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Compreesion test

Discussion in 'Forced Induction' started by smooth_criminal, Apr 18, 2005.

  1. smooth_criminal

    smooth_criminal Senior Member

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    Well i took the day off of work so i could figrue out what was going on with my car. Well i did a compression test and heres the results.

    Cyl 1. 190
    cyl 2. 70
    Cyl 3. 180
    Cyl 4. 195

    So this means my rings are shot right? So now it's time to buy new pistons and rings right? Let me know what brand / model i should go with. I should buy rods while i'm at it.

    I'm looking for a daily driver with 250 Whp.
    B18b1
    18g greddy kit
     
  2. reckedracing

    reckedracing TTIWWOP VIP

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    is it already running the turbo or not yet?

    the low compression could be 3 possible things...

    1. is your rings
    2. is your valves
    and 3. is your head gasket...

    the easiest way to check is to put the motor at TDC and do a leakdown test, which basically means just putting air into the combustion chamber to pressurize it...

    the pressurized air will be leaking from somewhere...
    you wanna take the oil filler cap off, if the ait is coming out of there then its your rings... if the air is coming out of the intake then its your intake valves, and the same for the exhaust...

    if you don't see anything from these three locations then it could possibly be your headgasket, then you wanna check your oil for any coolant and vice versa...

    are you sure you got a good reading on cyl #2?
    thats a really huge diffrence, and i;m guessing that there is a problem that caused it... if you are already boosted i would seriously look into your fuel supply before running this motor again...

    edit: and if it is rings you're prob gonna want more than just pistons and rings... like rebuilding the whole bottom end, bored, honed, possibly sleeved but not necessary for 250whp...
    def get the cylinders checked out by someone who builds engines...
     
  3. reckedracing

    reckedracing TTIWWOP VIP

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    what were the symptoms that lead to the comp test?
     
  4. smooth_criminal

    smooth_criminal Senior Member

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    Yeah it's already boosted. And your right i'm when i tyook the plugs out there were all white. I tested number 2 , 3 times so i'm thinking it was a good reading.
    As for fuel i'm running rc310 injectors with a blue box. (I know shittly)
     
  5. smooth_criminal

    smooth_criminal Senior Member

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  6. reckedracing

    reckedracing TTIWWOP VIP

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    damn

    thats sucks dude...

    thats sucks real bad...

    sounds to me like you rocked that motor...
    damn, that fucking sucks...

    did you get the injectors new?
    did plug from cyl #2 look any diffrent from the rest?
    you can try putting oil in the cylinder and doing another compression test... if it blows higher then its most likely your rings... oil helps boost the compression psi...

    hopefully you just burned a couple valves or something...
    that would be a lot cheaper than going into the bottom end...
     
  7. reckedracing

    reckedracing TTIWWOP VIP

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    what codes are you throwing?
    do you have an upgraded intank fuel pump?

    what do you mean by misfiring?

    how long did you run it with the blue box and shit?
    did you know the compression of the motor before you put the turbo on it?

    did you just buy this car? or was that someone else?
     
  8. pissedoffsol

    pissedoffsol RETIRED

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    don't order shit until you rip it apart.

    ordering new pistons when you have a cracked sleeve isn't going to get you anywhere...
     
  9. smooth_criminal

    smooth_criminal Senior Member

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    1, Codes 71 , 73 and 74
    2, No
    4, I'm not 100% sure thats what the codes read mis firing in cyl 1 , 3 and 4. I'm guessing they mean detonation

    5, About 3 weeks
    6, Nope
    7, I've had this car for about 3 year, Just swapped the motor in 2 months ago everythign was running 100% Put the turbo on like 2 / 3 weeks ago.
     
  10. smooth_criminal

    smooth_criminal Senior Member

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    Just did this and the read was 150 so it jumped up does that mean it's my bottom and not the head right.
     
  11. reckedracing

    reckedracing TTIWWOP VIP

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    sounds like its not a valve issue...

    ok, have you warmed the motor up to normal operating temp and then pulled a comp test?

    be careful, it will be hot
    lol
     
  12. smooth_criminal

    smooth_criminal Senior Member

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    No not yet, I've going to go running for like an hours. I'll do the test when i get back..
     
  13. GSRCRXsi

    GSRCRXsi Super Moderator Moderator VIP

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    yea sounds like rings to me if oil in the cylinder bumped it up that much
     
  14. smooth_criminal

    smooth_criminal Senior Member

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    OK i warned the car up and jammed the throttle wide open. Readings are as follows.

    1. 190
    2. 90
    3. 195
    4. 205
     
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