1. ir3333

    ir3333 Well-Known Member

    Messages:
    4,857
    Likes Received:
    1385
    Joined:
    Jun 1, 2008
    Location:
    ontario,canada
    Local Time:
    3:51 AM
    Are the any oiling mods necessary when using 273 adjustable rockers with hydraulic lifters?
    A friend suggested by pre-loading the lifters the oiling hole is compromised?
     
  2. yellow rose

    yellow rose Overnight Sensation FABO Gold Member

    Messages:
    28,537
    Likes Received:
    24967
    Joined:
    Jun 19, 2015
    Location:
    Central Washington
    Local Time:
    1:51 AM
    You must banana groove the shaft. Otherwise, especially at idle you won’t get any oil between the rocker and the shaft and the rocker will grab the shaft.
     
    • Like Like x 1
    • 383Scampman

      383Scampman Well-Known Member

      Messages:
      1,808
      Likes Received:
      1013
      Joined:
      Nov 24, 2013
      Location:
      New Hampshire
      Local Time:
      4:51 AM
      If you use solid lifter pushrods with hydraulic lifters the pushrods are too short and all kinds of negative stuff happens .
       
    • ir3333

      ir3333 Well-Known Member

      Messages:
      4,857
      Likes Received:
      1385
      Joined:
      Jun 1, 2008
      Location:
      ontario,canada
      Local Time:
      3:51 AM
      i think you have that backwards.Solid cam 273's had 7.5" pushrods and are too long for hydraulic lifters.
       
      • Agree Agree x 1
      • ir3333

        ir3333 Well-Known Member

        Messages:
        4,857
        Likes Received:
        1385
        Joined:
        Jun 1, 2008
        Location:
        ontario,canada
        Local Time:
        3:51 AM
        YR...the oil hole in the new shafts i have is quite large and located right on the bottom where the pressure would be...but i'm thinking those rockers will only move 3/16 - 1/4 inch and should see enough oil.
        Your thoughts?
         
      • 1966Post

        1966Post Well-Known Member

        Messages:
        211
        Likes Received:
        53
        Joined:
        Mar 8, 2015
        Location:
        Wisconsin
        Local Time:
        3:51 AM
        Pretty sure the factory banana grooved the adjustable rocker shafts for a reason
        I've used the whole assembly on multiple hydraulic camshafts and never had an issue. There are many articles on how much preload to set the adjustment to here or on the web.
         
      • perfacar

        perfacar Well-Known Member

        Messages:
        1,092
        Likes Received:
        285
        Joined:
        Mar 1, 2006
        Location:
        renton,wa
        Local Time:
        1:51 AM
        cut banana grooves . factory shafts had them for a reason!
         
        • Agree Agree x 1
        • ir3333

          ir3333 Well-Known Member

          Messages:
          4,857
          Likes Received:
          1385
          Joined:
          Jun 1, 2008
          Location:
          ontario,canada
          Local Time:
          3:51 AM
          no doubt the banana grooves will improve oiling, and additional holes in the rocker too.
          But not all 273's had banana grooved rocker shafts. Anybody know if slant six rocker shafts were grooved those things run forever?
           
          • Agree Agree x 2
          • 1966Post

            1966Post Well-Known Member

            Messages:
            211
            Likes Received:
            53
            Joined:
            Mar 8, 2015
            Location:
            Wisconsin
            Local Time:
            3:51 AM
            So no emotions involved here so please don't get butt hurt but...
            You started a post asking about this Then when people that know provide what your seeking you want to refute it That is your prerogative for sure free country and all that
            but I'm guessing you have a semi-performance build in mind given you wish to maximize your camshaft thru an adjustable rocker setup

            if you do actually have a six cylinder slug and it's a grocery gett'r then by all means use them as they are again your prerogative
            but when your rocker train goes squeak squeak and turns blue please just look in the mirror for the answer "why".....
             
            • Like Like x 1
            • pishta

              pishta I know I'm right....

              Messages:
              20,090
              Likes Received:
              9421
              Joined:
              Oct 13, 2004
              Location:
              Tustin, CA
              Local Time:
              1:51 AM
              Grooving the shaft is easy with a dremel and a cutting disk, just smooth out the corners.TA shafts had diagonal grooves, 273 had straight cuts iirc. Mech and hydro pushrods are too far off to interchange. Just get the correct ones. You can cut down slant pushrods to use on 273 rockers, just remove the hardened round tips, cut to size and press the tips back in. They are captive once they are installed so they dont need to be uber tight in there but will press in snugly.

