Just changed my cambelt, a few observations.. - Alfa Romeo Forum
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(Post Link) post #1 of 11 Old 05-09-07 Thread Starter
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Just changed my cambelt, a few observations..

I have just managed to sucessfully complete the cambelt and variator change on my latest 156 and have a few observations..

Compared to my 145 QV the access to some of tensioner retaining bolts is quite limited, I would have thought there was more space...

I also noticed that whoever changed the belt last did not get the cam timing spot on. Maybe they didn't use cam locks. The timing was around 15º too far advanced on the inlet although the exhaust was correct.

The belts did look quite new, although the tensioners looked to be past their best. There was also not much tension in the balance shaft belt. I am wondering whether the belts were done but not the tensioners..

The balance shafts were not correctly aligned. The front one was around 25º Out in the anti clockwise direction.

It just goes to show how many people think they know how to look after Alfas, and even if the belt has been done it may not have been done correctly.

When I get hold of the service history, hopefully I will be able to find out who did the belt last. It may even be an Alfa main dealer...

Simon.

Giulietta 2.0JTDm (170), BMW 335i Cabrio
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Re: Just changed my cambelt, a few observations..

Has it made a significant difference to the running?
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Re: Just changed my cambelt, a few observations..

It seems to pull a lot better through the rev range, before it just seemed to be holding back until around 3000rpm. It was almost as if the MAF was faulty.

Now it goes really well. I actually think it is quicker than my 145 QV was.
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Re: Just changed my cambelt, a few observations..

Interesting. My 3 litre V6 was running very rough, but seemed better at the top end, turned out the belt had jumped a tooth or two on the inlet cam. sounds similar to what's happened to yours, but I didn't think the twinnies ran at all on incorrect timing. You learn something every day!
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Re: Just changed my cambelt, a few observations..

Its not as uncommon as you might think to find belts out of timing, and balance shafts belts incorrectly set. There have even been proven examples having come from the factory with the balance shaft belt wrongly set.

Just another reason why I hate cambelts with a vengeance

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Re: Just changed my cambelt, a few observations..

i prefer a timing chain, its much easier to sleep at night.
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Re: Just changed my cambelt, a few observations..

Quote:
Originally Posted by jug View Post
i prefer a timing chain, its much easier to sleep at night.

They do still snap though, but at least you get some warning...
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Re: Just changed my cambelt, a few observations..

In the middle of changing the cambelt to my car.

The cambelt is very fiddly to tension properly, as on observation; when the catch is pushed up into the pin, and the tensioner bolt is tightened, it relaxes to near enough the same point, and the belt is only incrementally tighter?

Its the same with the balance belt tensioner.

Can anyone give me any tips on how to tension these belts properly?
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Re: Just changed my cambelt, a few observations..

I used the correct tensioner tools and tightened up the bolts with them in place. Don't forget to rotate engine forwards two turns before re-tensioning. Don't expect the yellow marks to line up when you've rotated the engine. Have someone to keep an eye on the dial gauge whilst you torque up and allow inlet cam wheel bolts some slack before nipping them up.
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(Post Link) post #10 of 11 Old 31-12-07 Thread Starter
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Re: Just changed my cambelt, a few observations..

I actually used a large screwdriver to move the tensioner into position. You have to be careful though as you will be levering against the fixed tensioner and you don't want to damage it. When you have levered it over tighten it, then turn the engine over by hand hand check the marks align. After doing this I removed the cam blocks and refitted the cam cover and coils so that I could start the car. I then made sure the pointer hovered over the hole.

I also tensioned the balance belt with a screwdriver levering it at the rear, although you will need to bend a 10mm spanner into a swan neck shape to tighten the nut up.
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Re: Just changed my cambelt, a few observations..

aaah thank you guys, that makes alot more sense as before we were forgetting to turn the engine over twice.

Im still waiting for my bloody service manual CD from Ebay, but its taking its time! I wish they did a Haynes for the Alfa's!
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