Improving acceleration using 2bbl Carburetor?

Slant 6 Engines

  1. chinze57

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

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    I've got points distribution, which I understand is not ideal.
     
  2. RustyRatRod

    RustyRatRod Bla de blizhibliz de blatde blizi bla bla FABO Gold Member

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    He may well not be familiar with carburetors. That's fairly common nowadays.
     
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    • George Jets

      George Jets 1967 Dart 2 Door FABO Gold Member

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      Keep the points distributor, you just need to put a set of contact points in it for your tune up, then you get good spark.
       
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      • chinze57

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

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        It's a 270 /6. How do I adjust valves and "baseline" the car back to tune, and what tools would I need?

        I'm fully on board with doing everything I can to get it to run better before I upgrade it or throw money at it. This car is stock when it comes to the engine bay. Front brakes have been converted, but off the top of my head that's the only real change that's been made. I want to get it to running its best and then figure out what to do from there

        Edit: Just realized slant six dan provided me with a valve adjustment link
         
        Last edited: Jul 9, 2020
      • chinze57

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

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        That's probably it. He's an older guy, and while he does a good bit of work on classics (working on a '66 dart and '73 dart), a lot of the cars have EFI now. The car was also in terrible shape when I got it to him
         
      • Tooljunkie

        Tooljunkie King of cobble/master of the broken bolt FABO Gold Member

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        Just replacing points isnt all of it. The vacuum advance needs to be checked, and mechanical as well. If parts are worn,there is some of your performance as well. Timing, valve adjustment and proper fuel management will get you where you need to be. A compression test will help determine condition of engine as well.
         
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        • SIX225

          SIX225 Well-Known Member

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          My '68 when I got it ran, but poorly. Similar to yours, weak on power, ran hot. It had been in storage when the original family brought it back to life. Work looked like it had been done at a shop that was previously the Chrysler dealer in town. I agree with not a lot of people are familiar enough with these cars anymore.

          Carb was replaced with a reman unit. It was awful. Float wasn't even close to being adjusted. Check it/ teak it down even if someone says its rebuilt. Biggest single improvement. Mine went from afraid to pull out into traffic, to reasonable.

          Went through distributor. Weights were stuck, advance can not operating.

          Heat riser stuck.

          Not saying I wouldn't make upgrades, but get what you have to a reasonable running point. IF you can't get what you have to work properly, how do you expect to throw parts at work and for those to work properly.
           
          Last edited: Jul 10, 2020
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          • halifaxhops

            halifaxhops It's going to get stupid around here! FABO Gold Member

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            I have to go with TJ on this by chance was it changed with a store rebuilt? Can be as easy as it having the wrong curve in it.
             
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            • dddDuster

              dddDuster Well-Known Member

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              I really think you need to do a systematic fix-up/ tune-up on your car. Valve adjustment, spark plugs points and timing, then carb adjustment. In that order! No one seems to have mentioned to you that changing to a two barrel is not bold it off bolt it on. You must change the intake manifold, will probably find the exhaust manifold is cracked and needs replaced, need to figure out the linkage to operate it, figure out and set-up a choke for it. After all that you have to find, go thru and tune the carb. You WILL have at least $500 in it by the time your done. Makes much much more $ense to get what you’ve got performing properly first, then upgrade as you choose.

              Also, try to commit to doing it yourself, you’ll learn a lot and know where to start when the next thing comes along!

              Cheers
              Tim
               
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              • Mattax

                Mattax Just the facts, ma'am FABO Gold Member

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                Great minds think alike. :)

                The other thing most mechanics won't have is the tune up specs. Even if they have service like Alldata, it usually only goes back to mid 70s.
                And the initial timing, as well carb tuning for a '66 225 is way different than a '75.
                My suggestion is to clean things up so you can find the tab or stamped numbers and see what distributor and carb is on the engine.

                If you want some general background these cover the basic concept
                The New Distributor (Session 136) from the Master Technician's Service Conference
                1967 Imperial & Chrysler Engine Combustion - Session 240
                 
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                • chinze57

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

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                  I’m going to start assembling tools (feeler gauges, etc) and the parts necessary for a tuneup and do one. Then I’ll start working on adjusting the carburetor. Thank you!

                  Edit: I purchased feeler gauges, a fender cover, and a new gasket from real gaskets and will get to work when it all arrives.
                   
                  Last edited: Jul 10, 2020
                • chinze57

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

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                  I’m going to check through my receipts and see I can discern whether they rebuilt the carb that was there or got a remanufactured/rebuilt unit. Then I’ll start with a tuneup and get that done. I have a FSM (whereas I highly doubt they do) and I’ll start reading through the tuneup specs to see what I’m shooting for. Thank you for y’all’s help so far
                   
                • slantsixdan

                  slantsixdan =..=

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                  Look at post № 11 in this thread (on the first page). Wherever you see boldface, blue type, that's a clickable link. Click it to go to the information it represents. As you are new to all this, as soon as you can, get the three books listed in this thread.


                  Wise. See this thread about that.

                  Note there is nothing such as a 270 Slant-6. "270" is the model series of your Dart. The 170 was the basic/low-trim series. The 270 was the high-trim series. The GT was the premium series. It's a little confusing because the standard-equipment engine was a 170 cubic inch Slant-6, but any Dart model could be had with any of the available engines. Your engine is either a 170 or a 225 Slant-6. Look at the driver's side of the engine block, below/behind the manifolds. What casting numbers do you see?
                   
