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  • Engine: Valve adjustement

    I've had my 56 PowerHawk (259) maybe 3 months and have been planning to adjust my valves with a buddy who has a 56 Commander, but we haven't been able to schedule time yet. My question is, since I don't know when it was last done, is there any way to tell when its time? Do they tend to wear loose and make noise? Or tend to wear tight and burn valves?
    I may be doing a 700 mile trip in a few weeks.
    Thanks,
    Rafe
    Pointless insane picture attached for your viewing shock.
    Attached Files

  • #2
    The clearance tends to diminish as the valves hammer into their seats, and the exhaust valves hammer in about 10 times as fast as the intakes. If there is a light tick, that's good. If the engine is silent, it may still be OK, as long as it idles smoothly. When valves begin to close up, the first thing to deteriorate is the smooth idle, it will progress into more a rocking, that can sometimes be felt, i.e. if sitting at a red light.

    Once adjusted properly, they should not need readjustment for at least 10,000 miles. If in doubt, i.e. the car's maintenance history is unknown, I'd adjust them. Do not try to adjust them with the motor running, as the Shop Manual suggests. Use the archives here to look up some of the many articles written on the subject. If unsure what kinda valve cover gaskets are on the car (rubber or cork), or when they were last changed, I'd have a new pair of gaskets on hand before beginning the job. Most of them come with new rubber seals also, which go onto the bolts that hold the covers in place. It's a good idea to replace those when the valve cover gaskets need replaced.

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    • #3
      Thanks Joe. I already have gaskets and seals and have read up on adjustment. I'm good with motorcycles and those with rockers tend to wear loose, those with cam over valve tend to wear tight. My idle seems fine, but I will make every effort to get it done before my trip. My motor is said to have bigger valves, aftermarket cam, and Cadillac valve springs, so probably even more urgent that I check them. Previous owner revved it to 5500rpm at drag strip, says it ran in the 15s at 90mph. If true, how does that compare to stock?

      Rafe

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      • #4
        If my buddy does drive up with his Commander, how long does it take before his motor is cold? I've run a garden hose over air cooled MCs to cool them, but the 259 block has a lot of thermal mass.
        Rafe

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        • #5
          When I plan on a rocker adjustment, I let the engine sit "overnight". Then head out in the morning and go to work.
          Remember, just because the rocker cover is cool, or the intake manifold is cool, it takes a lot longer for the interior parts fo be fully cool.

          If the engine has hard exhaust seats and good valves, you should be able to go 12,000 to 15,000 miles between adjustments.
          But...without hard seats, you'll end up adjusting the exhaust three to one vs the intake. Like Joe says, without the lead in the gas, the hot exhaust valves and seats take a beating. The intake calves are cooled slightly during every intake stroke, so they don't take the hot beatings like the exhaust.
          BUT, all that said, a lot of this depends on how you drive the car. I drove my 259 powered Lark every day, as a regular car. 65 to 75 on the freeway, around town is also hard on an engine.
          So you'll have to come up with your own adjustment schedule, dependant on your driving.

          I checked my adjustment about every 7000 miles. Mostly always, the exhaust needed adjusting, and the intake did not. Like I said, about 3 to 1. That is, three exhaust rocker adjustments to one intake adjustment.

          Also like Joe says, when the idle gets a "little" rough...you've waited too long..!

          Mike

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          • #6
            Go to video #34 in the sticky above on rebuilding the Studebaker engine. It covers valve adjustment.

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            • #7
              The Manual (if memory is OK) states engine to be at 70 deg F after sitting (non running) for 8 hrs - It is in the Repair Manual. Also (as above) set valve lash cold (add .002" to the hot settings). Also there are easier processes to perform the adjustment than shown in the manual - Do a "search" for "valve adjust".
              Take plenty of time - Not a job you want to mess up.
              paulk

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              • #8
                When I adjust valve lash on motorcycles, instead of finding the one or two crank shaft places where most can be adjusted, I do this: Turn motor around till a valve closes, then a half rev more. This makes sure that valve is closed and the lobe is more or less opposite the pushrod. It takes a bit more turning of the crank, but then I can go in order with out keeping a chart.
                Will this work on a V8? What other ways are there?
                Thabks,
                Rafe

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                • #9
                  You can do it just like a small Chevy, same sequence. With #1 at TDC adjust exhaust - #1, #3, #4, #8 and intake - #1, #2, #5, #7
                  Rotate engine 360 degrees to #6 TDC and adjust exhaust - #2, #5, #6, #7
                  intake - #3, #4, #6, #8


                  But any way you want to do it will work as long as the valve is completely closed.


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                  • #10
                    Originally posted by bensherb View Post
                    But any way you want to do it will work as long as the valve is completely closed.
                    That's the important part - making sure the valve is completely closed.
                    RadioRoy, specializing in AM/FM conversions with auxiliary inputs for iPod/satellite/CD player. In the old car radio business since 1985.

                    17A-S2 - 50 Commander convertible
                    10G-C1 - 51 Champion starlight coupe
                    10G-Q4 - 51 Champion business coupe
                    4H-K5 - 53 Commander starliner hardtop
                    5H-D5 - 54 Commander Conestoga wagon
                    56B-D4 - 56 Commander station wagon
                    60V-L6 - 60 Lark convertible

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                    • #11
                      Got it done! Smoother idle. All valves were way too tight, many less than .01" but all had some clearance (at least when cold). I did a compression check before and after. Most cylinders were 175-180 psi. Two were 145 & 150. After valve adjust, the 145 came up to 165. The 150 stayed the same, but it may have been because it was the last one I checked and my battery wasn't spinning it fast enough.
                      Before lash adjust, motor was silky quiet, but when warm the idle was a bit rough. Now have excellent idle, but I can hear the engine... a very faint sound sorta VW bug/sewing machine sound. No ticking tho.
                      I also found and fixed a gas leak on fuel line at carb. And I think I also fixed leaky valve cover gasket... so maybe it might smell better?
                      So satisfying doing this stuff, getting more confident about my 800 mile round trip from NorCal to Salem, Oregon.
                      Thanks,
                      Rafe
                      Attached Files

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                      • #12
                        Congrats on a job well done!!! Good luck on your trip and enjoy the Stude! Luck Doofus

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