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  • New cam = new lifters?

    As I'm planning my spring engine rebuild, I'm mulling cams and wanted to clarify a point on reusing parts:
    If I'm replacing the cam, should that always include getting new lifters too?
    And new pushrods, or not necessarily?

    The head is off of my engine block, so I pulled the lifters out with a magnet to inspect, they all look great - no pits, mirror finish, and 2 of them stuck together, so they're pretty flat. I don't know if that means the cam is in good shape, but it seems like a good sign. Pushrods likewise look good.

    As some background, the engine is a '69, and I don't think it's ever been rebuilt. I'm doing it primarily because it dropped the thrust washer with a previous owner, and there's crank damage that I've been putting off fixing. It's also using a fair bit of oil. The head was pretty crusty with carbon but looks in good shape after cleanup. I'm planning to bring it to the machine shop this week.

    So now I'm thinking through whether I should just reuse the existing cam (assuming it's good) or replace with the 311-399 or preferably the GP2 or BP270. I'll have the head shaved slightly for 9.5:1, so a little warmer cam seems worth it. No other major work planned, I'm just aiming for a solid engine and some pep.
    Bill Connell
    1969 TR6 CC28790
    TR6 project log
    St. Paul MN

  • #2
    Hi Bill, I’m no expert but here’s what I did on my TR250. New 150HP PI Cam, New HD lifters, Old shortened pushrods.

    Cheers,
    Tush
    81 Alfa Romeo Spider Veloce, 81 Triumph TR8
    73 Triumph TR6 CF4874UO, 68 Triumph TR250 CD5228LO
    62 Triumph TR4 CT6716LO, 60 Triumph TR3A TS69891LO
    60 Triumph TR3A TS64870LO, 59 Triumph TR3A TS44836LO
    https://www.youtube.com/user/cheftush

    Comment


    • #3
      FWIW, Richard Good suggested when doing the GP2 Cam to do double valve springs. I went with new lifters that he sells as well. Since you're headed down the slope, think about porting a bit and a header. It's only money
      So much rust, so little time

      64 TR4 Overdrive Surrey
      67 GT6 Mk1
      68 TR250 Soon to have Overdrive & Surrey
      71 TR6 Hardtop Soon to have OD
      81 TR8 Injected Automatic...the LAST Automatic

      Comment


      • #4
        Thanks for the note. My original single springs are out of spec, so new spring choice will definitely be a question to whoever I get the cam from.
        Bill Connell
        1969 TR6 CC28790
        TR6 project log
        St. Paul MN

        Comment


        • #5
          TL;DR If you’re going to replace the cam I would also replace the lifters.

          The typical failure mode for lifters, spalling, is a fatigue failure. Fatigue is a result of repeated stress cycles, the more cycles, the more likely you are to see a fatigue failure. If as you say the lifters are as old as the cam then they won’t have as much life left in them as your new cam will have. Then there’s the issue of break in, the old lifters are honed to the shape of the old cam and will see additional stress as they wear in to the new cam. Your “stick together” test is a fair indication of flatness, but not a perfect one, you won’t be able to measure the tiny amount of not flat without very precise instruments. Whatever out of flat there is won’t match the out of flat of the cams and so additional wear will be happening. If you’re going to spend on a new cam I’d say it’s cheap insurance to spend a little more on new lifters. On the other hand, the old lifters will certainly work they just may not last as long as the cam and boy, it sure is fun to spend other people’s money!
          ‘70 TR-6

          Comment


          • #6
            Hi Bill
            I have an early TR6 motor and retained the early head when it was rebuilt. Wishbone Classics did the work and managed 142 HP at 5500 and 155 lb/ft torque at 3500 with all stock externals. (Torque is 150 at 2600 and above 150 from 3000 to 4600, its a great street build). The head was shaved to 9.6, a good cam like you are looking at, ported intake (there is a big gain there) and fan eliminator. Oh and a lightened flywheel to help it rev. The later head and intake are worth 10-20 HP on the same build. At the same time Wishbone built a later engine with the same cam, a header and twin Mikuni bike carbs and that was worth 170 or 175 HP if memory serves.
            Always new lifters on a new cam, always! And you do need the right springs to get the most out of the cam from a performance POV and the most out of the lifters from a life POV.
            Keep us posted please!

