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  • #1

    But not as alive as I thought

    Bummer, Dudes and Dudettes -
    I just got back from the dyno, and all is not well. Apparently, the carb that Dave rebuilt (Holley vacuum secondary 600) has something seriously wrong with it, and we don't think it's Dave's rebuild. Even with #70 jets in the front, he couldn't get the AFR on scale - WAY too lean. He tried a bunch of stuff to diagnose it better, but it's essentially screwed. The secondaries also don't open at all. As a result, it's backfiring like crazy. Idles OK, and the AFR at idle is acceptable.

    The distributor isn't good either. It doesn't advance smoothly, and is unrepeatable at both idle and max advance (we were shooting for 33 as a starting point).

    Besides that, the headers are leaking like crazy at the header flange.

    So bottom line - no racing for me this weekend. I, of course, will be there. To make matters worse, we'll be traveling for three weeks following this meet (this weekend), so I likely won't get a chance to resolve this stuff before the June meet. A bummer, but that's the way it is.

    If money was no object, I know exactly what I'd do, but.........

    Later
    Dan


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  • #2
    Re: But not as alive as I thought

    Been there, Dan. I know exactly how you feel. There'll be more races.
    Cognizant Dissident

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    • #3
      Re: But not as alive as I thought

      Better to get it right first and not blow everything you worked so hard on the first time down the track.

      Definitely a bummer.

      Seth
      200 mph or bust.......

      Comment

      • #4
        Re: But not as alive as I thought

        sounds like a signal problem, could be too much intake for the motor, or too much carb, doubt that though. You can make the secondaries open, just pull the spring out. The back fire could have toasted the power valve. The backfire is the dizzy, not the carb. Oh and the carb could be fuct too. Bring the car anyways, with tools, let me mess with it. You never know... Get a header gasket.

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        • #5
          Re: But not as alive as I thought

          Escaped on a technicality.

          Comment

          • #6
            Re: But not as alive as I thought

            I hate to impose on you, but if you're willing I can do that. It's on the trailer, so I'll just leave it there and drag it along. I have several manifold gaskets (it's one big long gasket with both intake and exhaust ports), a bag of tools, and a tube of high temp RTV. Anything else? Should I pick up a box of Holley jets, or can you bring yours? Wayne also suggested that I get a secondary plate with changeable jets. Do you have one to sell me? If not, could you pick one up and I'll pay you at the track? (The "speed shops" here have scoot). This is a hell of an offer, and I deeply appreciate it. Looks like I'm buying you dinner on Saturday, and not at Wendy's, either.

            Should I bring the Clifford intake and the 4BBL plate? It's much less radical than the manifold that's on there.

            Dan

            Originally posted by Green Junk
            sounds like a signal problem, could be too much intake for the motor, or too much carb, doubt that though. You can make the secondaries open, just pull the spring out. The back fire could have toasted the power valve. The backfire is the dizzy, not the carb. Oh and the carb could be fuct too. Bring the car anyways, with tools, let me mess with it. You never know... Get a header gasket.

            Comment

            • #7
              Re: But not as alive as I thought

              If the advance isn't repeatable then most likely the breaker plate is bad (loose at the pivot) or sticking. Either way it doesn't matter because you don't need it to move-run a screw through it to lock it down. The advance weights can cause the same problem, and have the same solution. If it were me I would be bringing a BIGGER carb along with me. Keep the RTV away from the intake ports-it will absorb gasoline and swell up into the port.

              Comment

              • #8
                Re: But not as alive as I thought

                Originally posted by DanStokes
                I hate to impose on you, but if you're willing I can do that. It's on the trailer, so I'll just leave it there and drag it along. I have several manifold gaskets (it's one big long gasket with both intake and exhaust ports), a bag of tools, and a tube of high temp RTV. Anything else? Should I pick up a box of Holley jets, or can you bring yours? Wayne also suggested that I get a secondary plate with changeable jets. Do you have one to sell me? If not, could you pick one up and I'll pay you at the track? (The "speed shops" here have scoot). This is a hell of an offer, and I deeply appreciate it. Looks like I'm buying you dinner on Saturday, and not at Wendy's, either.

                Should I bring the Clifford intake and the 4BBL plate? It's much less radical than the manifold that's on there.

                Dan

                Originally posted by Green Junk
                sounds like a signal problem, could be too much intake for the motor, or too much carb, doubt that though. You can make the secondaries open, just pull the spring out. The back fire could have toasted the power valve. The backfire is the dizzy, not the carb. Oh and the carb could be fuct too. Bring the car anyways, with tools, let me mess with it. You never know... Get a header gasket.
                Id bring both intakes Dan.

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                • #9
                  Re: But not as alive as I thought

                  Bummer. I was waiting to hear you made 300 hp with that thing.
                  1967 Chevelle 300 2 Door Post. No factory options. 250 ci inline six with lump-ported head, big valves, Offy intake and 500cfm Edelbrock carb.

                  Comment

                  • #10
                    Re: But not as alive as I thought

                    Dan - if it's an off the shelf holley 600 it sounds like possibly the metering block is faulty on the primary side or possibly the wrong metering block gasket was used.

                    Something is not allowing the flow of fuel to the main jets - and the backfires surely killed the powervalve unless a preventer was put in.

                    A carb swap should tell you quickly the story of how the engine should run -- borrow a known good one.

                    As far as the distributor - for sure check the point plate, and make sure the grounds are good.
                    There's always something new to learn.

                    Comment

                    • #11
                      Re: But not as alive as I thought

                      Just got back from Maxton. I took the car and Green Junk (Dave Maty) and his bro, Mike (miketblsr) look it over and offered several suggestions. Main one - the carb just isn't getting enough signal. The possible remedy - go to a 4 hole spacer. I'm currently using the open spacer I made out of pheonolic, and it's sitting on top of a huge plenum. No delta P means no signal to he carb - makes sense. Thanks guys!!! Keith also has some suggestions - primarily to shorten the fuel lines, as well as some additional safety stuff (minor, but needs doing). Thanks to Keith, too. So I'll have plenty to keep me busy.

                      Mary Ellen and I are heading to Michigan tomorrow and will be gone for 3 weeks, so I may not get to work on it much between now and the June meet, so I may not get down the track 'till September. All in all, it'll be what it is.

                      So thanks for all the help, all

                      Dan

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                      • #12
                        Re: But not as alive as I thought

                        Might want to check the Radiator hose clamps for tightness also ;)

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                        • #13
                          Re: But not as alive as I thought

                          Dan, if you and ME are in the Livonia or Birmingham area, give me a call. Maybe I can give you a little tour of our shop or maybe some lunch. 586-612-2373

                          Cognizant Dissident

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