Technical DIY timing belt (cam belt)

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Technical DIY timing belt (cam belt)

shiningliao

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Hi all,

I am thinking to replace the timing belt by myself. I have many mechanic experience... However, I heard there is no TDC mark on FIAT cam sprocket. This might be a bit difficult. Anyone can confirm this?

Another thing is it might need a special tool to lock the cam at the right place. I don't have that special tool.... Is it really required?

Thanks in advance.
 
Yes you need cam lockers ..but if you know your stuff then you will know its always possible to make your own marks .. its very crucial that the belt goes back on perfectly or problems with running can occur ..and cam lockers will guarantee that this happens time and time again..
 
Stacks of info on this if you use Search but the simple answer is YES & YES :)

I have done a bit of search. Some people said there is no mark... but the manual says there is a mark on it.... (see the attached diagram from the manual)

So, I am a bit confused... anyone actually replaced the belt by himself?
 

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Fiats don't tend to have timing marks as it's done a much more accurate way

Two camshafts and a crankshaft all to get exactly in line. 40 teeth so one tooth= 9 degrees = way out. 1/2 a tooth= 4.5 degrees = still crap

It may sound complicated but you lock camshafts and crankshaft in exactly the right place mechanically and then, very importantly, you loosen and rotate the camshaft sprockets on the camshafts so the belt fits perfectly in exactly the right place. Then you lock everything back up as only then do you have everything synchronised perfectly. Many garages don't do that as you need the proper camshaft and crankshaft locking tools. The car comes out running like a dog with 3 legs. It has to go back or taken to someone who then does the job properly. Big waste of time.

After 5 years the belt will have stretched quite a bit so it's not good lining it up with the way it is now

It's the one chance to get everything lined back up the way it should be

Mine had a horrid flat spot from when i'd bought it that was instantly cured by lining everything up again with a cam belt change using the correct tools. It's really not very expensive a job to have someone do the job properly with the correct tools as it doesn't take very long

Change the air con belt if you have a separate one like the 1.6 has as it's a stretch fit and it doesn't stretch any more after 5 years use
 
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Fiats don't tend to have timing marks as it's done a much more accurate way

Two camshafts and a crankshaft all to get exactly in line. 40 teeth so one tooth= 9 degrees = way out. 1/2 a tooth= 4.5 degrees = still crap

It may sound complicated but you lock camshafts and crankshaft in exactly the right place mechanically and then, very importantly, you loosen and rotate the camshaft sprockets on the camshafts so the belt fits perfectly in exactly the right place. Then you lock everything back up as only then do you have everything synchronised perfectly. Many garages don't do that as you need the proper camshaft and crankshaft locking tools. The car comes out running like a dog with 3 legs. It has to go back or taken to someone who then does the job properly. Big waste of time.

After 5 years the belt will have stretched quite a bit so it's not good lining it up with the way it is now

It's the one chance to get everything lined back up the way it should be

Mine had a horrid flat spot from when i'd bought it that was instantly cured by lining everything up again with a cam belt change using the correct tools. It's really not very expensive a job to have someone do the job properly with the correct tools as it doesn't take very long

Change the air con belt if you have a separate one like the 1.6 has as it's a stretch fit and it doesn't stretch any more after 5 years use

Thank you so much for the explanation. I can see it is lots of benefit to use locking tools to lock camshaft and cranshaft so that the timing precision is readjust to the best.

Now, this worries me even if I put my Stilo into the garage. It's difficult to know if they have done the job properly or just the old fashion way which doesn't use any lock tools.

Mine is 1.9 JTD. I found it's same engine as Alfa Romeo 147 JTD. Here is a link to help people to repalce the timing belt by themselves.

http://www.alfaworkshop.co.uk/alfa_jtd_cambelt.shtml

It is clearly that they don't use any lock tools at here....
 
Ha! Thought you had a 1.6:)

Scrub all that. JTD has timing marks :D

I got it! Cheers,

Check the 1.6 manual. It is different from 1.9 JTD. 1.6 requires the camshaft lock tool as shown in the attached diagram.
 

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Yes or a Fiat specialist. The 1.2 needs special cam alignment tools too. Cheapest of the bunch to replace though for parts. I'd recommend changing the water pump and aux drive belt at the same time on the 1.2
 
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