Trouble with '66 300

Engine, Transmission & Driveline

  1. Justin Heydon

    Justin Heydon New Member

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    All,

    Just finished up a full engine bay restoration on my 1966 300 convertible. Engine completely rebuilt, new Edlebrock carb with a heat spacer, all new wiring, new MSD distributor and coil. It ran great a couple of weeks ago once the weather broke but now we can only drive a couple of miles and the engine stalls sputters and then eventually dies. After it dies we have to wait several hours before it will start again. After it dies, we check to see if there is any gas still in accelerator pump and there is not.

    My question is are we experiencing vapor lock? We have 93 octane in the tank. The timing is set to 16 deg BTDC. Could that be too much causing an overheating problem?

    Justin WV
     
  2. cbarge

    cbarge Senior Member FCBO Gold Member

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    Your timing is advanced. Retarded timing causes overheating. Answer is no.
    You could be experiencing vapor lock.
     
  3. 69Ragtopfury

    69Ragtopfury New Member

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    When it dies, you say there is no fuel at the carb. Have you checked for fuel flow when trying to restart it?
    How many miles is a few miles of driving before it dies? Just a few miles shouldnt get THAT hot under the hood. After the addition of the new carb, is the fuel line running up against the block/head or really close to the exhaust manifold - to cause vapor lock? Crud in the tank getting sucked up in the sock, and eventually falls away allowing gas to flow again? Fuel pump failing and not keeping up at higher rpms?
     
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  4. Ripinator

    Ripinator Senior Member

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    In addition to the other suggestions made here, you should also check the vent tubes at the gas tank. If the tank doesn't vent properly, there will be a vacuum created that could prevent the flow of fuel forward to the fuel pump. Also check the fuel filter for clogging / flow.
     
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  5. Justin Heydon

    Justin Heydon New Member

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    We have not checked while trying to restart. We will do that.

    A few miles being around 5? Really nothing. The fuel line is still the original hard pipe from the mechanical fuel pump which runs over the valve cover. We wrapped it in heat tubing but still no avail.

    We will check the sock. The fuel pump is brand new.

    Just discouraging.
     
  6. detmatt

    detmatt Old Man with a Hat FCBO Gold Member

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    After it dies next time remove the fuel line from the carb and stick the end in a water bottle, next crank the engine and see what comes out into the bottle while cranking.
     
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  7. 69Ragtopfury

    69Ragtopfury New Member

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    Start here when you find you have no fuel flow when cranking.
     
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  8. detmatt

    detmatt Old Man with a Hat FCBO Gold Member

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    And when you pull the pump next because of the lack of flow check the length of the fuel pump pushrod before just replacing the pump.
    Did you replace all of the rubber hose between the tank and the engine? You could also be sucking air into the system through old rotted hose or bad connections.
     
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  9. mr. fix it

    mr. fix it Old Man with a Hat

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    I had a defective $15 B/N fuel pump too. (AZ Special I guess...)

    Changed it out and been running great since
     
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  10. Mike66Chryslers

    Mike66Chryslers Active Member

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    I was going to say the same thing about the pushrod. Sounds a lot like the symptoms I was having when my fuel pump pushrod was wearing down.
     
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  11. Justin Heydon

    Justin Heydon New Member

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    What should the length be? It's a brand new pump?
     
  12. Mike66Chryslers

    Mike66Chryslers Active Member

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    3.2"
     
  13. Big_John

    Big_John Illegitimi non carborundum FCBO Gold Member

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    This is a very basic diagnostic procedure that an awful lot of guys ignore. All it takes a piece of hose and a coke bottle.
     
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  14. detmatt

    detmatt Old Man with a Hat FCBO Gold Member

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    Your fuel pump and your fuel pump pushrod are two separate things. The fuel pump pushrod is located behind that Allen headed pipe plug just below the pump itself. And yes 3.2” or 3 3/16”. The first one that I discovered was worn after a long time of troubleshooting was a full quarter inch shorter than it should have been And then the same engine ate another one Which I caught it just under 3 inches. I run new ones that are properly hardened now.
     
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  15. Ripinator

    Ripinator Senior Member

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    So true. . . A hard rod is a happy rod. . .
     
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  16. BLUPORT

    BLUPORT Carpe Diem Cras FCBO Gold Member

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    Mine's not happy until it's finished pumping.
     
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  17. Trace 300 Hurst

    Trace 300 Hurst Well-Known Member

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    I've seen this twice. The short hose at the tank doesn't leak gas (yet) because there's very little pressure, even with a full tank. But the slightest minuscule crack in that hose will allow the car to start and run just fine, but will suck air when engine speed and load (fuel) increases in the highway.

    Also...your tank vents are not obstructed with mud or insects or whatever?
     
  18. Trace 300 Hurst

    Trace 300 Hurst Well-Known Member

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    Not if it's only 3.2 inches.....
     
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  19. Justin Heydon

    Justin Heydon New Member

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    Awesome thanks guys. I have a lot to look in to. I'll keep you posted.
     
  20. Cazman

    Cazman Member FCBO Gold Member

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    I always wondered - do we need to have the OEM style distributor cap with the vent? Many replacements do not have it. Can moisture accumulate without the vent?