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Worn out 289 with sticking intake valve??

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  • Worn out 289 with sticking intake valve??

    I have an Avanti R2 with recently rebuit AFB carburetor with new leaner metering rods & jets, new coil, plugs, plug wires, original Prestolite distributor OK as far as centrifugal advance weights and vacuum advance, on a 98,000 mile untouched original 289. I rebuilt the fuel pump a few years ago and think it works OK. My local Montana mechanic tells me that it has a sticking intake valve on cylinder #6 which causes it to backfire through the carburetor and stall. It will run fine on an idle, but will backfire or stall when put in drive or under a load. Held on a fast idle (2000 rpm) it will fluctuate regularly in speed down to 1500 up to 2000. It is virtually undriveable as it is, although it can slowly be teased up to speed at the risk of being stranded. It also has a tendency to flood after stalling. I could try to further lean out the idle screws, but I wish I knew where I could get better advice. I also have a home in SoCal and used to take it to Jon & Mike Meyers when it was newer, but hope to get the problem resolved without hauling the car to CA or OH. Where can I get the 289 rebuilt? Does anyone have any advice on how to procede further? I will be in Omaha for the meet on the 26th.

  • #2
    I'm far from the expert others on this forum are, but I can't imagine one sticking valve making a car undriveable. Let's see what the experts have to say. Sounds like carb issues--but again we need the experts. Rebuilding AFBs "ain't" rocket science. If it tends to hunt up and down in rpm it might already be too lean.

    wagone

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    • #3
      Check yhe metering rod springs. If they are too strong you don't have enough vacuum to pull the rods down at low RPM.


      Studebaker On The Net
      http://stude.com
      Studebaker News Group
      http://groups.google.com/group/alt.autos.studebaker
      Arnold Md.
      65 Sports Sedan(sold)
      64 Daytona HT
      63 R2 4 speed GT Hawk
      63 GT Hawk
      63 Avanti R1/AC
      63 Avanti R2/4 speed
      63 Daytona HT
      63 Lark 2 dr.
      62 Lark 2 door
      62 GT(parts car)
      60 Lark convert
      60 Hawk
      52 Starliner(sold)
      51 Commander
      JDP Maryland

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      • #4
        I'm having trouble with the "sticking valve" thing too. Too what degree did this guy tear into this engine to make such a determination?
        Was it running OK before all this work was done to it or has it been setting for sime time prior to this?[}]

        Miscreant adrift in
        the BerStuda Triangle!!

        1957 Transtar 1/2ton
        1960 Larkvertible V8
        1958 Provincial wagon
        1953 Commander coupe
        No deceptive flags to prove I'm patriotic - no biblical BS to impress - just ME and Studebakers - as it should be.

        Comment


        • #5
          My thoughts were around the Carb becuase rebuilders often use too strong a spring for the low vaccum on a R2.


          Studebaker On The Net
          http://stude.com
          Studebaker News Group
          http://groups.google.com/group/alt.autos.studebaker
          Arnold Md.
          65 Sports Sedan(sold)
          64 Daytona HT
          63 R2 4 speed GT Hawk
          63 GT Hawk
          63 Avanti R1/AC
          63 Avanti R2/4 speed
          63 Daytona HT
          63 Lark 2 dr.
          62 Lark 2 door
          62 GT(parts car)
          60 Lark convert
          60 Hawk
          52 Starliner(sold)
          51 Commander
          JDP Maryland

          Comment


          • #6
            From the "flooding" & "tease it up to speed" parts of the statement...my bet would be in the carburetor and or timing (distributor problem in general) also.

            A "stuck" valve would cause all kinds of racket (noise), it would run like crap at all rpm's, and would NOT cause a carburetor to flood over!! Wouldn't idle hardly at all.

            Back fire, yea....but all the time, not just when trying to rev it.

            You did say one thing correct....find a better machanic!!

            Mike

            Comment


            • #7


              "New leaner metering rods & jets???!!... popping from carb??!!! " I'll bet that what you're experiencing, is detonation, from too lean a mixture. How did this "mechanic" determine you needed a leaner carb, on an R2? If anything, the jets and rods should have been replaced with the original sizes. This engine is designed to run rich, to compensate for the blower pressure and fuel demand.
              The flooding is being caused by the fuel pressure boost with blower pressure. You have to tease the RPM up, because the mixture is too lean. Backfiring starts to occur, when your spark advance get near peak and preignition fires the mixture...
              Tell the "mechanic" to RTFM and hope you didn't burn a hole in a piston
              64 GT Hawk (K7)
              1970 Avanti (R3)

              Comment


              • #8
                55prez said -
                quote:This engine is designed to run rich, to compensate for the blower pressure and fuel demand.
                Where did you come up with that one?

                Please enlighten me/all of us, how a Studebaker (any engine for that matter) can be designed to run rich?

                Carbureted, mechanical fuel injection, electronic fuel injection, belt driven or gas driven blower, nitrous oxide all have their differeing fuel expectations.
                It ALL goes to the amount of air going into the cylindres.
                A blown engine and nitrous oxide injected will need a little more fuel because of the extra air being forced into the engine. That does NOT mean they are running rich.
                Any fuel (gasoline, nitromethane, alcohol, nitrous) needs it's own particular amount of air to run right.

