Technical Timing Belt tension

[Desmo]

Prior to changing the cambelt at 40,000 miles I bought myself a Haynes manual. I'm seriously pissed off to find out that Haynes do not provide a specification for the timing belt tension. The best they can offer is "set it so that the longest run can only be twisted through 45 degrees but get it checked by a Fiat dealer"

Does anyone have a spec for the cam belt tension? I realise that I may have to get hold of a special tool do do it but I'm buggered if I'm taking it to any dealer.[!]

 

[Evil-Punto]

Thats not even something i'd f**k with. You do know what happens if they break or come off because of poor fitment. Go to a local garage but defo not FIAT.

 

[Desmo]

That's something I have to take issue with. I'm well aware of what happens if the belt breaks and I also know the importance of it being correctly tensioned.
I've been replacing cam belts on Ducati motorcycles for a number of years and they have 2 of them and a lot more potential for mechanical mayhem. I have also replaced cam belts on other cars with no problems.
What annoys me is that the user is is not given the information required to tension the belt on the basis that he wouldn't or couldn't do it any way. Well some of can and will find a way to do it right. I have never paid a dealer or garage to carry out mechanical work that I can do just as well if not better myself and I don't intend to start now with something a simple as a cambelt.

 

[Evil-Punto]

Chill out Bod, phone a dealer and ask.

 

[HP]

If you're familiar with cam belts, just use your best judgement. Haynes manual is prob'ly about right.

Pete.
Cinq sporting 1242cc
http://mysite.freeserve.com/close_to_cracking_up/
http://autos.groups.yahoo.com/group/Cinqs_and_Seis/
http://www.clubcento.co.uk/

 

[Desmo]

That's what I' intend to do Pete. I'll measure the tension of the old one before changing it and aim for that as a minimum figure.

Derek

 

[John H]

I'm not sure which engine your Punto has in it, but I changed a belt on a small FIRE engine a couple of years ago (Panda 999).
It's fairly easy to over-tension the belt.
The place I had it MOT'd shortly after knew just by the sound it made it was too tight :I
I slackened it off - there's quite a bit of latitude to get the 1/4 turn depending on how hard you try - the water pump bearings will now last longer

FWIW on the smaller FIRE if you break the belt there is _no_ damage [:0]
As it is a "non-interference" design: valves and pistons don't hit.