Smoke pouring out exhaust

  • #1

    Smoke pouring out exhaust

    So to start off, because of a blown headgasket I decided to rebuild and mildly port both my heads and do NA 2 Turbo conversion on my car. After what seemed like forever I finally put everything back together this weekend and the z fired up on the first crank, although it idled really rough. When it was idling there was no smoke whatsoever but once I reved it up past 1500 rpm smoke started coming out of the O2 elbow (no down pipe attached yet) and when I let it idle again it still had smoke coming out of the exhaust. At first I thought it was just the oil I used to keep the cylinders and pistons from forming rust but it still hasn't gone away and it comes out in a thick cloud like as if I was seafoaming the car and kinda stays around just like seafoaming. I was thinking it might be the turbo, but it did come off a running parts car and had zero shaft play on it and when I checked the pipe connecting it to the throttle body there was no sign of oil in it. What do you guys think could be the problem? Any ideas and advice would be much appreciated!!!
  • #2
    Always helps when you say that color the smoke is…you say it seemed like seafoaming it, so I assume white?? White would be Anti-freeze…
    - VG30DET (HE341) 86 300ZX - 1982 280ZX Turbo - Headered NA 1986 300ZX 2+2 - 2000 Xterra -
  • #3
    Sorry I forgot to mention the color, it's a white grayish smoke not a pure white like when the headgasket blew, so I wasn't thinking antifreeze. It was thick like seafoam being burnt off and and filled my drive way and eventually blew into my neighbors yard.
  • #4
    My 86 Turbo worked great until I spun a bearing, I put an n/a block in it with the orginal turbo. Now when I boost it burns oil, Hope this helps. But your problem does sound like antifreeze so I would change my oil and see if there is any antifreeze in it. Maybe your head gasket didn't seal.
  • #5
    my guess is incorrect torque procedure or unclean head/block surfaces
  • #6
    So I did some more investigating and found oil dripping out of the o2 elbow which makes me think that the turbine side of the turbo is leaking a small amount of oil. I didn't stop there though, I did a compression test on the motor after letting it run for about 5 min which is about when it heated up enough to start billowing out smoke.
    The results for 5 cranks are:
    Cyl 1: 155 psi Cyl 2: 175 psi
    Cyl 3: 153 psi Cyl 4: 172 psi
    Cyl 5: 149 psi Cyl 6: 175 psi

    I decided to do 7 cranks just to see if i could build any more pressure:
    Cyl 1: 163 psi Cyl 2: ~185 psi
    Cyl 3: 160 psi Cyl 4: ~185 psi
    Cyl 5: 153 psi Cyl 6: ~185 psi

    So my passenger side headgasket didn't seal properly like you guys said and I'm thinking oil used to lube up the cam might have came out the back onto the gasket between cyl 5 and the big oil galley???
    Anyways I was wondering if you guys had any input before I start taking things apart, and would the brand new intake gaskets have to be replaced again or would they be reusable as the engines barely run?