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Technical Carb/fuel system assistance

Discussion in 'The Hokey Ass Message Board' started by Kustom55, Mar 29, 2022.

  1. Man, it feels like forever since I have posted here.
    I need some direction; I am hitting a mental block with all this. Currently, I have a 55 Star Chief running the original 287 V8 (pic for a visual). A few months ago, the car started to blow smoke from the exhaust which became more prevalent and worse on startup, idling, and acceleration. Also, the car would completely die if I made right turns up any sloped street. I replaced the gas tank with a new one, all new fuel lines, a new fuel pump, fuel filter, and rebuilt the carb. New oil, new filter, and new gas, and voila! I am back on the road. I drove the car all day this past Sunday to "break everything in" and I am still noticing some white smoke on start-up and acceleration. Not bad at all; but definitely there. Towards the end of the day, the car died making a right turn up a slightly sloped street. It felt like the more I drove it, the more it wanted to revert back to its prior issues.
    Any idea, based on the above, what I could be missing which would still cause both of these issues?
     

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  2. Doublepumper
    Joined: Jun 26, 2016
    Posts: 1,535

    Doublepumper
    Member
    from WA-OR, USA

    Possibly carb. float leaking or set too high.
     
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  3. BJR
    Joined: Mar 11, 2005
    Posts: 9,818

    BJR
    Member

    White smoke is coolent in the combustion chamber. Bad head gasket, etc.
     
  4. squirrel
    Joined: Sep 23, 2004
    Posts: 55,945

    squirrel
    Member

    black smoke is from excessively rich mixture, blue smoke from burning oil, white from coolant. But these colors are kind of general, and you may or may not see them the same way that others see them.

    It does sound like you have an issue with the fuel level in the carb bowl, but I've also had cars die on turns because of electrical issues. And the white smoke...I'd have to see it myself to figure out what might be causing it. Might want to pull out spark plugs and see how they look, just to get a start figuring it out.
     

  5. 2OLD2FAST
    Joined: Feb 3, 2010
    Posts: 5,217

    2OLD2FAST
    Member
    from illinois

    Check float level ,needle & seat , look for bubbles in the radiator ,pressure check cooling system , get coolant test strips from Napa or others to check for combustion gas in coolant , use heat gun on exhaust manifold , although doesn't that Pontiac have siamesed exhaust ports ?
     
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  6. NoelC
    Joined: Mar 21, 2018
    Posts: 668

    NoelC
    Member

    I asked my buddy Kevin a while back why the first thing out of his mouth is did you do a compression test? You know what he told me...? Because it makes you take the plugs out.
    Thinking about it ( and I did), you not only get a visual inspection of plug condition, if fouled, the compression test reveals symptom conditions.
    While most think head gasket leaking into a combustion, it can as well leak into the lifter valley.
     

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    427 sleeper and VANDENPLAS like this.
  7. Like what @squirrel said .

    carb issue

    possible head gasket , does the intake have a coolant passage ?
    Can you smell a sweet smell from the exhaust ?
    That’s a indicator of burning coolant

    pull the plugs if it’s nipping at coolant you should have one plug that’s clean compared to the rest .

    I had an O/T car that would cut out on turns and ended up being a loose ground .

    you should be able to get a coolant sniffer from one of the loan a tool places , easy way to check for exhaust gasses in the cooling system .

    bad engine mount pulling the carb linkage closed ? Maybe ?
     
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  8. 427 sleeper
    Joined: Mar 8, 2017
    Posts: 2,872

    427 sleeper
    ALLIANCE MEMBER

    Does it smoke worse when it's hot or when it's cold? What does the connector look like at the firewall or anywhere else the harness passes over a sharp edge, like firewall clips? What does the primary lead look like going into the distributor? Lots of factor's at play here.
     
  9. Wanderlust
    Joined: Oct 27, 2019
    Posts: 788

    Wanderlust

    Another electrical possibility is the ignition switch, do you have a large bunch of keys on the ring or something heavy?
     
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  10. Great idea; I only have the ignition key on a single ring. However, it is the original ignition. Definitely something to check out.
     
  11.  
  12. All great questions; I will dig deeper at all those. When it does smoke, it happens in cool or warm weather.
     
  13. Great point! Compression test was good and all plugs have been replaced and gapped to spec.
     
  14. 427 sleeper
    Joined: Mar 8, 2017
    Posts: 2,872

    427 sleeper
    ALLIANCE MEMBER

    Does this mean that it smokes constantly, or occasionally?
     
