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Thread: Timing Belt Disaster on Vauxhall Astra 12.4 / 8 valve

  
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    Timing Belt Disaster on Vauxhall Astra 12.4 / 8 valve

    Looking for some advise and help with my 1999 Vauxhall Astra 1.4/ 8 valve.

    Background : to save money I decided to change the timingbelt myself and ended up making a real dogs dinner of the operation (Don't ask)
    I need to set up the ignition timing from scratch but aftertwo days under the motor I still haven’t got it right.


    1. I can’t get the cam sprockets to line up. When I turn the lefthand sprocket (rear) it comes almost to where it should be (opposite the mark on the righthand cam) and then clicks down to nearer 4 o’clock



    1. The Haynes manual says set it to TDC on the compression stroke. The method I’m using is putting a screw driver in the spark plug hole and as I turn the crankshaft be hand the screw driver rises to it’s highest point at which point the mark on the crank sprocket lines up with the mark on the rear lower cam cover. My problem here is how do I know No 1 piston is on the compression stroke or the exhaust stroke.



    1. There is a big heave ‘washer’ (2”wide by1/2” thick) which fell on the ground when I initially stripped the bits and I’m not sure how this goes back. I’m assuming it locks the pulley over the crank sprocket. Is that correct ??


    As said above I need to set up the timing from scratch so ifany of you guys can help I’d really appreciate it.

    Thanks in advance

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    The camshaft will try and rotate as the valve springs are trying to decompresss. Either cut a wedge peice of wood to stop it turning and use it to temporary lock the camshaft by inserting it between the camshaft pulleys or buy the locking tool.

    The crank doesnt matter providing number 1 and 4 are at TDC. Use the arrow on the crank pulley and the mark on the casing to time the crank up. It sounds like you have removed the belt without timing it correctly. Is this the case

    Im not sure about the washer but my guess is its something to do with the crank/crankbolt.

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    you say you have 8 valve astra but talk of 2 cams sprockets? thats a 16 valve engine then?
    16v locking tool is about a tenner off ebay, i used the wood wedging method as mark mentions above
    this how i 'bodged' the locking tool http://www.astraownersclub.com/vb/sh...tool-home-made
    washer sounds like it is the one on the crank pulley bolt
    Last edited by Ciano; 07-08-2013 at 17:48.

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    They dont do a 8v 1.4 astra G. My guess is its x14xe or z14xe. Both are timed the same way

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    Marks152 :
    Thanks for clearing up the point about TDC
    I’ll definitely cut a timber wedge to jam the cam sprockets.
    And, YES, I jumped in with the tools a bit too enthusiastically and had the belt off before I realised what I had done….
    So –. Line up themarks on the cam sprockets and jam them in place.
    Rotate crank until No1 piston isTDC and the mark on crank sprocket is in line with mark on lower cover.
    Refit the timing belt and released the tensioner pulley

    Is that the correct sequence.??

    Ciano :
    Yes, you’re right of course. It’s a 16 valve.
    Will make up a locking tool similar to yours if Marks152 timber wedge doesn’t get the job done for me.
    I figured that heavy washer went back on with the crankshaft bolt – there’s a raised surface on one side of it and I’m still not sure if this faces in or out.


    Appreciate both your advise. Got a day off tomorrow so hopefully I’ll be able to sort it.


    At the risk of making a pest of myself – how do I identify the exact engine type in my car. Is it stamped somewhere on the engine or elsewhere on the body.
    Last edited by murmont; 07-08-2013 at 20:35.

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    if you have the car pass it should say on there what engine code
    also i think if you have throttle cable rather than 'fly by wire' throttle it is an x14
    think crank sensors are in different locations for z and x series

    also I take it you are putting on a new belt, pulleys, tensioner and water pump?

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    You need to be very carefull moving the camshafts or the crankshaft independantly as they are now not in sync and some of the valves will always be open and if the piston come up and you carry on forcing it then you will bend the valves. if you feel the piston touch anything - STOP. Remove all plugs. Its going to be a bit of a hit and miss "game" to get the markers all lined up again. Just dont force anything. Chances are you will have to turn the crank a bit until it "just touches" the valves and then move either camshaft one way or the other to close the valve that is contacting. Go slow and you should be ok.

    If you look at the camshafts. You will see they have a mark on each pulley. Its usually a line. The have to face each other in the middle and should be level. The crankshaft has a arrow on it and should be in the 5pm position. There is a mark on the casting. So basically your just lining the marks on the crank and making sure they camshaft marks face each other and then refit the belt.

    Once fitted turn the engine over with a spanner/socket on the crank bolt at least 2 times then recheck the timing mark.

    I just really hope you aint tried to turn the crank already and bent the valves. Ive got a bad feeling in my stomach.

    As ciano says. You should also change the waterpump on this engine when doing the belt or the whole lot might be a waste of time if the pump bearings go which can often happen when a new belts fitted with a slightly different tension

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    It would be hard to bar the engine over enough to bend the valves.
    I doubt I could put enough force onto the bar once it locked up.

    As to the lining up, I did my Z18XE, and I had to put a socket on the cam shaft pulley to tweak it back to line it all up, as the valve springs just moved it forward enough to take it out of alignment.

    So line it all up, lock it in place, or move it back/forward as required, put the belt on, tension it, and bar the engine over twice.
    If you can bar it round, it's not going to cause damage. If it starts, you're right, if it doesn't, you may be 180 degrees out.
    (If you can't bar it round, try again from scratch)

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    Ive thought of a even easier way of setting the crank/cam sync without risking valves colliding too much. If you turn the crank clockwise until all pistons are level (you may need to tweak the cams one way or another to stop it hitting piston) and piston 1 and 4 are just starting to rise then adjust the camshafts to the correct position and then turn the crank clockwise until the mark lines up at 5pm position. This will then allow all the marks to line up. Fit the belt and hopefully it will start. If not then the belt needs to come back off and the crank turning a further turn whilst manipulating the camshafts around to avoid valve collision.

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    The obvious thing would be to turn the engine once the covers have been removed to make sure the marks line up BEFORE the belt is removed. I know your method is for when the timing has been lost but best to prevent it happening in the first place. Mine is due for replacement so this is helpful info.

    Do your homework first before wielding the spanners.
    2001 Astra LS 1.6 16v (Y536 ORO)
    1972 Triumph Dolomite 1850 auto (NYE 751L)
    Check out my Blog at http://triumphtoledo.blogspot.com

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