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Projects 1956 Cadillac engine smoking

Discussion in 'The Hokey Ass Message Board' started by 56cadillackid, Jul 7, 2019.

  1. 56cadillackid
    Joined: Dec 23, 2016
    Posts: 94

    56cadillackid
    Member
    from new york

    I recently got my 56 cadillac back from the shop and they told me the engine was smoking a little. I didnt really think much of it as it often smokes a little when it starts then goes away but after driving it around for a few days the smoke has gotten really bad from the passenger side exhaust and from the crank case vent. I asume that it isnt makeing compression in one or more cylinders on that side and its causing smoke to leak into the crank case but I'm not the most experienced with cars so if anyone has ideas of what it is I'm open to it. It was in the shop cause after I rebuilt the carburetor it wouldnt run for more than 30 seconds and very badly I thought I did the carb wrong but they said it looked like 3 of the spark plugs had been dropped which I thought was strange cause I really dont think I did could this have anything to do with the smoke? Again if any of this seems stupid it's my first car and I dont know much about working on engines. Here are some pictures of the smoke from driving a few minutes ago. These pictures are at idle except for the one out the back window, the smoke is worse when driving. 20190707_185755.jpeg 20190707_190404.jpeg 20190707_190418.jpeg 20190707_190428.jpeg 20190707_190825.jpeg

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  2. Moriarity
    Joined: Apr 11, 2001
    Posts: 14,707

    Moriarity
    SUPER MODERATOR
    Staff Member

    you need to do a compression test on the engine.
     
  3. Hnstray
    Joined: Aug 23, 2009
    Posts: 10,526

    Hnstray
    ALLIANCE MEMBER
    from Quincy, IL

    @56cadillackid ......What color is the smoke? Looks grayish in the pics, but that is not reliable on computer screens. If it is white or light gray, it could a coolant leak into the combustion chamber. If you are running ethylene glycol antifreeze, the smoke would likely have a 'sweet' smell to it.

    If the smoke has a blue coloration it is most likely engine oil. I don;t know if those old HydraMatics had a vacuum connection to the engine, as do many later mode;s, but if so, trans fluid could be getting into the intake system. These are just possibilities to look into. The compression test recommended is a greta place to start with your trouble shooting.

    If compression is low on most of the cylinders it is likely due to long term wear. The important thing there is how much variation between cylinders overall. If you have low(er) compression on two adjacent cylinders, that is an indication of a blown head gasket.

    Ray
     
  4. 56cadillackid
    Joined: Dec 23, 2016
    Posts: 94

    56cadillackid
    Member
    from new york

    The smoke is a grayish blue which makes me think its oil the smoke is coming out of one side so hopefully it's only one cylinder. I'm ordering a compression tester hopefully I'll be able to test it soon. What should I do if it is the compression that's messed up?

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  5. Moriarity
    Joined: Apr 11, 2001
    Posts: 14,707

    Moriarity
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  6. 61Cruiser
    Joined: Dec 5, 2013
    Posts: 72

    61Cruiser
    Member

    From the strange but true file. If all your cylinders have good or even compression but still seem to burn oil, remember this. When my father still drove my 61 Belair he had the engine reconditioned because it was blowing smoke and burning oil. The strange this was all the plugs were clean. Anyway engine gets a reco,car comes home still smoking and using oil. Rebuilder says the rings need to bed in. Dad drives this car every where for the next 4 weeks with no improvement, possibly even getting worse. The end of all this was someone suggesting pulling off the inlet manifold and see if the was a dud inlet gasket. Nope. It was the metal plate that covers the “hot box” that heats the carb. It was corroded and the oil mist in the valley was being drawn it and going straight out the exhaust. Hope this helps.


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  7. Hnstray
    Joined: Aug 23, 2009
    Posts: 10,526

    Hnstray
    ALLIANCE MEMBER
    from Quincy, IL

    Compression is lost through worn piston rings and/or valve wear. Or, as mentioned above, head gasket leaking or failure. What you 'should do' will depend on what is found to be the problem and what resources you have available or are willing to commit to repair or replace the engine. The first step is determining the problem.

    Ray
     
    Last edited: Jul 7, 2019
  8. 56cadillackid
    Joined: Dec 23, 2016
    Posts: 94

    56cadillackid
    Member
    from new york

  9. 56cadillackid
    Joined: Dec 23, 2016
    Posts: 94

    56cadillackid
    Member
    from new york

    Thanks hopefully the compression test will help me identify the problem.

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  10. 56cadillackid
    Joined: Dec 23, 2016
    Posts: 94

    56cadillackid
    Member
    from new york

    So I did a compression test on the passenger side of the engine and it doesnt look good one of the cylinders had a reading of just 0 which didnt make sense or seem right but I re did it and took the tester off and tried again and it showed the same two of the cylinders were alright with 95 and 110 psi and another was 60 psi. The spark plug for the cylinder that was 0 was covered in oil and it's only been in the car for maybe 10-15 miles 20190713_170505.jpeg

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  11. Hnstray
    Joined: Aug 23, 2009
    Posts: 10,526

    Hnstray
    ALLIANCE MEMBER
    from Quincy, IL

    May as well do the driver side compression test too while you are at it. If that side checks out at respectable pressures, and within 10 to 15 lbs of each other.....or they are wonky too, that would be good to know. If left side is good, sounds like the intake manifold and right head need to come off for initial inspection to see why 0 comp on one cylinder. If left side also is low and/or uneven it will be decision time.....rebuild or replace or sell.
     