                Rich is rich in any combination. The best power will NOT be gained, the best milage will not be gained, oil milage and spark plug milage will also suffer.

                Just a suggestion...if you've got your engine tuned rich...you might try leaning it down a bit.

                Now...if you mean with a supercharged engine, you need more fuel...you are correct (see above). But the "rich" statement does not work correctly.

                Mike

                Comment


                • #9
                  "Please enlighten me/all of us, how a Studebaker (any engine for that matter) can be designed to run rich? "

                  Here's your enlightenment...

                  You ever check the jet sizes on an R2 vs an R1 ... or a 57 GH Ww carb vs a standard 2 bbl.

                  The overjetting was established to have the engine run properly when the boost comes in. Failing to run a richer mixture, than a normally aspirated engine, will result in detonation, because the ratio would be too LEAN* It doesn't happen magically, it has to be there, so the mixture is statically richer on an R2, than it is, on an R1.

                  >>>"Now...if you mean with a supercharged engine, you need more fuel*."<<<

                  *I think this equates to running richer. Could you enlighten us, as to where the "more fuel" is going to come from, in this instance?
                  64 GT Hawk (K7)
                  1970 Avanti (R3)

                  Comment


                  • #10
                    Thanks guys for the advice. I do need a new mechanic, as this one here in Anaconda, MT (population 7,500) is stumped. Part of my problem is than few in this town know anything about Avantis. He did RTFM which I provided. I doubted his diagnosis as he did not check compression in cylinders. Problem started because of "backfiring" and killing, with carb as originally equipped, which led to checking distributor centrifugal and vacuum advance, followed by new coil and plug wires (didn't change dual points) and tuning to specifications for R2 (18 degrees before TDC @ 1800 rpm). Mechanic said distributor was "only getting 1/2 voltage". This apparently was fixed.

                    Talked to Jon Meyer, and after a lengthy discussion where he was skeptical about changing jets & rods, which I had bent in my rebuild of carburetor, I decided to try leaning down mixture with leaner jet and metering rods, using original springs, because of the persistent flooding and fouling of plugs. I guess the engine is "leaned to the max" and it usually starts and idles OK now, but problem is running at speed. I will try the advice you have given me to make it run richer.

                    BTW, the problem persists even with supercharger disconnected from carb. I will do one thing at a time, then possibly try setting timing back a little. I do have an R1 which runs OK, I could try swapping carbs for diagnotic purposes. I did have a problem with fuel line blockage near the tank but that was fixed earlier by John Metzger in CA. Thanks for advice so far.

                    Comment


                    • #11
                      quote:Originally posted by Studebaker Johnny
                      Mechanic said distributor was "only getting 1/2 voltage". This apparently was fixed.
                      It's supposed to get 1/2 voltage...approximately 6 volts. There is a resistor in line to the coil to drop the voltage. If he bypassed this resistor it will burn out the coil and/or points rather quickly.



                      Dick Steinkamp
                      Bellingham, WA

                      Comment


                      • #12
                        So many possibilities here.......is it hard to start cold? When you try to open the throttle from an idle it spits back through the carburetor and dies? That's typical of an inoperative accelerator pump in the carburetor.
                        Or is this a more rapid and less severe 'popping' as the rpm is raised, and that has been traced somehow to number 6 cylinder? That could be a broken valve spring.


                        Dwain G.

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                        • #13
                          I replaced the accelerator pump myself from a kit from SI. It appears both to me and the mechanic (visually) to work correctly. The ballast resistor is hooked up right to deliver only reduced voltage to the coil and points. It does seem to "spit" back through the carburetor when opening the throttle, especially when in gear. I can get it to drive only with a very light foot on the gas pedal.

                          Comment


                          • #14
                            []Fortunately I have two Avantis, a 64 R1 and the said 63 R2, both high mileage original engine cars. Taking advice from this forum into account, I felt the problem was fuel/mixture/carburetion, so I swapped carburetors yesterday. Then, with one quart of Risolone added to the oil, I ran it at 2000 rpm for an hour. If the intake valve ever was stuck, that seemed to unstick it. Viola! Problem mostly solved. Said R2 is now drivable, both with and without supercharger attached, and it does not drive badly. The problem was switched with the AFB to the R1, which at least runs better than the R2 did. I will pull the "bad" AFB and work on it, to find out the problem. It could be the wrong metering rods & jets, or the springs on the metering rod pistons, or possibly the accelerator pump. But not until after the trip to Omaha (in a Cadillac). Someday I may be able to have a car in such shape to present at an International Meet. (sigh)

                            46 M-5
                            48 Champ Starlight
                            56 Sky Hawk
                            63 R2
                            64 R1
                            64 Cruiser

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                            • #15
                              Only my opinion, of course - but if it runs it's in shape to take to an international meet. I reckon a running Stude beats a non-runner any day. Go for it and enjoy the ride.
                              /H

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