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Thread: Astr 1.6 8v mk4 - Beginners guide to changing cambelt, checking timing?

  
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    sinbrad's Avatar
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    Astra 1.6 8v mk4 - Beginners guide to changing cambelt, checking timing?

    Ok guys, As you will see from other threads I'm having a mare trying to suss out a strange rattling noise coming from the engine. On my other post I put a link to a photo of the area where the noise is coming from? Having carried out more searches there is a 1000 and 1 different suggestions to what the noise could be. Anyway I'm gonna start at the beginning and work my way up. The first port of call is the cambelt ie timing etc. I don't have a haynes manual for the car so wondered if anyone one of you guys out there had a how to guide, a link to one or is it a case of a trip to halfrauds?

    cheers

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    This was my rough guide when i did my timing belt renewal
    If removing the timing belt it is best to renew the waterpump ,thermostat ,crankshaft pulley bolt and timing belt kit(which has the tensioner in with it) This is a rough guide for my 1.6 8v astra 2001 z16se)

    Well first off loosen drivers side front wheel and jack up the car and fit axel stands...then remove front wheel..remove spark plugs as this makes it easier to turn engine over by hand...Remove air cleaner assembly ,then remove upper timin belt cover (3 bolts on my cover)...Turn the engine over by hand using the crankshaft pulley bolt clockwise (which is an E18 torx bolt on mine )so that the timin mark on camshaft sprocket is aligned with the cut out on rear timin belt cover..and the mark on the crankshaft pulley is aligned with the mark on the lower timin belt cover..

    Just rotate the engine by hand untill all these marks align so that you have the timin on it's compression stroke which will be TDC ...Now when i did mine i did not have any timin marks on my crankpulley so i aligned my timin marks on the camshaft sproket and rear timin cover then put a long screwdriver down number 1 cylinder and rotated the crank till screwdriver moved up to it's highest point and i could feel the piston (do not use a screwdiver that is to narrow on the handle as you don't want it fallin through also be careful that you don't trap the screwdriver in there as well).

    You can check your alignment of the timin marks once the crank pulley is removed later...Remove your drive belt from the alternator and pulley by using a socket on the tensioner (which is spring loaded) and push it back towards the bulkhead so the belt is slack enough to be removed..don't let the tensioner snap back and watch your fingers lol..

    Now here is the hardest bit and was a pain for me ,removing the crankshaft pulley bolt..i tryed everything breaker bar ,someone hold foot on breaks while car was in gear and it would not move..I ended up refitting it all back and dropped by a garage who loosened the crankbolt in less than ten seconds with his air gun( if you think yours will not move take it and get it loosened then nip it up so that you can drive home then you can easily undo it and will save you alot of grief and sore knuckles..

    Remove crank bolt and crankshaft pulley noting which way you take it off (you will need a new crankshaft pulley bolt from dealers only a few quid)

    I drained my coolant once i knew crankbolt was loosened ,by turning the little tap on the right hand side of car just under the bumper...

    Now you can recheck your timing marks again if all are still in alignment then that should be fine ..remove drive belt tensioner and timin belt lower cover ...Now place a trolley jack to support the weight of the engine to remove the right hand mount attached to the body of car and cylinder block (i placed jack with some wood on under the sump to spread the load and not damage the sump)..

    I then removed the six right hand mount bolts these were torx bolts and removed bracket from car...Now to release the timin belt you have to insert a tool (i used an allen key of the right size) and put it into the hole in the tensioner and moved it clockwise to it's stop and then locked it in place with the allen key.. Keep a check that all timing marks are aligned you will see that once the crank pulley is off there will be a crankshaft sprocket that has a timin mark that should align to the oil pump housing and the camshaftsprocket will be aligned with the upper rear timing pointer..

    Make a note how the old waterpump is fitted before it's removed..

    You can relase the tension on the timing belt by loosening the waterpump bolts (mine had 3 and were an allen key fit) now to make my job easier i used a tool off ebay that made this easier to turn the pump ,rotate the pump and belt should become slack so you can take it off..

    I then released the allen key from the timing belt tensioner and then removed the tensioner ...Undo the waterpump bolts being careful not to lose them and remove water pump i also removed the crankshaft sprocket it just slid off the shaft but note the position for later fitting...NOW the timin belt rear cover needs to come off to gain access to the theremostat so you need to remove the camshaft sprocket ,i did this by removing the camshaft cover and then held the camshaft with a large spanner on the flats provided then i put a socket on the camshaft sprocket bolt and removed camshaft retaining bolt while holding camshaft with the spanner on it's flats..Remove cam sprocket noting it's removal...

