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  • Engine: Ca Lobe Measurement

    If my math is correct, the lobes on a stock 259/29 camshaft should measure .239-.240". Can anyone verify this to be correct? I have a 289 in a machine shop, and in order to check the cam, they need the specs. My Stude Shop Manuals only provide cam timing, and not profile.

    Can anyone verify my math above, as to lobe measurements?

    Thanks,
    Joe

  • #2
    Joe -

    If they are doing the assembly, they need the "actual cam" to verify the cam timing /installation. For just machining the block, they don't need anything
    Any other "measured numbers" (as in hard part dimensions) are basically usless to them, and unless you buy one of the gears I'm having made, it'll be costly to change the existing cam timing. What they are doing is to verify the installation degrees of the intake lobe to the crankshaft.
    And actually...without the "actual" old Studebaker cam information, the cam installation angle is only a guess.


    Below is my comment from the gear thread...fits here too -

    On one hand, just because they do mostly Chevy stuff...doesn't mean they can't do a good job on the Stude engine too.
    Think about it...how many Stude engines are there being rebuilt..!

    On the other hand, if they've never done a Stude engine....YES...they need to know the coupla qurks that the Stude has...like having the timing gears and no chain. Remember where the crank thrust shims go..."you" need to remember to reinstall the pipe plug in the distributer cavity in the block, maybe the proper installation method of the wrist pin pinch bolts in the rods. Some of those things.

    Otherwise, it's just an engine, it requires the same things to make it work as other engines.

    Mike

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    • #3
      Looks like you used the 23/64" valve lift, and assumed a 1.5 rocker arm ratio? I got 0.240" too.

      I still get a kick out of metric dimensions included right beside the inch dimensions as standard in the Studebaker Shop manual. I guess it means they took their export sales pretty seriously.

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      • #4
        I went back to the shop and picked up the cam today top sheck it myself. The lobes are measuring .248-.250". Don't know what happened with the math, but Dan you are correct as to how I calculated it.

        I would never allow a shop to assemble a Stude engine. I disassemble it, take the components to the shop for inspection and machine work I cannot perform, then reassemble it myself. That has been the way I did it for 5 or 6 Stude V8s now since 1985. I believe there are just too many quirks in a Stude V8 to entrust it to a shop that specializes in modern stuff.

        The worse horror story I have heard lately happened at a well reputed machine shop in Louisville, KY. They rebuilt a guy's Sky Hawk 289 and left the pressure relief valve in it when they baked it and hot tanked it. It was besically welded into the block. I don't know how they ever got it out, but eventually they did. I knew the guy who ran that shop well, and he was as good an engine rebuilder as they come. He was just out of his turf with the Stude V8. I would have taken this block to him for the machinist work, but he is now deceased.

        Thanks everyone for your helpful info & advice.
        Joe

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        • #5
          Originally posted by JoeHall View Post
          I went back to the shop and picked up the cam today top sheck it myself. The lobes are measuring .248-.250". Don't know what happened with the math, but Dan you are correct as to how I calculated it./Cut/
          So could that mean that you stumbled apon an R1/R2 Camshaft?

          StudeRich
          Second Generation Stude Driver,
          Proud '54 Starliner Owner
          SDC Member Since 1967

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          • #6
            I dunno Rich,
            According to the Shop Manual, the lift is same for standard 259/289 and the R1/2. It looks like the difference is in duration. If it is an R cam I will not run it.
            Joe

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            • #7
              Originally posted by JoeHall View Post
              I dunno Rich,
              According to the Shop Manual, the lift is same for standard 259/289 and the R1/2. It looks like the difference is in duration. If it is an R cam I will not run it.
              Joe
              Curious, I'm in the middle of a tear down on my 57 Goldie. I'm just starting to look at cam choices. What have you experienced with the R cam? Sounds like you don't like it.
              My first car on the road again!

              The old girl has never been sold to the public
              Grandpa was a Studie dealer. He got it off the car carrier in 1956 and drove it until 1959
              My dad: 1959-70

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              Me: 1970-2015 and counting!

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              • #8
                I have zero experience with R cams. This woulda been a good time to gain some, but I stayed OEM for several reasons: woulda needed new, stiffer, R type springs (the OEMs checked out fine); the stiffer springs woulda called for a new aluminum timing gear (the repros are reputed to whine, besides, already had an NOS fiber one); woulda needed to change final drive ratios to spin the engine faster at road speeds, to realize advantage of the hotter cam (currently have 3.54 w/OD); it would likely use more gasoline (I'm a self confessed CASO), and the life expecatncy of the heads would be less.

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                • #9
                  As usual, Joe has done his homework. I'd add using an R1/R2 cam in a standard 8.5 compression engine results in some loss of low end torque.

                  jack vines
                  PackardV8

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