              <<<PS I can't find an example of a straight cut now...>>>
               
              Last edited: Apr 26, 2020
              • Like Like x 1
              • Thanks! Thanks! x 1
              • Agree Agree x 1
              • Wyrmrider

                Wyrmrider Well-Known Member

                Messages:
                3,611
                Likes Received:
                1748
                Joined:
                Sep 5, 2016
                Location:
                los angeles
                Local Time:
                1:51 AM
                Yellow rose has posted on mods that need to be made to the rocker in addition to the ones on the shaft
                is there a stickie
                if not PM him
                if no response I'll try and make a pass at the problem and solutions
                I may have copied his comments in the 318 cam stickie (have fun)
                pss I likle to use oil through the pushrods to oil the cups and balls
                It looks like using cup adjusters and ball and ball end pushrods gives better geometry
                YR and I both suggest that you use the strongest pushrods you can fit no matter the cam
                 
                • Like Like x 1
                • Disagree Disagree x 1
                • ir3333

                  ir3333 Well-Known Member

                  Messages:
                  4,857
                  Likes Received:
                  1385
                  Joined:
                  Jun 1, 2008
                  Location:
                  ontario,canada
                  Local Time:
                  3:51 AM
                  All good info guys..tx.My engine is built and i made no modifications to the new stock shafts or rocker arms.A friend told me that i will be sorry and the modifications are necessary so thought i would ask on the forum.
                  As you know... i try to use logic and question most everything.
                  Now....who have used stock 273 adjustable rockers with standard shafts and how did they perform for you?
                   
                • Demonracer

                  Demonracer 71 Demon 00 Ram 16 Chrysler 300S 05 Caravan FABO Gold Member

                  Messages:
                  5,035
                  Likes Received:
                  3023
                  Joined:
                  Jan 31, 2010
                  Location:
                  Cleveland, Texas
                  Local Time:
                  3:51 AM
                  I've used after market ductile iron adjustable rockers on my bracket car motor with & without grooved shafts with no problems. A lot of it depends upon what you are going to use the motor for street, race, or combination. Mine is race only so I can't attest to street usage.
                   
                  • Like Like x 1
                  • Bodyperson

                    Bodyperson Pedal to the metal FABO Gold Member

                    Messages:
                    6,358
                    Likes Received:
                    8974
                    Joined:
                    Nov 26, 2015
                    Location:
                    NW MONTANA
                    Local Time:
                    2:51 AM
                    Cam a guy do that to the 273 pushrods? Pull them apart and shorten them.
                     
                  • ir3333

                    ir3333 Well-Known Member

                    Messages:
                    4,857
                    Likes Received:
                    1385
                    Joined:
                    Jun 1, 2008
                    Location:
                    ontario,canada
                    Local Time:
                    3:51 AM
                    Tx DR...we can all take a lesson from your response.
                    "This is what i used and this was the result"...Perfect!
                     
                  • Demonracer

                    Demonracer 71 Demon 00 Ram 16 Chrysler 300S 05 Caravan FABO Gold Member

                    Messages:
                    5,035
                    Likes Received:
                    3023
                    Joined:
                    Jan 31, 2010
                    Location:
                    Cleveland, Texas
                    Local Time:
                    3:51 AM
                    In order to get the correct push rods you will need to get a push rod length checker. Measure all of the push rods with whatever cam, lifters & rockers you plan to run, & some light weight springs. From there you can order the correct push rods for your application.
                     
                    • Agree Agree x 1
                    • Marcohotrod

                      Marcohotrod Well-Known Member

                      Messages:
                      2,424
                      Likes Received:
                      629
                      Joined:
                      Mar 21, 2015
                      Location:
                      Massachusetts
                      Local Time:
                      4:51 AM
                      I think solid lifters do not need grooves cuz of lash. hydraulic lifters constantly being loaded like the added grooves
                       
                    • ir3333

                      ir3333 Well-Known Member

                      Messages:
                      4,857
                      Likes Received:
                      1385
                      Joined:
                      Jun 1, 2008
                      Location:
                      ontario,canada
                      Local Time:
                      3:51 AM
                      That makes sense.
                       
                    • pt70

                      pt70 Well-Known Member

                      Messages:
                      403
                      Likes Received:
                      314
                      Joined:
                      Aug 23, 2019
                      Location:
                      CT
                      Local Time:
                      4:51 AM
                      The 273 I had lasted over 150,000 miles with little maintenance. Adjusted the valves when they got noisy. 2 bbl car with light springs? Decades ago.

                      273 adjustable rockers require a 273 rocker arm shaft. The holes in the shaft point to the carb base [on both sides]. I believe the banana groove only came from the factory on 340 six pack cars.
                       
                    • Rocket

                      Rocket FABO Gold Member FABO Gold Member

                      Messages:
                      2,159
                      Likes Received:
                      334
                      Joined:
                      Apr 22, 2005
                      Location:
                      Manchester, CT
                      Local Time:
                      9:51 AM
                      I would highly recommend using a banana grooved shaft with the factory iron rockers. Some reasons are mentioned above. Yellow Rose mentioned the rocker grabbing or sometimes called friction welding or galling. See last two pictures below of a damaged stock hydraulic rocker shaft without banana grooves from using the stock 273 rockers below. The higher the spring loads you have on your engine the more likely and quickly this will happen. As mentioned above a dedicated race car with high idle and limited run time at low RPM will extend the time this takes if at all.

