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Camshaft failure

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  • Engine: Camshaft failure

    Well fellows (and gals) the old lube oil gremlin finally got me! I have a full flow block, supercharged 289 that has just wiped out the first lobe on the left bank. The exh valve on the no. 1 cylinder. Unbeknownst to me when I bought this car the engine had been converted to the hydraulic lifters. It has cut down rocker shaft towers, Chevy vales and springs etc. SO I'm stuck with the hydraulics unless I elect to completely convert back to solid lifters. Eg. cylinder heads, valves, springs, rockers, pushrods, cam and lifters A NEW ENGINE ALMOST. Interesting also is that I've always run ZDDP AND STP with every oil change. That's what makes this a strange event is that I took every precaution and the gremlin got me anyway.
    Discussion: Has anyone else had a similar experience?
    I am not fond of the hydraulic conversion as it gives low vacuum and low compression. I had a customer with hard starting complaints and I found he had very low compression and 8 in hg vacuum when idling. Converted back to R2 cam and solid lifters and the engine came back to life.
    Discussion: Any other similar experiences?

  • #2
    No experience, but just curious about the cam profile, and the open & closed pressure of the Chevy valve springs you mentioned. The Stude cam mild ramps, and the springs are little than a riding lawnmower, i.e. around 95 PSI closed. If the Chevy springs are significantly higher, it may be worth addressing while you fixing it. As for putting it back to stock, since you're going to be swapping the cam anyway, all you will need is another set of heads and rockers. Yes? No?

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    • #3
      Was the cam ground with a hydraulic profile? Just dropping the parts, spec'ing a lift and duration, and making them fit is not the total solution. Solid lifters don't use the same ramp rates as hydraulic.
      Jim
      Often in error, never in doubt
      http://rabidsnailracing.blogspot.com/

      ____1966 Avanti II RQA 0088_______________1963 Avanti R2 63R3152____________http://rabidsnailracing.blogspot.com/

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      • #4
        Curious that only one lobe has failed. Makes me suspect components related to that one lifter, rod, and rocker. If the rest of the cam looked OK, I doubt that lubrication would be an issue. How does the rest of the cam look?
        John Clary
        Greer, SC

        SDC member since 1975

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        • #5
          Most of the failures I have seen in Stude engines are on the #1 or 2 cylinder. Be it rod bearings or camshaft. Could be a supply problem.

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          • #6
            Chevy springs in a Stude head...that's pretty difficult since the sbChevy springs are too short, and the bbChevy springs are too large a diameter. Cut this, trimmed that...!? Even the valve swap is more expensive than just buying Stude valves from a Stude vendor.

            Sounds like others have mentioned, just a part failure because of possibly not being a good/proper match with each other..
            You don't "need" to change anything on the heads, rockers if the swap was done correctly..!?

            Mike

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            • #7
              By the By

              Any body need some heads from a 62 259 NFF with a 3 spd overdrive.?????????????????????Actually, I have the complete schmear stored at my home in Weirton Wv. just 35 miles east of pgh pa. Engine, bell housing, clutch and tranny, all buttoned up. Been sitting inside my garage on a molested shopping cart. I would like it to go to someone that could appreciate it for a CASO price. I gotta good deal, you need it, you're gonna get a better deal . Shopping cart bottom frame goes with it for no additional fee. cheers jimmijim. Ya gotta pick it up. Ran when pulled from a 56 Ford pickup. I plan on being there from Monday till Wednesday of next week and then on to the York swap meet some 250 miles away. Call if ya need it. I'm sure we can work something out. I'll leave this post up unless someone buys it. Otherwise, if you see this post the drive train is available. If I have to tote this to York, it will cost an xtra 150.00 Plus what we agree on, but must be more than the price of scrap. thanks I aint Lion. 334 792 4323 cell no. 304 374 6131 cheers jimmijim
              Originally posted by Mike Van Veghten View Post
              Chevy springs in a Stude head...that's pretty difficult since the sbChevy springs are too short, and the bbChevy springs are too large a diameter. Cut this, trimmed that...!? Even the valve swap is more expensive than just buying Stude valves from a Stude vendor.

              Sounds like others have mentioned, just a part failure because of possibly not being a good/proper match with each other..
              You don't "need" to change anything on the heads, rockers if the swap was done correctly..!?

              Mike
              Last edited by jimmijim8; 02-21-2012, 08:54 AM.
              sigpicAnything worth doing deserves your best shot. Do it right the first time. When you're done you will know it. { I'm just the guy who thinks he knows everything, my buddy is the guy who knows everything.} cheers jimmijim*****SDC***** member

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              • #8
                Without knowing exactly what parts mashup you've got in there, it's impossible to give an exact recommendation. However, just know many are running the Chevy valves and springs with cut down rocker shaft stands. Nothing on the heads have to be changed for you to go back to a solid lifter cam.

                jack vines
                PackardV8

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                • #9
                  Jimmijim, PM sent
                  Jamie McLeod
                  Hope Mills, NC

                  1963 Lark "Ugly Betty"
                  1958 Commander "Christine"
                  1964 Wagonaire "Louise"
                  1955 Commander Sedan
                  1964 Champ
                  1960 Lark

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                  • #10
                    Thanks for all the discussion:
                    Joe H. Since the cam was in the engine when I bought the car, I don't know anything about the profile. HOwever, From all the other abortions I've seen in this vehicle I would expect the worst.
                    JClary. All the other lobes appeared(visually) OK. All lifters were flat to very slightly concave what I would condiser normal for a broke-in engine.
                    Allan, The Oil pressure has always run very high, 80 PSI at highway cruise. I believe it's a gauge problem as I checked the relief valve, and it was A OK.
                    Mike Van V. No it's a mod that includes cutting 1/4 inch off the complete height of the valve train. The SBC valve are 1/4 inch shorter so to keep the geometry nearly correct one must cut off the towers and the pushrods to matec the new height of the valves when their fitted into the heads.

                    To convert back to solid lifters I believe I only need to re-calibrate pushrod length. Since the new solid lifters would be shorter, the pushrods would need to be lengthened(from the ones used with the SBC valves) but OEM Stude pushrods would probably be too long. Have not really reviewed this yet.

                    Thanks for all the feedback, you've triggered my thought processes.

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                    • #11
                      All lifters were flat to very slightly concave what I would condiser normal for a broke-in engine.
                      FWIW, a lifter which is flat across the bottom is half-way to failure. A concave lifter has already failed. Good lifters should show a definite convex radius when checked with a machist's square.

                      jack vines
                      PackardV8

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