 

What do you all think? Easy-ish fix with not much damage, or me having the engine on for probably less than 3 seconds is enough to be catastrophic?

Edited 2 September, 20241 yr by Kalum0101

Do you mean that you sheared the drive key in the crankshaft for the lower pulley?

 

If so look carefully at the keyways in both the crankshaft and the pulley, if the pulley one is damaged then replace the pulley, if the crankshaft one is damaged then the crankshaft is scrap.

 

No matter what bodges are carried out with Loctite etc or how much you tighten the pulley bolt any movement will soon amplify and shake the pulley loose again, for a drive key to work it has to be a transition fit in both the crankshaft and the driven pulley, no play whatsoever is tolerable.

So on the Vectra Z18XER engine they have the pulley (first pic) and it attaches to this crankshaft gear/sprocket (second and third pic). The pulley sits of a keyed ridge on that gear best seen in the third pic, then you tighten the crankshaft bolt down so that the pulley stays keyed with this ridge. Its this that has been sheered off so the gear is now basically flat, meaning the pulley now doesn't sit right. The gear however stayed in place the whole time, so I would like to think there is no damage to the crankshaft

 

What I am wondering is if I extract the gear from the crankshaft and replace it with a new one, then get a new pulley and a new bolt, that it should be the end of it and hopefully its not damaged something internally.

 

Sorry if I am not explaining it very well.

Edited 2 September, 20241 yr by Kalum0101

So just the protruding end of the left hand drive key has sheared off leaving the crankshaft pulley sitting concentric on the protruding part but not capable of being driven?

 

Looking at the photo it seems there is a key on the right driving the toothed drive wheel from the crank and one on the left driving the pulley, is that right?

 

If the key on the right is not damaged and especially the keyway in the crankshaft not damaged then you have dodged a bullet, a new drive wheel and possibly pulley should suffice.

 

It looks like clever design where the LH sacrificial key with limited engagement will shear if the bolt is loose but the longer key driving the toothed drive and cams which have less inertia than the harmonic damper pulley will be undamaged, as you stopped the engone quickly you have a very good chance.

Yes correct, the key on the left has been completely worn away by the pulley but the key on the right is fine. I'll get some proper photos of my drive wheel / gear / sprocket (not sure what to call it now) when I get home to show the damage done.

 

So looking good, just need to figure out how to extract the drive wheel, as there doesn't seem to be much info online about replacing it.

Edited 2 September, 20241 yr by Kalum0101

Here's a picture of my gear. Not the best angle, but you can see the worn part on the tab pointing towards the TDC, but the rest looks okay.