Cambelt change/Crankshaft pulley nut help!

Hey everyone!
Does anyone have a pearl of wisdom they can give me because I'm getting really frustrated!
Started a cambelt (and also an auxilary belt) change today as I have a week off work.
Started out okay but I just can't seem to crack off the crank pulley nut.
I guess in the garage it would be off in seconds using a compressed air gun but it looks like I need to lock the pulley in place so it won't turn.
I've soaked in WD40 but it still won't budge and just turns the pulley.
Seems impossible to crack off the nut without loosing the timing mark alignments but I guess they can be re-aligned again after as the pulley has a keyway on the crank?
Desperate for any help on how to lock the pulley.
Gaz.

Hi Gareth,
Are you just replacing the cambelt and alternator belt?
If so, there shouldn't be any need to the remove the crankshaft pulley.
You can replace the belt by loosening the cambelt tensioner. This should just about give it enough play to slide the belt off.
It's a tight fit getting the new one to slide on but can be done with a bit of patience.
It is also worth replacing the tensioner while you're doing the job as well.

Cheers
Andy

Hi Andy......have I been accidentally thick here?
I am indeed replacing the alternator belt also.....and I have a brand new tensioner pulley.
The cambelt has been slackened off on the tensioner and slipped off.
So, I guess you're saying that I remove the alternator belt first that will then allow me remove the cambelt over the crankshaft pulley.
I can't believe I've been such a wally!
All of the guides I've read all say to remove the crankshaft pulley!.......

Hi All,
Just to close out this thread and give you an update.
Andy.....thankyou so much for sharing your knowledge. I removed the alternator belt first as I was going to replace that anyway.
I then removed the cambelt by twisting it slightly and sliding it out between the gap in the crank pulley and the timing mark bracket.
No need to remove the crankshaft pulley although it is fiddly as you can't see the toothed pulley behind it.
So yes, it can be done without removing the crankshaft pulley nut.

Gaz.

Hi Gareth,
Glad you've managed to get the belt off OK. I forgot to mention that you can cut the belt off if necessary.
Also, yes, the alternator belt needs to be removed first. and refitted after. The alternator belt can be a tight fit as well!

Cheers
Andy

Hi Andy.....yes, the alternator belt was very tight. I slackened off the alternator bolts but it would only move a small amount as it was hitting the crank case.
I ended up having to remove the bottom throughbolt as if I was going to replace the alternator to get it off!

Gaz.

That's what I normally do, take the alternator off complete, fit the belt to the pulley and then wrestle back in position.

Andy.....the only thing I couldn't do was replace the cambelt tensioner.
All I had was the roller and I didn't know that when I took it off, it was mounted on the bracket.
It looked like it was put on using a hydraulic press which I don't have so I oiled it up and put it back on.

Gaz.