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Thread: Need help with timing

  1. #1
    Join Date
    Sep 2014

    Default Need help with timing

    Hi everyone , I have the vauxhall Astra G 1700 dt year 1999 with the GM engine, I got to renew the cambelt and head gasket, so I started with lining the marks up for doing cambelt by hand and the belt jump anywhere up to 6 or more teeth,
    lining the marks up, can see where to line up the bottom pully and fuel pump but can't see where to line up the OHC pully, can see two marks on the pully but no marks where to line it up with
    can anyone help me please

  2. #2
    Join Date
    May 2008


    There are no marks for lining it up. Usually before stripping it down a mark is made on one of the camshaft caps and one on the camshaft itself. If you have not done this then you will need a dial gauge to set up the cam lobes to accurately set the timing.
    You may get it near enough by ensuring the crankshaft is set 90 degrees before top dead centre i.e. the small cut out on the crank pulley is at 3 o'clock exactly. The exhaust cam lobe for number one cylinder must be pointing vertically upwards.
    Ensure you turn the engine at least 2 full revolutions by hand to check that the pistons and valves do not collide.
    The timing for the pump may be out and it may not start without the use of the dial gauge and the whole process of setting the timing.

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