Offset locks to replace exhaust rotator retainers

Discussion in 'Small Block Mopar Engine' started by moparmandan, Sep 12, 2018.

  1. moparmandan

    moparmandan FABO Gold Member FABO Gold Member

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    Replacing exhaust rotators with intake non-rotator retainers. 360 smogger heads. What brand and part number lock do I need, please. Thanks for the help!
     
  2. Max1196

    Max1196 Well-Known Member

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    Were you planning on replacing the exhaust valve spring with something else?
     
  3. moparmandan

    moparmandan FABO Gold Member FABO Gold Member

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    I wasn't. Was going to use the factory spring with a factory grind cam. Should I? I am open to suggestions, though. Up to and including just run 'em cause at less than .450 lift I'm good.

    This is a first for me. I hear people say to get rid of the rotators but then not say how, LOL. Easy and cheap preferably. I have plenty of retainers, thanks to 66fs on here.
     
    Last edited: Sep 12, 2018
  4. Max1196

    Max1196 Well-Known Member

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    Using the stock 2 groove keeper (As found with rotator set up) with an intake retainer, the installed spring height will change by 100 thou. looser, shims of the equivalent amount would have to be added under the stock short exhaust spring to make up the difference. No off set keepers are not available. Using an intake spring with this set up on the exhaust also has a installed height issue. It becomes 100 thou. too tight, spring pad surface of the head would have to be modified (not advisable). The correct math is only found with the use of the 4 groove valve and keeper to use with a stock length intake spring on the exhaust.
     
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    • brian6pac

      brian6pac Well-Known Member

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      You can get offset keepers + or - .050
       
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      • Max1196

        Max1196 Well-Known Member

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        Not in 2 or 4 groove format.
         
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        • brian6pac

          brian6pac Well-Known Member

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          Your right single groove only,
           
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          • moparmandan

            moparmandan FABO Gold Member FABO Gold Member

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            Thank-you sir! That's what I needed to hear. New valves it is!
             
          • nm9stheham

            nm9stheham Well-Known Member

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            With stock springs rates of around 225 lb/in, + or -, using intake springs on the exhaust would result in around 25 lbs + or - more spring pressure, seated and open. Not a big change and less than the spring pressures for a standard heavy duty spring, like a Hughes 1110. So if it is not Hi-po, I think I'd just run the stock intake spring. Edit to add: .... once I had checked for any coil bind.
             
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            • Max1196

              Max1196 Well-Known Member

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              Using a stock intake spring with an intake retainer on a 2 grove exhaust valve will actually change the seated pressure from 70 lbs to 120 lbs, allowing for a "used condition" seated height of 1.500 stock to a 1.600 installed height (the attempted combo from above) and the open pressure changes from 172 lbs to 212 lbs at a low lift of .400 inch . coil bind IS not much more of a pull on the spring tester.
               
              Last edited: Sep 12, 2018
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              • nm9stheham

                nm9stheham Well-Known Member

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                Mmmmm... doesn't your closed pressure change vs installed height say a spring rate of 500 lbs/in? 50 lbs difference divided by 0.1" = 500 lb/in. Not a stock spring rate.....

                Or are you saying the installed intake spring height changes from 1.6 to 1.4" with those parts on the exhaust side?
                 
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                • moparmandan

                  moparmandan FABO Gold Member FABO Gold Member

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                  So coil bind is an issue? In rookie terms what is recommended? I don't mind buying aftermarket springs if that's a better option. I guess "getting rid of the rotators" is not as easy as some make it sound?
                   
                • moparmandan

                  moparmandan FABO Gold Member FABO Gold Member

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                  Over my head, but I'm listening and learning.
                   
                • mopowers

                  mopowers Well-Known Member

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                  I would just buy some cheap new valves and springs.
                   
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                  • Max1196

                    Max1196 Well-Known Member

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                    Valve keeper location with a 2 groove exhaust valve and using a rotator nets about a 1.500 spring installed height in used condition. This is using the non dampened spring for the comparison, seated pressure is 70 lbs. Then take the rotator off and install the intake retainer, still using the 2 (edited) groove keeper set up, you now have an installed height available at 1.600. But the original short stock exhaust spring now needs to be shimmed to rectify the loss of seated spring pressure OR select a spring that would net a sensible seated pressure, (not use the non dampened stock intake spring with the intake retainer and 2 groove valve/keeper combo that nets 120 lbs on the seat).
                    He can use stock intake springs and retainers with a new 4 groove exhaust valve to accomplish the correct math. Either way it's an 8 pack of springs or an 8 pack of valves.
                     
