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Cam for 55 56?

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

    #16
    Re: Cam for 55 56?

    OK I am totally confused now. I have a 55 265 .60 over at the machine shop right now. I had a link to an article online that discusssed removing the material on the cam bearing between the 2 holes(Making one elongated hole) and it stated 'with that mod' the notch was not necessary and later cams can be used. I have since crashed the my system and lost the link.

    I had told the shop to mod the bearing and go with a replacement cam. But based on what has been posted the notch is still necessary and one has to run the exact cam? Is that true? I intend to have the car flight judged in the future so I need to get it right now with the motor out of the car.

    Thanks.

    Tyler

    Comment

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

      #17
      Re: Cam for 55 56?

      Tyler,

      Check out these links, they have a lot of good info on the subject.

      Ed

      http://forums.corvetteforum.com/show...ight=heads+oil

      http://forums.corvetteforum.com/show...ight=heads+oil

      Comment

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

        #18
        Re: Cam for 55 56?

        Here's an excerpt from my "Tech Bench" column on 265 lifter oiling from the October '06 issue of "Corvette Enthusiast" magazine, in response to a reader's problem with no lifter oiling on a freshly-rebuilt 265 (which turned out to have a '57 cam with no notch AND the wrong rear cam bearing):













        Comment

        • William C.
          NCRS Past President
          • May 31, 1975
          • 6037

          #19
          Re: Cam for 55 56?

          If you purchase the correct reproduction cam from a reputable vendor as an exact duplicate of the 3711345 cam, it sould come with the notch, rendering a large part of this discussion and some extra expense for you for a questionable at the machine shop moot.
          Bill Clupper #618

          Comment

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

            #20
            Re: Cam for 55 56?

            if you want to use a non 55/56 cam in your 55/56 block and you can't find a machine shop do do the work just go to a industrial supply place and buy a 7/16" square file like shown below and carefully file the required notch.

            Comment

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

              #21
              Re: Cam for 55 56?

              John;

              A guy on the tri five web posted a reply that stated that you could machine the block by cutting a groove between the hole in the block and the groove that has the holes to the lifters. This would make a direct path between the oil holes on the underside of the cam bearing.

              This would allow you to use a single hole cam bearing and a cam that does not have a flat groove cut into it.
              Here are his comments:

              The modification consists of grinding a groove between the high pressure oil hole and the annulus
              machined in the block that feeds the lifter galleries. The groove needs to be made big enough to provide a sufficient
              supply of oil to the lifters. You can do this yourself or have your machine shop do it.

              Now you can install a standard rear cam bearing and use any standard small block cam and lifters in your 265.

              Make sense to you?

              Comment

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

                #22
                Re: Cam for 55 56?

                Originally posted by Edward McComas (9316)
                John;

                A guy on the tri five web posted a reply that stated that you could machine the block by cutting a groove between the hole in the block and the groove that has the holes to the lifters. This would make a direct path between the oil holes on the underside of the cam bearing.

                This would allow you to use a single hole cam bearing and a cam that does not have a flat groove cut into it.
                Here are his comments:

                The modification consists of grinding a groove between the high pressure oil hole and the annulus
                machined in the block that feeds the lifter galleries. The groove needs to be made big enough to provide a sufficient
                supply of oil to the lifters. You can do this yourself or have your machine shop do it.

                Now you can install a standard rear cam bearing and use any standard small block cam and lifters in your 265.

                Make sense to you?
                that is the way the later blocks oil the lifters by direct path from the main oil groove behind the cam bearing to the lifter galleries. post the tri five thread.

                Comment

                • Duke W.
                  Beyond Control Poster
                  • January 1, 1993
                  • 15610

                  #23
                  Re: Cam for 55 56?

                  If I understand the '55-'56 oiling system correctly, it means that the lifters and top end only received oil over about 30 degrees of cam rotation - when the notch allowed the feed hold from the main gallery to communicate directly with the outlet hole to the lifter galleries - strange!

                  Duke

                  Comment

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

                    #24
                    Re: Cam for 55 56?

                    Originally posted by Duke Williams (22045)
                    If I understand the '55-'56 oiling system correctly, it means that the lifters and top end only received oil over about 30 degrees of cam rotation - when the notch allowed the feed hold from the main gallery to communicate directly with the outlet hole to the lifter galleries - strange!

