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Cam for 55 56?

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  • Stuart F.
    Expired
    • August 31, 1996
    • 4676

    #31
    Re: Cam for 55 56?

    Clem;

    I worked for the former GM Locomotive division as a Senior Technical Writer for 22+ years and worked closely with many of the young GMI Engineers there. The smart ones would come to me and ask questions about the old 645 and 710 engines. The others chose to "re-invent the wheel" all the time. They were too smart for their own good (big egos) and it was "de ja vu" all the time. They were incurring the same problems that we had addressed and solved years before. Sure, we tried to contact them and explain that the problem had occurred and been resolved before, and would even give them specific references to change notices or instructions, etc., but often times the attitude was; "What do you know old timer". They would go on muddling through wasting time until they essentially solved a problem that had been solved before. It happened time and time again until I learned to keep my mouth shut until and if they seeked me out for advice. Those are the ones that made it to the top.

    Stu Fox

    Comment

    • Clem Z.
      Expired
      • January 1, 2006
      • 9427

      #32
      Re: Cam for 55 56?

      Originally posted by Tyler Townsley (4814)
      Back to my question, would not connecting the oil holes in the bearing accomplish the same thing without having to do any machining in the block?

      Tyler
      yes it would but notching the block would allow you to use a late model bearing which would be easier to find and less chance of a screw up on which bearing to use

      Comment

      • Edward M.
        Extremely Frequent Poster
        • November 1, 1985
        • 1916

        #33
        Re: Cam for 55 56?

        Originally posted by Tyler Townsley (4814)
        Back to my question, would not connecting the oil holes in the bearing accomplish the same thing without having to do any machining in the block?

        Tyler
        Yes, elongating the hole would eliminate the need for the two hole cam bearing, but wouldn't you would still need the camshaft with the flat groove in it? Machining the block eliminates the need to use that cam as well.
        Last edited by Edward M.; September 28, 2008, 06:30 AM.

        Comment

        • Tyler T.
          Expired
          • August 31, 1981
          • 282

          #34
          Re: Cam for 55 56?

          Originally posted by Edward McComas (9316)
          Yes, elongating the hole would eliminate the need for the two hole cam bearing, but wouldn't you would still need the camshaft with the flat groove in it? Machining the block eliminates the need to use that cam as well.
          John Neas called and told me Tom Parson did the bearing mod on his 56 265. Uses a later non grove cam and they have had no oiling problems. I doubt my engine will ever be removed much less taken apart in the future so getting it right this time should suffice. Thanks to all for the input. Hopefully this thread will help those who have this challange in the future.

          Tyler

          Comment

          • Edward M.
            Extremely Frequent Poster
            • November 1, 1985
            • 1916

            #35
            Re: Cam for 55 56?

            Originally posted by Tyler Townsley (4814)
            John Neas called and told me Tom Parson did the bearing mod on his 56 265. Uses a later non grove cam and they have had no oiling problems. I doubt my engine will ever be removed much less taken apart in the future so getting it right this time should suffice. Thanks to all for the input. Hopefully this thread will help those who have this challange in the future.

            Tyler
            Tyler,

            I think you would still need a camshaft with the grove cut into it. John Hinckley seems to agree. I asked this very question over on the CorvetteForum, and John replied that the grooved camshaft was still needed. The block mod I described earlier is the only way I am aware of that would allow someone to use a non grooved camshaft.

            I just pulled the engine out of my 56 because of the no oil to heads issue. Haven't had a chance to pull the engine apart yet.

            Need to get this issue finalized so I can figure out how best to solve the problem.

            Aren't these old cars fun?

            Comment

            • Clem Z.
              Expired
              • January 1, 2006
              • 9427

              #36
              Re: Cam for 55 56?

              Originally posted by Edward McComas (9316)
              Tyler,

              I think you would still need a camshaft with the grove cut into it. John Hinckley seems to agree. I asked this very question over on the CorvetteForum, and John replied that the grooved camshaft was still needed. The block mod I described earlier is the only way I am aware of that would allow someone to use a non grooved camshaft.

              I just pulled the engine out of my 56 because of the no oil to heads issue. Haven't had a chance to pull the engine apart yet.

              Need to get this issue finalized so I can figure out how best to solve the problem.

              Aren't these old cars fun?
              you would not need the flat on the cam journal because the slotted bearing would allow continuous flow of oil from the drilled main oil gallery to the groove in the block behind the cam bearing and this would feed the lifter oil gallery. same a grooving the block in the same area but under the later model cam bearing without the slot in the bearing
              Last edited by Clem Z.; September 28, 2008, 04:06 PM.

              Comment

              • Edward M.
                Extremely Frequent Poster
                • November 1, 1985
                • 1916

                #37
                Re: Cam for 55 56?

                Clem,

                OK, I understand what you are saying. You are creating a continual path for the oil within the cam bearing. The block mod I mentioned earlier would create the continual oil path behind the cam bearing. Either should work.

                How much oil can get through that passage within the cam bearing. Enough for the top of the engine?

                John Hinckley, what do you think about this?

                When I get both John and Clem nodding in agreement, I know I can take that answer to the bank.

                Comment

                • Clem Z.
                  Expired
                  • January 1, 2006
                  • 9427

                  #38
                  Re: Cam for 55 56?

