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Engine Problem

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  • Engine Problem

    Good Morning. I need help with an engine problem on my 1964 289 V-8, bored .030 with only 5000 mi. on a pro rebuild. The car is a 1961 Hawk with 4speed. It will start easily and run smoothly up to 2500 rpm where it cuts out abruptly and will not go higher. It will run smoothly again if you let off the gas. this occurs under load or no-load conditions.
    Background: Coil shorted out, took resistor and some wire with it. Replaced coil and in trying to get it going again the distributor shaft broke. Replaced it with a rebuilt dist. with a Pertronix module and Pert. coil with int. resistor; also new cap and rotor and dist. to coil high volt. lead. This is when I became aware of the rpm problem. Timing looks right on. Adjusted valves cold, then hot. Checked compression- #5 slightly low-142# vs. 156 avg. for others. No help. Noticed fuel pump leaking: replaced with rebuilt pump and replaced filters. No help. Had carb. rebuilt and tested. No help. Starter pinion gear broke. Thought maybe starter wasn't disengaging. Installed rebuilt starter. No help with original problem.
    The only other thing--I can hear a slight knocking or tapping sound ( kind of hollow ) that speeds up with the engine but does not get louder. I can't isolate it, but don't think it's related to the rpm problem.
    Any ideas.

  • #2
    Disconnect the coil to cap wire and fuel line and put a hose on the end of the line into a coffee can and crank it over. Are you getting a good stream of gas or a trickle? If you're getting a weak stream or trickle you either have a weak pump,bent actuating pump rod,pin holes in the fuel line sucking air,clogged line,or a blocked fuel vent. If the stream is strong check your float level. As to the noise it can be anything from a fan belt to an internal engine problem. Use a section of heater hose as a stethoscope to narrow down the location,be careful around moving dangling sleeves,jewelry,hair etc. It won't hurt any thing to run it for a couple of minutes without the belt to eliminate it as the noise culprit. I wouldn't worry about the slightly lower compression in # 5.

    63VY4 Leakin' Lena Hagerstown MD


    • #3
      If it cuts out at 2500 PRMs with no load, chances are it is the ignition. If it were the carb or fuel pump, it would behave dramatically differently, load/no load. As the book says swap the distributor/coil with a known good unit.

      thnx, jack vines



      • #4
        Jack...I think he said he did swap everything with new Pertronix stuff.

        This is a tuff one with the available information.
        Could be a lot of things...including a "combination" of things.

        Even down to loose wires at the ignition switch or solinoid.

        If the original coil shorted out...check the entire electrical system for shorts, loose connections AND...breaks in the wires that may be hidden by the insulation!

        Good luck.



        • #5
          Have you tried to blow air BACK thru the fuel line from the pump?
          Also you might want to check output pressure at the carb, 5-7 psi?
          You didn't mention when your tapping sound began, if it started
          with the rebuilt pump the pump might have the wrong arm, did you
          compare the replacement pump with the original? Keep up with the
          posting, someone will have a solution to your problem. Good luck


          • #6
            Thanks to all who replied. It is getting plenty of gas. I am now in the process of going back over all the ignition wiring and attached things like the tach.


            • #7
              If it cuts out abruptly at 2500 RPM every time, I think it would be ignition-related. If fuel supply were the problem, it should exceed 2500 RPM for a few seconds, until the fuel supply in the carb bowl was exhausted.

              I'd be looking real close at the advance mechanism in the distributor. Maybe the centrifugal or vacuum advance is moving the reluctor out of range of the pickup coil?

              This is the kind of problem where an engine scope is really useful.

              Gord Richmond, within Weasel range of the Alberta Badlands
              Gord Richmond, within Weasel range of the Alberta Badlands


              • #8
                Have you tested the distributor advance? The R2 distributor uses a combination of mechanical and vacuum.

                You may also wish to check the heat riser valve to make certain that it isn't stuck closed.

                63 Avanti R2, 4-Speed, 3.73 TT
                Martinez, CA


                • #9
                  years back I ran a stock car and chased a similar problem we found it to be a bad tach. would rev to 3600 and start shooting ducks.

                  quote:Originally posted by jbenner

                  Thanks to all who replied. It is getting plenty of gas. I am now in the process of going back over all the ignition wiring and attached things like the tach.


                  • #10
                    Do Pertronix use a condenser? I'd replace it if it does. I know this sounds stupid, but it could also be the rotor or the distributor cap.

                    Tim K.
                    '64 R2 GT Hawk
                    Tim K.
                    \'64 R2 GT Hawk