                      I would suggest as the first choice in shafts for iron rocker arms is to use the factory 273 mechanical rocker arm shaft as there are other differences will point out. First the banana groove which was already discussed.

                      Second is a there is a second oil hole drilled for the push rod cup which provides pressurized oil directly to the cup to lubricate and cool another critical friction point.

                      Third the two oil holes in the mechanical rocker 273 shafts are smaller that the one larger hole in the stock hydraulic or aftermarket one hole shaft.

                      Fourth if I recall correctly is the mechanical 273 shafts have the bottom oil hole and the banana groove clocked slightly towards the valve springs rather than straight down to optimize the oiling where the load is when the rocker is in the lift cycle. Something like the minute hand on a clock when it is at 6:35.

                      Some aftermarket rockers have an internal groove around the inside to feed pressurized oil to the pushrod cup oiling hole in the rocker arm - Hughes for example and the Crane iron rocker arms. The stock 273 rockers do not have this groove. Chrysler added the additional hole is in the shaft instead.

                      Will the pushrod cups get oil without the groove in the rocker arm or added oiling hole in the shaft. Yes it will get some but it will not be as effective as a second hole in the shaft.

                      So for me my preference when I use mechanical rocker arms, regardless of application, street or race, is to always use banana grooves shafts and a shaft with an oiling hole for the pushrod. If the rocker has an internal oil groove in the rocker body to get oil to the pushrod cup then I may consider shafts that have a banana groove and no additional oil hole in the shaft for the pushrod but it will depend on the application. I tend to like the additional insurance of the additional pushrod oiling hole in the shaft.

                      I also added a couple shots some 273 mechanical rocker shaft to show the two oiling holes and the oiling hole sizes.

                      C04265B1-DBAB-4A98-B8E1-C4D4A500C453.jpeg 04F19537-A47F-4180-8AB1-047E9D55A434.jpeg E0E9350A-297E-4E5D-8289-0B52A768B19B.jpeg 1C56CA3A-151C-40B7-A5FF-592E63088988.jpeg 55294599-DCF5-4A4F-A7B8-D09D3ECCEFAB.jpeg C3EC76A3-DCE2-4AC2-854C-6363FF8486D9.jpeg 91030B9B-3AD7-4E22-81C0-203B5A5EAC48.jpeg
                       
                      Last edited: Apr 25, 2020
                      • Like Like x 2
                      • Agree Agree x 1
                      • Wyrmrider

                        Wyrmrider Well-Known Member

                        Messages:
                        3,611
                        Likes Received:
                        1748
                        Joined:
                        Sep 5, 2016
                        Location:
                        los angeles
                        Local Time:
                        1:51 AM
                      • perfacar

                        perfacar Well-Known Member

                        Messages:
                        1,092
                        Likes Received:
                        285
                        Joined:
                        Mar 1, 2006
                        Location:
                        renton,wa
                        Local Time:
                        1:51 AM
                        ok, the 273 came with angled grooves cut in the shafts from the factory. my original 273 dart came that way, it had 25,000 miles on it never been apart. they were never cut straight.
                         
                        • Agree Agree x 2
                        • nm9stheham

                          nm9stheham Well-Known Member

                          Messages:
                          12,090
                          Likes Received:
                          3959
                          Joined:
                          Dec 20, 2013
                          Location:
                          Waynesboro, VA
                          Local Time:
                          4:51 AM
                          /6's are not a comparable example: all solid lifters and adjustable rockers 'til the last few years. So no need for the groove in the shaft. But they had grooves in the rockers for oil distribution from the single oil hole in the shaft for many years for both types, and when they went to the hydraulics in the last few years, the rocker grooves changed a bit.
                          Hydraulic vs. Mechanical cam valve train differences - Slant Six Forum
                           
                        • ir3333

                          ir3333 Well-Known Member

                          Messages:
                          4,857
                          Likes Received:
                          1385
                          Joined:
                          Jun 1, 2008
                          Location:
                          ontario,canada
                          Local Time:
                          3:51 AM
                          I dug out an original 273 rocker shaft from my scrap pile and see the additional oiling holes as well as the grooves.Also talked to a few guys that have run them with standard shafts and had no problems, but you guys have convinced me to use the 273 style for the additional oiling benefits.
                          Thanks to all....now the search for good used or new shafts begins
                           
                          • Like Like x 2
                          • PRH

                            PRH Well-Known Member

                            Messages:
                            3,211
                            Likes Received:
                            4732
                            Joined:
                            Dec 14, 2018
                            Location:
                            So. Burlington, Vt
                            Local Time:
                            4:51 AM
                            Great post and pics from Rocket:thumbsup:
                             
                            • Agree Agree x 2
                            1. This site uses cookies to help personalize content, tailor your experience and to keep you logged in if you register.
                              By continuing to use this site, you are consenting to our use of cookies.