                  Originally posted by Edward McComas (9316)
                  Clem,

                  OK, I understand what you are saying. You are creating a continual path for the oil within the cam bearing. The block mod I mentioned earlier would create the continual oil path behind the cam bearing. Either should work.

                  How much oil can get through that passage within the cam bearing. Enough for the top of the engine?

                  John Hinckley, what do you think about this?

                  When I get both John and Clem nodding in agreement, I know I can take that answer to the bank.
                  you would need to make the groove as wide as the diameter of the main oil gallery and that should be enought oil flow for a solid lifter cam. a hyd cam i would groove the block because the volume of the passage would be larger

                  Comment

                  • Tom P.
                    Extremely Frequent Poster
                    • April 1, 1980
                    • 1814

                    #39
                    Re: Cam for 55 56?

                    This procedure to modify the rear cam bearing/oil passage is tooooooooooooooooo easy to do.
                    All you need is a Dremel Tool with a small rotary file (I use a carbide rotary file for more precise cutting). With the REAR cam bearing removed from the block, simply grind a groove between the groove (annulus as some like to call it) in the cam bearing bore and the oil passage hole. I made the groove the same width as the oil passage hole in John Neas' engine for his #7 1956 Sebring race car. I have NO CLUE how many hours are on that engine, but I guarantee there are MORE THAN ENOUGH hours to have caused a failure from poor oiling if this simple modification to a 265 block didn't work!!!!!!!
                    This modification to a 265 block will permit using ANY cam without the groove in the rear cam journal.
                    Actually, I DO NOT understand why Chevy didn't do this in the first place!!!!!!!! IT'S JUST TOOOOOOOOOOOOOO SIMPLE!!!!!
                    When I built this engine for John, he brought me the rolling chassis for his 58 big brake/FI car (which is presently undergoing a TOTAL restoration), along with a radiator, battery and 5gal gas can. I put the Sebring 265 engine in the 58 Chassis, fired it up, broke it in at about 2500rpm for quite some time, and then ran it multiple times after that. ZERO oiling problems.
                    So, we now have one "FOR SURE" engine that this simple modification prooves how well it works.
                    No, it never occured to me to take a picture of this groove that I cut in the rear cam bore, nor did it occur to me to make a short video of it.

                    Comment

                    • Clem Z.
                      Expired
                      • January 1, 2006
                      • 9427

                      #40
                      Re: Cam for 55 56?

                      if you have a engine that is all ready assembled slotting the bearing is the fastest way to do it as you can remove the rear cam bearing,have it slotted and reinstall it. to do the block you would have to disassemble the complete engine to so you could clean out the cast iron debris from the grinding of the groove in the block

                      Comment

                      • Tom P.
                        Extremely Frequent Poster
                        • April 1, 1980
                        • 1814

                        #41
                        Re: Cam for 55 56?

                        Originally posted by Clem Zahrobsky (45134)
                        if you have a engine that is all ready assembled slotting the bearing is the fastest way to do it as you can remove the rear cam bearing,have it slotted and reinstall it. to do the block you would have to disassemble the complete engine to so you could clean out the cast iron debris from the grinding of the groove in the block
                        And I agree with that 100%.
                        But I was only specifically referring to doing the mod prior to engine assembly, actually, prior to sending the engine out to the machine shop would be the most ideal time to do this.
                        I would not even want to do the bearing mod on a running engine, I'd prefer just to stay with the grooved cam until time to pull the engine and tear it down.

                        Comment

                        • Clem Z.
                          Expired
                          • January 1, 2006
                          • 9427

                          #42
                          Re: Cam for 55 56?

                          a other thing to check if the lack of oil to the top end is the problem is that the hole in the bearing line up with the oil feed hole in the block.

                          Comment

                          • Michael L.
                            Expired
                            • July 31, 2005
                            • 562

                            #43
                            Re: Cam for 55 56?

                            After all these mods are made and still no oil top, be patient, it can take a few minutes for all the lifters to oil. If still no oil, email me, I just went through this on my '55 265 V8.

                            Good luck,

                            Mike

                            Comment

                            • Clem Z.
                              Expired
                              • January 1, 2006
                              • 9427

                              #44
                              Re: Cam for 55 56?

                              to speed up the oil getting to the top end when using solid lifters fill them with oil from a squirt oil can thru the hole in the side of the lifters. DO NOT do this with hyd lifters as it could prevent you from setting the hyd lifter pre load.

                              Comment

                              • John H.
                                Beyond Control Poster
                                • December 1, 1997
                                • 16513

                                #45
                                Re: Cam for 55 56?

                                Originally posted by Edward McComas (9316)
                                Clem,

                                OK, I understand what you are saying. You are creating a continual path for the oil within the cam bearing. The block mod I mentioned earlier would create the continual oil path behind the cam bearing. Either should work.

                                How much oil can get through that passage within the cam bearing. Enough for the top of the engine?

                                John Hinckley, what do you think about this?

                                When I get both John and Clem nodding in agreement, I know I can take that answer to the bank.
                                Ed -

                                After noodling this again, I bow to Clem's expertise - only slotting the bearing to create a full-time oil passage from the main oil feed hole to the groove within the thickness of the bearing shell would appear to allow use of a cam without the flat on the rear journal. However, I'd prefer the block rework so the oil flow is direct to the groove, behind the bearing shell, without any concern for bearing hole alignment in the bore.

                                Photos below of the stock 265 rear bearing bore and oiling holes, and the stock 265 rear cam bearing.



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