    Now you can remove the timing belt rear cover once you undo the bolts holding it...I then undid the thermostat housing bolts and moved it out of the way (i did not need to remove the hose i just left it on the housing) i removed old thermostat placed new one in with it's new seal on,refitted thermostat housing and then rear timin cover ...I then refitted the new water pump and added a little grease to the seal noting where the old pump was removed and fitted the pump bolts hand tight ...Refit camshaft sprocket the same way as it was removed and tighten to right torqe , i then fitted new timing belt tensioner and locked it in the same position with the allen key as before...refitted the crankshaft sprocket noting the right way round as previously removed..Check all timing marks are still the same and not moved ...I then fitted old crankshaft bolt and tightened finger tight,fitted timin belt makin sure all slack was on the tensioner side...refit new belt around pulley and sprockets...Recheck timing marks are still ok ..If they are then remove the allen key or whatever you used to lock the tensioner in place (do not let it snap back) ...Refit the right hand mounting to the body and cylinder block..If the timing marks are ok ,slacken coolant pump bolts just enough so they still hold the waterpump and rotate pump to take up any slack on the belt so that the tensioner arm pointer is fully over against it's stop ,then tighten the coolant pump bolts..

    Rotate crankshaft using old bolt, 2 complete turns to settle the belt and recheck all timing marks are still aligned..If so slacken the coolant pump bolts so that the tensioner arm pointer is now aligned with the cut out on the backplate then tighten coolant pump bolts to the right torqe..

    Rotate crankshaft another full 2 turns and make sure all timin marks are still aligned and that the tensioner arm pointer is still alinged with the mark on the back plate ..If not you will have to re -ajust the waterpump again as above..If all is fine ,remove the old crankshaft bolt while some one stands on the footbrake and the car is in gear ...refit the lower timing belt cover then refit crankshaft pully (if there were no timing marks on your pulley now is your chance to put your own mark on there but make sure all the timing marks align first) refit new crankshaft pulley bolt and tighten to right torqe using someone pressing footbrake and car in gear while you tighten it..I then rotated the crankshaft 2 more complete turns to make sure everything still lined up and that the engine turned over easily by hand...once satisfied i refitted camshaft cover,spark plugs, upper timing belt cover ,air cleaner assembly ,road wheel,drive belt ..removed trolley jack axel stands ,lowered car to the ground ,tightened wheel bolts Then topped up the coolant and antifreeze ..

    If i have missed owt out i am sure others will chip in..This is only a rough guide to what i did for my car and i take no responsibility for anyone attempting there own repairs ..I am not a quilified mechanic but when finished my car it now runs just as good as before i took this job on.

    Good luck

  3. #3
    fdrightup
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    to undo crank timing belt sprocket bolt put car in 5th gear leave one road wheel on the ground then get a socket and put it on the castle nut on the drive shaft then get a knuckle bar on the socket then let the knuckle bar make contact with the ground then undo crank timing belt sprocket (had to do this with my astra)

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    Quote Originally Posted by fdrightup View Post
    to undo crank timing belt sprocket bolt put car in 5th gear leave one road wheel on the ground then get a socket and put it on the castle nut on the drive shaft then get a knuckle bar on the socket then let the knuckle bar make contact with the ground then undo crank timing belt sprocket (had to do this with my astra)
    Yeah i had seen a tip like that but mine just would not go ...would still try and do that though when mine needs another service as i hate the dam bolts beating me

  5. #5
    fdrightup
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    Quote Originally Posted by astra53 View Post
    Yeah i had seen a tip like that but mine just would not go ...would still try and do that though when mine needs another service as i hate the dam bolts beating me
    had to use a torque ratchet with half inch drive to undo timing belt drive sprocket nut

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    Forgot to add that while cam cover is off it's best to clear all gunk from the cover and breathers and just give the throttle body a clean near the butterfly..mines was full of gunk in the cam cover due to thermostat being stuck open ..Temp gauge works fine now new thermostat fitted and starts to open really quickly now.

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    i no this is an old post but just wondered if you no of anywere were i can get the tool to turn the water pump cheers

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