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                  • chinze57

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

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                    Interesting. I assumed the 170 came with the 170 ci engine and the 270 came with the 225 ci. I shall check and see what casting numbers are there.

                    Edit: I have a CD version of the FSM purchased from moparmanuals that the previous owner gave to me. It blows my mind how much info and procedure for everything is in there. I will get those other two books as well. I also read your other link. Excellent information and gave me some ideas of where to focus attention. I'm currently dealing with a number of various things about the car and trying to prioritize (suspension, tune-up, carburetor issues, interior, etc etc) but you've provided links and reasoning behind a lot of decision to be made. I got three point seatbelts in and don't know how I was comfortable driving without them for so many months.

                    I do, however, have some questions about the HEI conversion. I read your entire post. Is the HEI ignition more reliable than points and condensers? Does it result in more power? I see that you mention it has more complete combustion, so I expect it does see a power benefit.
                     
                    Last edited: Jul 10, 2020
                  • Mattax

                    Mattax Just the facts, ma'am FABO Gold Member

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                    If you put enough miles on and fail to check and replace the points, in general a transitorized ignition will be more reliable. More power? IF the combustion conditions are such that a slightly higher voltage will initiate spark and more current will build a better flame kernal so there's a good burn instead of a misfire or incomplete burn, THEN yes. Slightly anyway. IF it means running a timing curve that doesn't build pressure through the most efficient crank angles, then NO.
                    See the first link I posted above.
                     
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                    • Machmeter1

                      Machmeter1 FABO Gold Member FABO Gold Member

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                      I am running a stock, 1969, LA 318 (besides pistons .030 over), and original Carter 2 bbl carburetor. Engine and carb recently rebuild and Dyno tested. Please note the correct location for the carb vent linkage - had it wrong first time but corrected and marked it. Electronic ignition (thanks @halifaxhops)
                      Attached are the facts from Dyno test with original carb and air cleaner:

                      IMG_20191215_180922170.jpg

                      IMG_20200113_095345119.jpg

                      IMG_20200115_211302498.jpg

                      IMG_20200115_211335923 (3).jpg

                      IMG_20200115_211342027 (2)_LI.jpg

                      IMG_20200328_093125137.jpg

                      IMG_20200404_213727428.jpg

                      IMG_20200404_213749877.jpg

                      IMG_20200104_105619864.jpg

                      IMG_20200215_095922257.jpg
                       
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                      • chinze57

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

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                        03FEE5B8-271A-42AB-9DE6-110DB7579594.jpeg CE4E0034-E622-45CF-9F9B-A02DDB4068F1.jpeg 41C127F0-DCEA-4CFE-BE80-37FDE81885B3.jpeg
                        Here are some photos I got of my carb. It appears to be made by Carter judging from the information cast on the side.
                         
                      • nitro_rat

                        nitro_rat FABO Gold Member FABO Gold Member

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                        Yes, that's a Carter BBS
                         
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                        • chinze57

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

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                          Where would I look to find a good rebuild kit for it?
                           
                        • 66fs

                          66fs FABO Gold Member FABO Gold Member

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                          most anywhere 60's Carter BBS, look for a kit for 68 273 or 318?
                           
                          Last edited: Jul 11, 2020
                        • Machmeter1

                          Machmeter1 FABO Gold Member FABO Gold Member

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                        • 69a100

                          69a100 Well-Known Member

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                          There's more than a wealth of knowledge in the FSM, Read, Study and Learn that manual inside & out! It will bail you out more often then not. Good Luck
                           
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                          • slantsixdan

                            slantsixdan =..=

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                            No. The BBS ("S" for "Single barrel") was used on 170s and 225s. That's the kind of carburetor the original poster has. The BBD ("D" for "Dual barrel") was used on 273s and 318s, and is not applicable to the original poster's car.

                            Parts store carb kits have dropped very far in their quality and completeness. Go get a good kit from www.thecarburetorshop.com . You'll probably have to ask for a float gauge separately; they don't tend to come with kits any more—at best you get a useless little strip-of-paper ruler. See here for workaround.
                             
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                            • 65 Cuda 340

                              65 Cuda 340 Well-Known Member

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                              A 64 Valiant is almost 60 years old. If you have one with an unknown history that does not run well, you need to check a bunch of things you probably wouldn't on a five, ten or even 20-30 year old car. So, in addition to the usual plugs, points, valve adjustment, etc., I would check the following:
                              1. Do the centrifugal and vacuum advance mechanisms in the distributor work?
                              2. Is the TDC mark on the harmonic balancer in the correct place? If not, you can't time the motor correctly.
                              3. Is the muffler clogged? I've seen 'em clogged so badly the motor would barely run. One el cheapo way to test is to hacksaw the exhaust pipe ahead of the muffler and run it w/o the muffler (not permanently, of course).
                              4. Does the heat riser valve work properly?
                              5. Do a compression test.
                              PS: an exhaust manifold leak is not a "vacuum" leak. (Intake leak, yes, exhaust leak, no. Bad vacuum hoses can also be a source of a vacuum leak.)
                              PS2: On the idle issue, especially when cold, have you adjusted the curb idle screw or the fast idle screw?
                               
                            • chinze57

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

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                              The muffler was replaced around 4 years ago and is not clogged. When I adjusted the idle, i believe it was the fast idle screw. The engine was timed by my mechanic when I first got the car, so I don’t 100% know if the harmonic balancer is correct, but I suspect it is. What am I looking for there?
                               
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