smoke coming out of tailpipes.

Discussion in 'Troubleshooting & Diagnosis' started by TDPalmer, Jan 25, 2013.

  1. TDPalmer

    TDPalmer Veteran Member Lifetime Gold Member

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    Apr 25, 2011
    Cave City, Arkansas
    After a new carb it still did not fix the smoking problem, it doesn't do it as bad but its still there. It runs 10x better now though, the old carb had maybe 1 hole in the needle and seat and about 1lb of dirt in the floats. I'm going to put some of that stp smoke treatment in it and just drive it for a while since I think it's the rings.
     
  2. TDPalmer

    TDPalmer Veteran Member Lifetime Gold Member

    823
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    Apr 25, 2011
    Cave City, Arkansas
    I hooked a vacuum gauge to it and I could not get it up to 20hg vacuum. I couldn't even get it above 15hg it stayed between 10 and 15 and never steady, but would steady with the throttle. I broke out my Chiltons book and it said the causes of a non steady needle could be the carb or intake not sealing properly, I sprayed carb cleaner all around the carb gasket and intake gasket with no drops in rpm or vacuum ever. Another cause the book said could be a leaky cylinder head gasket or worn valve stem guides, which could also be the cause of my smoking problem. I did not have a compression tester so I took it to a mechanic shop who ran a compression test on it and he said everything checked out fine on the test. Does anyone have any ideas what could be causing my low vacuum and smoking problem? I've been driving the car all week and it has not burned any oil, and it only really smokes while it is idling and when it does smoke it's like a freight train.

    Here is a video of the vacuum gauge at idle:
    [youtube]HFZLkgOcvcw[/youtube]
     
  3. zekefreak

    zekefreak Veteran Member Lifetime Gold Member

    1,532
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    Apr 16, 2006
    western PA
    How does the pcv valve look, is it very oily? Pull it out of the valve cover while its idling, don't disconnect it and see if the smoking stops.
     
  4. daddio4048

    daddio4048 Veteran Member

    815
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    Jan 21, 2013
    Valdosta,Ga.
    It may be that whoever rebuilt the motor may have honed out a wore out block & installed new rings which over time the rings collapse a little & start letting oil blow by.With low vacuum like your seeing; it is very common with not good ring seating in the cylinder.
     
  5. TDPalmer

    TDPalmer Veteran Member Lifetime Gold Member

    823
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    Apr 25, 2011
    Cave City, Arkansas

    I replaced the pcv and the hose, the old pcv was not oily at all. I'll pull it tomorrow and see if the smoking stops.


    That could be the case too, the engine has a steel plate on it that says rebuilt, kind of like what autozone puts on their engines.
     
  6. TDPalmer

    TDPalmer Veteran Member Lifetime Gold Member

    823
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    Apr 25, 2011
    Cave City, Arkansas
    I took the pcv valve out and it didn't change the smoke any, I drove it around town about 30 minutes today and when I got home the smoke looks white now. I just can't tell what color it is and it's driving me crazy. I've drove the car all week, all day yesterday and 30 minutes today, about 200 miles and it hasn't used any coolant or oil at all. I'll check my oil after it cools down to see if it looks milky.

    Here's a short video of the car after 30 minutes of driving, my girlfriend thinks it looks more white than before now too. The temp is 63 degrees outside and there was no water coming out of the pipes when this was recorded.

    [youtube]trDZsiO2Rac[/youtube]
     
  7. My 76 smoked like that when it was a 350. Never really solved that till i had steve kanuika build me a 400.I always blamed teflon valve seals. Just kept pumping oil in.:screwup:
     
  8. Knuckle Dragger

    Knuckle Dragger Moderator Staff Member Lifetime Gold Member

    12,838
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    Nov 2, 2002
    Waddell AZ
    The first video looked like condensation to me. You could see droplets of water coming out of the bottom of the pipe. Second was definitely blue :( How many miles on the engine, and chance the rings haven't seated yet?
     
  9. TDPalmer

    TDPalmer Veteran Member Lifetime Gold Member

    823
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    Apr 25, 2011
    Cave City, Arkansas
    I'm not quite sure how many miles or how old the rebuild on the engine is. It's just got a rebuilt stamp with a serial number on it, when I put the cam in everything looked new that I took off. I've had the engine two years and it never smoked until recently, the engine never got hot and my oil psi has not dropped. I've taken off my cutout plates that dump right at the headers and I could not feel any oil on the pipes or on the block off plate.

    I've been staring at a bottle of Rislone Ring Seal & Smoke Repair on my computer desk but I can't bring myself to pour it in my engine cause I've heard it can coat the cylinders in gunk that won't come off.
     
  10. Knuckle Dragger

    Knuckle Dragger Moderator Staff Member Lifetime Gold Member

    12,838
    197
    Nov 2, 2002
    Waddell AZ
    I wouldn't use that stuff. Have you checked to make sure the PCV system is working? Checked the compression? I doubt seriously the rings went south at the same time you replaced the cam. If it wasn't smoking before I'd look else where. Lots of good suggestions in this thread.
     

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