    Last edited: Jul 14, 2019
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  12. RichFox
    Joined: Dec 3, 2006
    Posts: 9,693

    RichFox
    ALLIANCE MEMBER

    The oil and compression reading would seem to indicate a serious problem with that piston/cylinder. You could do a leak down test (Google it) But I doubt you have or want the equipment to do that. You can try some mechanic in a can to see if that helps. What have you got to loose? Otherwise it looks like the engine may need to be removed and rebuilt. $$$$
     
  13. Rickybop
    Joined: May 23, 2008
    Posts: 5,591

    Rickybop
    Member
    from Michigan

    My advice...

    Since your experience is quite limited, get some local help. Someone who's willing to look at the engine, make some determinations and give you some good advice.

    And... quit biting your nails.

    Good luck with your Cadillac!

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  14. firstinsteele
    Joined: Jun 13, 2013
    Posts: 998

    firstinsteele
    Member

     
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  15. Kid, I had the same problem with my 56 Buick station wagon. I did a compression test and found out 2 cylinder were very low so I swapped out motors. GOOD LUCK with yours. Bruce. HPIM2179.JPG
     
  16. belair
    Joined: Jul 10, 2006
    Posts: 8,020

    belair
    Member

    And be sure to get help from some one who has experience with and appreciates old Cadillac engines.
     
  17. If you have excessive blow by vapor coming from the oil fill and road draft that indicates there is excessive compression excapeing past the rings and pistons into the crankcase, If you keep driving you could damage the engine. You likely have a big problem on the dead cyl. Possibly Broken Piston rings & or ring lands. Or a Burnt or cracked piston or excessive wear. If you cannot tear it down and fix it yourself and don't have the money to pay someone else to fix it. don't take it apart. just park it until you have the money . or sell it.
     
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  18. low budget
    Joined: Nov 15, 2006
    Posts: 5,283

    low budget
    Member
    from Central Ky

    You said you redid the the test and got a good reading on the one that was zero?
    Maybe a sparkplug non fouler would help?
     
  19. I read the post My understanding was that one cyl had 95 another110 and a third one 60 and the oil covered one still has zero.
     
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  20. sunbeam
    Joined: Oct 22, 2010
    Posts: 4,147

    sunbeam
    Member

    A spark plug non fouler mite keep a cylinder running but will not help with smoking. How much oil is being used?
     
    Last edited: Jul 14, 2019
  21. If you have Zero compression not even a spark plug non fouler will make that cyl fire.
     
  22. low budget
    Joined: Nov 15, 2006
    Posts: 5,283

    low budget
    Member
    from Central Ky

    Think you are rite after looking back, I think he meant to use a comma after "it showed the same"
    That makes more sense anyway......if it has no compression there, it would have a miss there anyway wouldnt it?
    Would one be as well off to just leave that plug wire off and have only a miss, not burning the oil in that cylinder causing less smoke? "theoretically" speaking?o_O until he comes up with a fix?
     
  23. There isnt any combustion in that cyl anyhow because of zero compression. The oil is simply going into the exhaust and being heated and burnt there. If he had four straight pipes one would remain cold and oil would drip from it. Im thinking his valves are good. if he has a problem that is so bad the one cyl has zero compression he really is taking a risk driving it. he could cause farther damage.
     
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  24. RichFox
    Joined: Dec 3, 2006
    Posts: 9,693

    RichFox
    ALLIANCE MEMBER

    It sounds a lot like that piston is trash. Really only one fix. Or replace.
     
  25. 56cadillackid
    Joined: Dec 23, 2016
    Posts: 94

    56cadillackid
    Member
    from new york

    I really appreciate all the input the piston rings or the piston being junk seems to make sense and explain the smoke coming from the crack case vent. I'm going to college in a few months so I dont really have the money for a full rebuild so it might be time to sell the Cadillac.

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  26. 56cadillackid
    Joined: Dec 23, 2016
    Posts: 94

    56cadillackid
    Member
    from new york

    Wow that's even more smoke than my car is making right now.

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  27. 56cadillackid
    Joined: Dec 23, 2016
    Posts: 94

    56cadillackid
    Member
    from new york

    No I meant that the other pistons on that side of the engine were good or at least ok. The piston that had no compression still showed no compression when I tested it again.

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  28. Ebbsspeed
    Joined: Nov 11, 2005
    Posts: 4,624

    Ebbsspeed
    ALLIANCE MEMBER

    If you have an out of the weather place to store it, keep the car and fix it when you have the resources (money and people to help) if at all possible. It's a sweet looking old Cad .
     
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  29. al1630
    Joined: Jun 18, 2019
    Posts: 5

    al1630
    Member

    If you pull the engine apart and the block itself isn't damaged, you might be able to get away with just honing and replacing the bad piston and putting in new rings. That's what I did in my Rambler with broken pistons, and now it doesn't smoke and burn a quart of oil every 20 miles.
     
  30. And if you take it apart and for some reason cannot get it fixed. Your much worse off than you already are. It becomes a non running vehicle. Kinda a durned if you do and a durned if you don't situation.
     

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