Improving acceleration using 2bbl Carburetor?

Slant 6 Engines

  1. Machmeter1

    Machmeter1 FABO Gold Member FABO Gold Member

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    I do not know your budget and your project objectives. First, determine what you want and how you want to reach this goal. I came from the Ford corner and had till October last year no clue about Mopar. Even after many years working on a classic Ford, when I got my Barracuda, I did not touch it for two months, started reading Service Manuals, transmission books, reviews/availability of parts, and spent uncounted hours reading articles on this great forum and other webpages.

    Finally, I made a project plan, a list of needed parts, vendors, and got in contact with knowledgable members here on this forum. Back in Austria, I had a very well equipped shop, but here in the US, my mancave is more or less an empty mousehole.

    What I want to tell you with this:
    Do you have space, tools, a lot of time (month/years), then build up a network of capable guys, learn and do most things by yourself (not everything should, or can be done by yourself), but be ready to have many setbacks, to spend nerves and a lot of money.

    No space, no time, not really interested in the technic, then build up a network, find a really good, well-established engine builder/Mopar mechanic in your area and spend nerves and a lot of money.

    Whatever way you choose, it will be a bumpy road...

    Cheers,
    Wolfgang
     
  2. chinze57

    chinze57 Push Button tranny and a Slant 6 that'll never die FABO Gold Member

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    I’ve been having an issue for the past month or two where it takes a few tries to start it. If I’ve just driven it, stopped to run an errand, and then get back in, it starts up in a second or two. But when I’m starting it for the first time that day it takes two or three tries to get it cranked. If i drove jt around and then don’t drive it for a few hours (still warm but not hot) it takes several tries.

    I think this is an issue with the timing of the ignition. The distributor and starter were initially replaced back in November/December and had the timing set. Started and ran fine consistently then. The distributor gunked up and was replaced back in February, and the timing was set. It started and ran fine consistently. But now it doesn’t.

    Is it a heat/humidity thing? I’ve read up on and watched videos on how points and condensers ignition works, how adjustments are made, but don’t totally understand it. A teacher of mine owns a ‘72 charger and put a converter in place of the points/condensers that is, as I understand it, a magnet and pickup that doesn’t require adjustment. Would an HEI conversion help with cranking? Note: at one point I had trouble cranking due to a bad alternator wire and it was draining the battery trying to crank that. That does not seem to be the issue here.
     
  3. Mattax

    Mattax Just the facts, ma'am FABO Gold Member

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    I'll do my best.
    That's not unusual depending on how you prime it (pump thr throttle) and the choke setting. On a '64 factory settings for idle and choke should provide pretty good starting in all conditions. But today's fuels have distilation curves that can make it starting a little more difficult after the fuel has been sitting in the bowl for a while.

    Yes the initial timing can make it easier or more difficult to start the car.
    I am concerned that the distributor has been replaced and replaced twice.
    I'm also concerned about what 'gunked up'.

    Well you don't need to understand how they work to make the adjusments. Just follow the procedure.
    Doing so may help you pick up on how they work. A lot of us learn like that. We can read about it, and we can work on the parts, but only when we do both are we able to understand what they do.

    Pretty much the same answer I gave before about electronic ignitions in general.
    IF the combustion conditions are such that a slightly higher voltage will initiate spark and if more current will build a better flame kernal so there's a good burn instead of a misfire or incomplete burn, THEN yes.
    So in other words, if something is going in inside the cylinder that is making it difficult to initiate combustion, then a good HEI or similar setup may be able to overcome those conditions.

    Not sure what you are describing.
    A battery that doesn't get recharged will definately make it difficult to start.
    Otherwise the alternator isn't involved in starting.
     
  4. chinze57

    chinze57 Push Button tranny and a Slant 6 that'll never die FABO Gold Member

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    I pump the throttle three or four times before I crank it usually, and if it gives me trouble starting I pump it a few more times during. As I’m doing my tune-up I’ll make sure the choke and idle settings are matching what the FSM recommends and see how that does.

