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Fitted a new cam belt on my 2001 Astra 1.6 8v problem.

Discussion in 'Astra, Corsa, Zafira, Meriva, Adam, Agila, Tigra & Nova [Includes AstraVan & ComboVan] owners forum' started by nickjaxe, Jul 12, 2009.

  1. nickjaxe

    nickjaxe Member

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    Location:
    North Cheshire UK
    Drives:
    2001 Astra 1.6 8v for my wife...I have a old S3 Landrover.
    What a fiddly job it is putting a new cam belt on and I have not finish it yet, its on a 2001 1.6 8v Astra, Question I made a note of the timing marks before I took it all apart getting the cam drive cog mark in-line with the notch on the rear plastic cover and the crank cog marker in-line with the notch in the alloy engine cover, I found if the crank cog pointer was perfectly lined up, but the cam drive gog was about half a tooth out or still having about 4mm to go before being in line on its marker the notch in the rear upper timing cover, me thinking to myself I will get it better than that when I put it back together but no such luck,

    With the new belt on an all tensioned up I still find the cam drive gear just under half a tooth out,

    I started by fitting the new belt to the crank drive member then up to the cam drive member but the new belt would not line up to go on tight so the only way to get it tight between the 2 members was to turn the cam member just a bit, but as I say it all ends up with the cam memer being about 4mm shy of the cam marker on the rear case.

    Nick.

    I can see no way to better this any of you guys think of a way.

    Nick.
     
  2. Saltire1964

    Saltire1964 Member

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    Location:
    Luton, Rugby, Edinburgh
    If the marks are more or less where they were with the old belt & it sounds ok then I wouldn't worry about it. My 1995 1.4 8V is the same, the top mark seems to be a random - it's up here somewhere - mark.
     
  3. Broomies Mate

    Broomies Mate Are Your Buffalo Wings Spicy? VxON Club Member

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    Location:
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    As always, turn the engine BY HAND before using the starter. It's probable that the old belt has stretched slightly during service which would give a discrepancy if you had added marks yourself. Why the genuine marks arent lining up is a mystery to me.
     
  4. Delbert

    Delbert Well-Known Member

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    Perhaps like when replacing a bicycle chain, count the number of teeth and not the length. In addition to checking timing marks when replacing a timing belt, counting the number of teeth between the cam and crank timing marks on the straight belt run side of the old belt before removing and then check the count is the same on the new belt, might be helpful.
     
  5. astra1

    astra1 Active Member

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    Location:
    lancs
    When i did mine my timing marks were not even on my crankshaft pulley...What i did was to set it all up to TDC then i removed crank pulley and used the alignment mark on the crank sprocket as it had an arrow on it to align it with the oil pump housing (the belt was still on and crank bolt re inserted ...i then turned the engine over again till i got TDC and when i removed the old belt and put the new one on the camshaft sprocket was out by 1 tooth so i removed belt and re aligned the camshaft sprocket back so all aligned ..later on when i refitted crankshaft pully i put some white paint where the timing mark should have been..Aligning the timing marks is quite easy on these engines..You can turn the camshaft sprocket slightley back into alignment with the belt off so once that is aligned with the notch on the timing belt rear cover you should be ok once you refit the belt ...do as stated above and turn it over by hand if it all turns ok you should be good to go.
     
  6. Delbert

    Delbert Well-Known Member

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    Don't quite understand what you're saying. That is, the old belt is removed and upon fitting the new one the belt is one tooth out on the camshaft sprocket! Unless you've counted the belt teeth between the two sprocket timing marks on the straight run side of the old belt as I suggested in my previous reply, it seems to me that you probably mean half a tooth! i.e. a belt tooth lines up with a sprocket tooth and not between the teeth and so doesn't engage or mesh as it should do.

    If that's the case, which way does one turn the camshaft sprocket so the belt engages with the sprocket teeth, one might ask. This is where I think my idea of counting the teeth prior to removing the old belt would be useful.
     
  7. astra1

    astra1 Active Member

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    Location:
    lancs
    Well when i said 1 tooth it was between which i know what you are saying lol..to be honest you don't need to count teeth on a belt when your fitting a new belt ..It's all about setting up right with the pointers ..if thats to hard for some then they should entrust it to someone who is confident enough to do it..My only real problem i had was not having any timing marks on crank pulley but i just added white paint once i lined up the crank sproket with the cam sprocket and made sure i was at TDC then i refitted crank pulley and marked it in the right spot. [​IMG]p.s the cam sprocket had turned slightley when i was refitting new belt thats why it was out ..so i took new belt off an realigned it ..setting up the timing is easy enough when you study it.Just did not want to write a long winded post about it thats all lol.
     
  8. Delbert

    Delbert Well-Known Member

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    Well, if the belt doesn't mesh with the sprockets (half a tooth out I think you implied) when the timing marks were aligned (the essence of what I thought you were saying), which way does one turn a sprocket to enable it to mesh? That's why I suggested the tooth counting technique. But if the cause was that the cam sprocket had moved a tad as you say, then that's a different situation.

    I like your white paint technique, with me it would be white paint, photographs (little digital camera thingy is the most used item in my toolbox!), tooth counting and whatever else I could think of prior to disassembly!
     
  9. greasemonkey

    greasemonkey VXon Frontera Monkey VxON Club Member

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    Location:
    Bury St Edmunds Isuzu Land
    Drives:
    Frontera
    Hi you need to turn the top cam slightly using a spanner - then get someone to hold it - fit the belt so that when you release the top cam sprocket it actually tightens the belt on the longest run - then adjust the tensioner - turn over by hand job done
    cheers
    Steve
     
  10. Delbert

    Delbert Well-Known Member

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    I've yet to do mine, but this businees of setting things at TDC (for a conventional inline four pot) seems a tad risky should anything move. You know, should the crank or camshaft move a tad, you might have a spot of intimate contact within.

    My thought would be to set the engine a quarter turn from TDC, such that all pistons would be half way down the bores. No chance of a valve or two touching a piston then. Needless to say put your own marks (white paint) on cam and crank sprockets before disassembling so one can confirm them at the same position after fitting new belt and bits. Recheck by rotating the engine by hand as normal.
     

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