                    Duke
                    and they shot oil all over the place when you were ajusting the valves. i bought a set of rocker arm clips from john bandimere in denver colo. back in 1955

                    Comment

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

                      #25
                      Re: Cam for 55 56?

                      Clem;

                      I offered my set to Duke last week and he said "no thanks".

                      You haven't lived and bled Chevy blood until you've tried to adjust Chevy V8 valves with the engine running, with or without the clips. If the hot oil don't get you then the burning oil fumes will. Even in an open garage, you'll come away with a headache that will last a week.

                      I found my clips in my tool box last week and I noticed, even though they are "blued", they are rusting away. Good riddance. I only keep them to remind me about lessons learned from the old days - Don't even think about it!

                      Stu Fox

                      Comment

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

                        #26
                        Re: Cam for 55 56?

                        i used mine mostly to "zero" lash hyd lifters because to do it right you need to have the engine running.

                        Comment

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

                          #27
                          Re: Cam for 55 56?

                          Originally posted by Clem Zahrobsky (45134)
                          and they shot oil all over the place when you were ajusting the valves. i bought a set of rocker arm clips from john bandimere in denver colo. back in 1955
                          Here's the set I got from him in 1960 or so; still use them - they work much better than the modern-day spring-loaded junk the speed shops have.
                          Attached Files

                          Comment

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

                            #28
                            Re: Cam for 55 56?

                            Originally posted by Edward McComas (9316)
                            John;

                            A guy on the tri five web posted a reply that stated that you could machine the block by cutting a groove between the hole in the block and the groove that has the holes to the lifters. This would make a direct path between the oil holes on the underside of the cam bearing.

                            This would allow you to use a single hole cam bearing and a cam that does not have a flat groove cut into it.
                            Here are his comments:

                            The modification consists of grinding a groove between the high pressure oil hole and the annulus
                            machined in the block that feeds the lifter galleries. The groove needs to be made big enough to provide a sufficient
                            supply of oil to the lifters. You can do this yourself or have your machine shop do it.

                            Now you can install a standard rear cam bearing and use any standard small block cam and lifters in your 265.

                            Make sense to you?
                            Yes, it does; I hadn't thought about it, as I haven't worked on a 265 since the 60's.

                            The photos below (from the post on the Tri-Five site) show what he proposes. The one on the left is the rear cam bearing bore on a 265, showing the entry hole from the main oil gallery on the bore surface facing the cam journal; this only allows oil to get into the annulus groove in the bore that feeds the two lifter gallery holes once each cam revolution when the flat on the journal briefly creates a passage to the annulus groove.

                            The photo on the right is the '57-up rear cam bearing bore, showing the relocation of the main oil gallery feed hole to the annulus groove, which allows constant oil pressure to feed the two lifter gallery holes.

                            He suggests grinding away the bore surface locally between the 265 main oil gallery hole and the annulus groove, creating a full-time oil feed to the groove, and thus to the lifter galleries, so you can use a '57-up cam and rear cam bearing. Sounds like it would work OK.
                            Attached Files

                            Comment

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

                              #29
                              Re: Cam for 55 56?

                              i often wonder why the engine designers at chevy did the same thing on the first BBC in 1965 when they had the later SBC to model after. they must have not been around when the first SBC was designed.

                              Comment

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

                                #30
                                Re: Cam for 55 56?

                                Originally posted by John Hinckley (29964)
                                Yes, it does; I hadn't thought about it, as I haven't worked on a 265 since the 60's.

                                The photos below (from the post on the Tri-Five site) show what he proposes. The one on the left is the rear cam bearing bore on a 265, showing the entry hole from the main oil gallery on the bore surface facing the cam journal; this only allows oil to get into the annulus groove in the bore that feeds the two lifter gallery holes once each cam revolution when the flat on the journal briefly creates a passage to the annulus groove.

                                The photo on the right is the '57-up rear cam bearing bore, showing the relocation of the main oil gallery feed hole to the annulus groove, which allows constant oil pressure to feed the two lifter gallery holes.

                                He suggests grinding away the bore surface locally between the 265 main oil gallery hole and the annulus groove, creating a full-time oil feed to the groove, and thus to the lifter galleries, so you can use a '57-up cam and rear cam bearing. Sounds like it would work OK.
                                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

                                Comment

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