    It was replaced initially when I first bought the car because the previous owner pretty much ignored everything. For instance: He bought a new stereo and speakers and cut the dash installing them, removed the bench seat and installed cheap buckets from a modern Toyota, etc. It’s hard to find any work that he had done that was really for the maintenance of the car.

    As such, the starter was replaced with a reman unit and the distributor was replaced, to be safe. After driving it around for a few hundred miles, the car sputtered while driving one day and quit on me. After trying everything I could think of to sort it out, I called a teacher of mine and he came and took a look. He popped the distributor cap off and it was essentially black all around inside. He scraped and cleaned off the points and then I was able to crank it and it ran fine for a few minutes before having issues again. I wish I had pictures. My mechanic replaced it under warranty. That black stuff is what I’m referring to as “gunked”

    I figure as much. Adjusting it will help me learn about the process as well as how it works. I’m very interested in it, but trying to wrap my head around it at the moment is giving me trouble. Just form to get out their and get my hands dirty.

    What I just don’t know is if it’s an issue with the engine. Given that it has no issue running other than starving for fuel under some idle conditions, I don’t think it’s a spark issue. What I’m seeking is reliability. Its entirely possible that the issues I’ve had related to the distributor are cheap distributors, or the result of road splash given that the distributor sits low to the ground on the slant.

    The issue I ran into was that my battery wasn’t being recharged, making it difficult to start. For a few days (maybe 2) i was able to start after a try or two and then it was fine. Just driving 2 miles to and from work. Then the starter would barely turn over. After a jump, it started fine.
     
  5. Machmeter1

    Machmeter1 FABO Gold Member FABO Gold Member

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    Regarding the distributor and other parts:
    A picture is worth a thousand words, so it might help if you post clear and detailed pictures of damper, distributor (with and without distributor cap), spark plug wires, spark plugs, wiring at the battery, fuel line routing, etc.
    An overall picture of the engine bay would be good too. If the distributor is bad or needs to be serviced, I recommend @halifaxhops, he might service yours or have a tested and working unit for you.

    It seems like there is a general maintenance backlog at the engine bay.

    Cheers,
    Wolfgang
     
  6. Mattax

    Mattax Just the facts, ma'am FABO Gold Member

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    That's worth peeking at again.
    Should be clean in there.
    Cap with oil inside is odd but maybe @halifaxhops has some ideas.
    If it was carbon, that's an awful lot of carbon tracking.
    Either way these become easier paths for electricity than having to jump an .035 gap in a high pressure chamber!
     
  7. Mattax

    Mattax Just the facts, ma'am FABO Gold Member

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    Two miles a day may not be enough to recharge a battery that was run low.
    It also can be hard on the charging system.
    Observe the ammeter to see what its indicating; after starting, while driving, and before shutting off at work or home.
    If its charging high for any length of time and/or still charging at all by the time complete the trip, then put the battery on a charger at low current (2 amps).
     
  8. BillGrissom

    BillGrissom Well-Known Member

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    To answer the OP's initial question - no, a 2bbl carb will not improve initial acceleration. It will breath better to give maintain torque at higher rpm, thus more max power. If anything, it will give poorer performance at low rpm, like when starting from a stop. Good that you have the BBS. My 1964 has the same, and for those that don't know it is rod-operated (no cable). My 1969 slant had a Holley 1920 and it was terrible, going thru ~4 over 18 years before I finally got a rebuilt one which ran perfect. I had been thinking valves, intake leaks, and such, plus no mechanic could find why it ran poorly and stumbled around idle. The Carter BBS is similar to the more common BBD. I don't know if many parts interchange, but the knowledge does and you can find posts how to tune and rebuild it. I think its direct descenant is the popular Edelbrock 4 bbl used on maybe 90% of small-block Chevy's you see at car shows.
     
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