                    Last edited: Sep 12, 2018
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                    • moparmandan

                      moparmandan FABO Gold Member FABO Gold Member

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                      OR in reality since I looked and don't have enough of either, I get to buy new toys! Thanks so much for the education!
                       
                    • nm9stheham

                      nm9stheham Well-Known Member

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                      Roger...makes sense on the height now. But I believe the 120 lbs on the seat is in error for a 1.6-1.65" installed height for a stock 360 single spring of that vintage; should be in the 80-90 lb range ....????

                      120 lbs on the seat sounds more like a 340 spring.
                       
                    • Max1196

                      Max1196 Well-Known Member

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                      Yes, may seem so, but these are actual measured amounts as of yesterday. Not 340 stuff or not even stock stuff with a damper.
                       
                    • nm9stheham

                      nm9stheham Well-Known Member

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                      Thanks. Wouldn't have expected that based on the FSM data I have.

                      The OP can look at Melling VS-150 or Sealed Power VS-510 for a stock replacement spring. 80-90 lbs seat pressure at 1.650" installed height. Coil bind at around .450" lift if installed height is 1.65".

                      That is the problem with a stockish SBM springs... coil bind comes pretty easily, too easily for any cam of consequence. So a stiffer spring is needed with fewer coils or thiner wire to get a higher lift w/o getting too close to binding. And that leads back to higher seat pressures. I personally would not worry over 120 lbs seat pressure if the spring rate is not too high.

                      Melling VS1011 is a $2 spring for which coil bind occurs at about .485 lift with a 105-120 seat pressure and a 232 lb/in spring rate. That might work for the OP if the stock springs do not.

                      https://www.melling.com/wp-content/uploads/2017/03/valve-springs-identification-chart.pdf
                       
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                      • moparmandan

                        moparmandan FABO Gold Member FABO Gold Member

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                        Yes I bought the SP VS510 springs. Had 12 stock, so for the budget build my son and I are doing they'll be fine. Just a factory 340 grind for cam in a cruiser car. $1.99 @ Summit. For that matter the rotators probably would have lived, lol. Mostly doing this for his edumacation. Just something to run around while I plan a 408. Thanks for the help! That chart is awesome!
                         
                      • nm9stheham

                        nm9stheham Well-Known Member

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                        Good for you and working with your son! That is great!

                        OK, just look at coil spacing on a couple springs, (intake and exhaust) when you get the cam in. You won't see the problem when you put on the rockers and clamp them down; the lifters will likely be collapsed and not show this issue.

                        So you'll have to figure out a way to compress the valve and spring on the head by the amount of the valve lift for your cam; then check the coil spacing with a feeler gauge; you ought to be able to slip a .008"-.010" minimum feeler between the coils.

                        A SP VS510 is about the same as a Melling VS150 and those can be right at coil bind for .450" lift so you need to check for sure, because that is not adequate margin. .060" is the conventional wisdom for margin to coil bind, and you can often 'get away with 'a bit less until it gets over-revved. I.e., for a .450" lift, the valve should be able to move about .510" to coil bind. If the valve spring binds, then the likely results will be bent pushrods, with possible broken rockers.

                        Also, keep an eye on the retainer clearance to the valve stem seal and the the valve guide boss. This is easiest to check by assembling a valve, retainer and locks but no spring.
                         
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                        • moper

                          moper FABO Gold Member FABO Gold Member

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                          Stock cam - just leave them in place. If the cam is being upgraded to something mild, you can just replace the springs with Comp 901-16s and run the exhaust springs at the lower height. If it's getting a better camshaft beyond "mild" then replace the valves and all the retainers and locks.
                           
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                          • moparmandan

                            moparmandan FABO Gold Member FABO Gold Member

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                            Good info. I'll check when it's back together!
                             
                          • moparmandan

                            moparmandan FABO Gold Member FABO Gold Member

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                            Noticed Edelbrock makes a rotator valve spring while I've been searching this out. P/N 5977. Figures.............
                             
                          • Wyrmrider

                            Wyrmrider Well-Known Member

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                            not suggesting to run a .444 ex lift 340 cam with a .450 rated coil bind are we?
                            I would not run rotators with a high rate cam- the 340 is NOT a high rate cam but the weight might limit your rpm- rotator float and all that