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Z12xe head on a x12xe block?

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  • [Corsa B 1993-2000] Z12xe head on a x12xe block?

    Hi all, I've been scouring images of rocker covers all night and I'm fairly sure I have a z12xe head on a x12xe block. First clue was the rocker cover gasket in the head kit didn't match!
    As some of you know, i 'be had a number of issues with this motor and as I'm new to vauxhalls, I didn't know any better!

    I've also swapped the ECU etc over with what I thought was a x12xe so I'm sure that's not helped if its a z12xe head.

    Swapped it back to original (one that was on when I brought car) so if its been mixed, it should be OK now.

    My questions are these!

    Is it possible to have a z12xe head on the x12xe block?
    - the throttle body, inlet manifold is cabled x12xe.


    If it is a mixed engine, what timing cover gasket do I go for?

  • #2
    The timing cover for the x series and z series are the same, but the inlet ports are different, specifically the EGR porting - and the EGR gasket for the x12 and the Z12 is different due to the different ports.


    1972 Viva restoration thread -


    • #3
      That's good info. I've taken a PIC for id purposes, note the cabled throttle and the rocker cover shape/bolt positions. I've looked at loads of images and can find none that have these bearing in mind its a corsa b 2000 and 1.2 16v on log book!
      Can anyone ID this for me please!


      • #4
        That's a Z12XE head.

        There was a query on another site (which shall remain nameless) about this. The thing to remember is that the Z series engine ECU is different to the X series in several ways - eg how the cooling fan is controlled, there is no separate coolant temp. sensor on the EGR valve, it uses the CTS for both funtions.

        SO check your EGR valves, see if it's running a coolant temp. sender on it or not. (Can't see clearly on the photo.) If it doesn't then your ECU will be running the Z series options. If it does then it's more likely to be a X series ECU.
        Last edited by Taurus; 12-07-2014, 11:50 AM.
        1972 Viva restoration thread -


        • #5
          Thanks again mate. So this explains all my recent woes. How would you suggest I proceed?
          I think its been mucked around too much and all sensors etc are confused. Do I fit a x12 head or can I carry on with this?
          I'm very tidy when it comes to these things as I like them to be as they were engineered to be grr.


          • #6
            Here is the egr valve pics


            • #7
              That's got the water temperature sensor on the EGR valve, so it's running the X series engine management. I assume they've fitted the x series inlet manifold to the z series head, which is fine. Just treat it as a X12XE, with the exception of cam cover gasket.
              1972 Viva restoration thread -


              • #8
                Great news. Thanks once again mate.