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Thread: compression figures?

  
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    Glasgow_Stu's Avatar
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    compression figures?

    done a quick search but cant find much..

    have had a few issues with the coupe lately and its looking like stem seals or piston rings.

    a few test have been done and although it looks like stem seals the tests dont show anything up..

    compression figures are: C1=120, C2=115, C3=110 and C4=120

    now i know C2 and C3 can suffer from heat due to turbo etc..

    but what should i be hitting? Could this be that the rings are going and thats causing the smoke?
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    The z20`s ive tested usually make between 145-160 psi per cylinder for a healthy engine, my current engine makes 185psi exactly across all 4 cylinders @ 8.7:1 comp ratio.

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    so going by this could it be my piston rings that are going then?

    anyone that was at the joint meet a few weeks ago will know how bad the smoke was... ITs deff not the turbo tho.. only happens on idle and hard boost ... and its not oas or anything.. just when at lights and pulling away its bad then clears..

    idealy i wanted this fixed for PVS as its a hell o a drive there and back plus my normal miles a do at the weekends..

    thing is im running 260BHP on standard intercooler etc and block has done 87k so im thinking its poss time to have them changed before any damage is done..

    New intercooler is hear just need a fitting guide now as i just cant get my head round the turbo side o things...
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    but the sounds of it i would pull the head off and get the valve stems done while its off and see what there is to see with the pistons and rings while its off as if they are coming out then the engine is half stripped down anyway.

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    did you take all the plugs out when you did the test. what year is your coupe as later z20let engines had the pistons changed to lower compression ones. it could be 1 of 3 things
    rings
    head gasket
    valve stem seals

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    You want an extra hand or head to help fit the intercooler Stu?
    Scottish Member? Have a peep at our Region For tints or wraps Click Here!!

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    I would hazzard a guess at the valve stem seals, My last car had that prob when it first started up then sitting ticking over or stopped at the lights it would reak everyone out the smoke was blue, I replaced the seals and had no probs managed to change them my self in an afternoon, My pals Gsi has started to do this also. If you take off the head to change the seals, Get a jug of petrol measure an amount out and pour the same ammount in to each piston cylinder if all the petrol drains past the rings really quickly the rings are shot if the petrol stays for a lot longer then there fine, I was shown this by a mechanic friend of mine when i had bother with my piston an rings on one of my old cars.

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    my very close friend zafgsi is my mechanic

    he done the tests at his work. we are going to check his compression on the bus to compair against mine as cant seem to find the figures vauxhall give out.

    it do sound like the seals BUT when he done the test ( some mad shit with a smoke machine lol ) its came up with **** all..

    Dave yes please! I am really struggling! lol... I aint around this weekend.... next weekend is the im clarke rally so wont be around then either! and PVS is 2 weeks after that.

    gimme a text sometime buddy
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    Mine was smoking like a chimney when it went for its emmision test for the mot and it passed with flying colours even though you couldn see the car for the blue smoke, Good luck with the cmpresion figures hope its good news with it.

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    lol ur telling me!

    i really want it fixed for PVS but i cant see it.. NOTHING has gone to plan... back bumper never got finished, front has a massive crack in it, intercooler not fitted, interior minging, alloys half done.. the list is endless!
    The coupe...ITS ALIVE & back from the dead....again!
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