  15. Thank you; I started the 55 tonight and the smoke is more blueish than white. After a quick puff of smoke, it idles nicely and no smoke or smell of anything sweet out the tailpipes. I drove it around the neighborhood and even though it didn't die on turns, it was hesitating on each take off. A ground issue is a good idea and definitely something I will chase down; I am however leaning towards the carb.
    Thanks for all of the replies, everyone. I appreciate it.
     
  16. Briefly on start up and briefly taking off for a green light; it does not smoke during idle
     
  17. 427 sleeper
    Joined: Mar 8, 2017
    Posts: 2,872

    427 sleeper
    ALLIANCE MEMBER

    That could be valve guide's. Not a big deal until you start fouling plug's because of it. Check the wire from the points to the coil very closely, they have been known to deteriorate inside the insulation, hidden from plain sight.
     
    Last edited: Mar 29, 2022
    Kustom55 likes this.
  18. Worn valve guides and/or valve seals tend to show up mostly during conditions of high manifold vacuum. That would be at idle, steady light throttle cruising and deceleration. Sometimes it will also show up on a cold start up after a bit of oil has had time to drain down through the valve guides. Check under the valve covers and make sure the oil drain back holes in the heads aren't gunked up.
     
  19. squirrel
    Joined: Sep 23, 2004
    Posts: 55,945

    squirrel
    Member

    A little bit of blue smoke is normal on an older engine that's got some miles on it.

    There are a lot of things that can cause hesitation, the most common are retarded ignition timing, accelerator pump not working, and a vacuum leak or lean idle mixture. Also if there's a problem with the engine inside, such as a worn cam lobe, weak valve spring, burned valve, bad rings in one cylinder, etc that would cause low compression, then it's likely to stumble on acceleration.
     
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  20. Joe H
    Joined: Feb 10, 2008
    Posts: 1,525

    Joe H
    Member

    How does it restart when it dies? Does it fire right up? crank awhile? smoke a lot once started? need to set?

    A quick and easy test, pull the air cleaner off so you can see down the throat of the carburetor, with engine off, open the throttle quickly. Did you see fuel shoot down the throat?
     
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  21. ekimneirbo
    Joined: Apr 29, 2017
    Posts: 4,217

    ekimneirbo

    I would take a compression check and spark plug check just to verify condition rather than chasing an unknown. If all is good, I would run the engine at night in the dark and look for any spark jumping. I would also buy a new coil and check the wiring to the coil. I say that simply because a loose connection can appear ok and be difficult to find. As for the coil, I'd replace it just because its old. Last thing I would look at is float level. Sometimes floats can get pin holes in them and fuel gets inside. Then they don't float as high and the bowl contains less gas. I had a friend who crashed his newly restored airplane on its maiden flight because a professionally rebuilt and certified carburetor had a hole in its float. Destroyed the airplane but he walked away.
    Had another friend whose vehicle kept dying while driving and it was a loose wire connection.
    One question: When it dies, do you have to crank it awhile to restart or does it restart instantly? If it takes a bit, I'd check for spark quickly with an extra plug to stick in a wire. If it doesn't start immediately but you are getting spark........then its a fuel problem.
     
    Kustom55 likes this.
  22. Thanks for the additional comments, everyone. When it does die, it fires right back up with no issues and no smoke.
     
  23. jaracer
    Joined: Oct 4, 2008
    Posts: 2,419

    jaracer
    Member

    In my experience, a good size puff of blue smoke when first started points to bad valve guide seals. When I worked for a Dodge dealer we would see this on 440's. You would pull the valve covers and see rock hard pieces of valve guide seals near the drain holes in the head.
     
  24. 1971BB427
    Joined: Mar 6, 2010
    Posts: 8,720

    1971BB427
    Member
    from Oregon

    Have you changed the oil and filter since you reworked all the fuel system? It's possible the oil is diluted if you had a rich carburetor before, and is still thinned out and is causing lingering issues. Thin oil diluted with gas can really be harmful to bearings and rings, so best to get fresh oil in after any flooding or rich conditions are fixed.
     
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  25. ekimneirbo
    Joined: Apr 29, 2017
    Posts: 4,217

    ekimneirbo

    If it fires right back up, then it could be either a loose connection/electrical issue or fuel. I was hoping it would NOT fire right back up as that would make it easier to pinpoint. I'd still put a new coil on it just because of its age as it could have an internal issue.....and it could fail later even if its good now.
     
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  26. 2OLD2FAST
    Joined: Feb 3, 2010
    Posts: 5,217

    2OLD2FAST
    Member
    from illinois

    With any 1955 component , "failure prone" pretty much goes with the territory.:cool:
     
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