            Comment


            • #7
              Thanks for the feedback, I'll definitely plan on new lifters. I talked briefly with Leighton at BPNW, and he said that he actually prefers the standard (not HD) lifters for all the but the race-oriented cams, so something else to think about (and maybe save a bit of money).

              Related question: is it reasonable to run the 311-399 cam and keep the single spring setup? Leighton said that it's possible to run the BP270 with single springs, but there's a risk of floating the valves above 5k rpms. I know Richard Good recommends his double springs for the GP2 cam, but his set is $85 and out of stock. If it change to double springs I'd also need new lower collars and I think new upper collars for the exhaust? Seems a lot simpler to just replace the current single springs with new ones (mine are a bit short).
              Bill Connell
              1969 TR6 CC28790
              TR6 project log
              St. Paul MN

              Comment


              • #8
                IMHO, RG designed, tested, built, raced and then sold the double springs with his GP2. If he says they need double springs, then get the double springs. That goes for any other cam too.

                My understanding is the BP270 is very similar to the GP2, so it would seem to me it needs double springs too. I don't know anything about the 311-399.

                Also, I don't like the idea of matching parts from different suppliers. That can lead to problems.

                All IMHO.
                1972 Sapphire TR6 #CC84,something

                1959 Red TR3 (Wife's)

                Comment


                • frostr6
                  frostr6 commented
                  Editing a comment
                  With RG's parts, I trust that everything he sells has been specifically engineered to work together, and it makes sense to get the whole package from him. I don't know if that's necessarily as true for other parts suppliers, though I'd trust their recommendations.

                  Part of what I'm getting hung up on is figuring out what I need to convert to double springs, the suppliers' diagrams online are not very helpful. Like, the lower collars pictured for double springs just look like spacers, and not seats that locate the springs like for the single setup. It's also not clear if I can reuse my 2-piece exhaust valve upper keepers or if I have to get new ones.
                  Last edited by frostr6; 11-20-2020, 10:50 AM.

              • #9
                The 311-399 is the stock TR6 cam for the 73 thru 76 cars and double springs were what was used with that cam. You probably won't be saying "It's got a cam" but it's a good cam suited for the TR6 engine's bore and stroke.
                I have it with the same double springs that were used when the engine had an S3 cam.
                They have been tested at least 3 times at the machine shops when the head was reworked..I don't know how they measured but apparently they are still good.
                I believe the springs along with that S3 cam originally came from Ted Schumacher's shop.
                And put me in the fresh tappets camp.
                I bought the 311399 cam and these tappets from BPNW
                https://www.bpnorthwest.com/triumph/...1500-1098.html



                Driving a 1973 TR6
                Doing ZS carb repairs
                email kencorsaw"at"aol.com

                Comment


                • frostr6
                  frostr6 commented
                  Editing a comment
                  The 399 would be a mild upgrade cam for my early engine, and matches pretty well what I want to do with the car (in-town driving, weekend trips). But then part of me says that if I have to switch a bunch of parts to a double spring setup no matter what, maybe it makes sense to go a bit further. On the third hand, I've also seen comments from you and others that the difference between the cams I'm considering isn't that great, so maybe the cheaper 399 is the better choice anyway.

              • #10
                If you've been mulling over cam choices, you probably have seen this comparison chart, but if not you may find it helpful...notice the RPM ranges, too.
                http://www.hottr6.com/triumph/tr6cams.html
                Driving a 1973 TR6
                Doing ZS carb repairs
                email kencorsaw"at"aol.com

                Comment


                • #11
                  Yes, that's a helpful page, though I wish it were a little more up to date. I've been doing a lot of reading in the archives here and at Triumphexp and other boards, and I'm trying not to start yet another "which cam" thread, because it seems like not much has really changed and the discussions mostly repeat.

                  I can't remember where I found the link, but this google doc spreadsheet has more of the currently available cams, though it doesn't calculate the lobe center angle, which is a useful data point:
                  https://drive.google.com/file/d/1mUj...wqw03aJ7p/view
                  Bill Connell
                  1969 TR6 CC28790
                  TR6 project log
                  St. Paul MN

                  Comment


                  • #12
                    Let us know what you decide...I don't think out of the 3 or 4 you're considering there's a bad choice.
                    Driving a 1973 TR6
                    Doing ZS carb repairs
                    email kencorsaw"at"aol.com

                    Comment

                    New cam = new lifters?

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