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Valve Spring Testing 101

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  • #61
    Originally posted by lun40119 View Post
    The lobes I have in my engine are similar acceleration rates as the older truck stuff. I guarantee you if you need 300lbs of seat pressure you aren't using the right parts bud...with 130 lbs of seat pressure and .866 lift mine shows no bounce at 9000 rpm...
    Dont ya think PAC might know just a little about springs

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    • #62
      There seems to be a bit of an evolution going on with valve train mass, spring rates and associated lobe design. I was really surprised when we put mine together with the A460 heads and their tall valves the first time back in early 2006 and the valve spring of choice was essentially the same as the ones I'm using now with just a bit over 215# on the seat and 650 over the nose. We we're at 230# on the seat this time, but only .830 net lift on a big block, not pushing an inch like the SBC guys are.

      I'm following the build philosphy of trophy truck engines as they have to deal with harsh conditions and extended time at WOT or near to it for a 1000 miles or sometimes multiple races covering several 1000's of miles before refresh. Not the sophistication of Cup motors, but a well understood combination of bore sizes, ring packages, assessory drives etc. Each time we up the ante a bit I learn something and we go ont to the next build. I still want to keep doing all the stuff I do with the car, drags, auto-x, open course and soon standing mile, never mind the drives and driving events, so it'll never be close to what a lot folks make in terms of power etc.

      Like Bob says, I'm still learning.
      Drag Week 2006 & 2012 - Winner Street Race Big Block Naturally Aspirated - R/U 2007 Broke DW '05 and Drag Weekend '15 Coincidence?

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      • #63
        Originally posted by MR P-BODY View Post
        Dont ya think PAC might know just a little about springs
        Yes they do.....I know Matt pretty well. Just ordered a set of springs from him the other day.

        That being said.....Ill stand by my comment.

        300lbs of seat pressure on a small stem Ti valve? Wow.....
        Last edited by lun40119; June 12, 2013, 04:23 AM.
        Team Clueless
        1st Place SB/NA DW12
        2nd Place SB/NA DW11
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        • #64
          Originally posted by lun40119 View Post
          Yes they do.....I know Matt pretty well. Just ordered a set of springs from him the other day.

          That being said.....Ill stand by my comment.

          300lbs of seat pressure on a small stem Ti valve? Wow.....
          I would assume PAC asked what the components were before they
          suggested what spring.... I dont run Ti valves and run 320# on seat
          and have been as high as 9600 rpm in my SB but I didnt make any
          power up that high ... and I run PAC also

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          • #65
            Cool.....I am telling you, with a Ti valve and a truck grind.......it won't have 300lbs seat.
            Last edited by lun40119; June 12, 2013, 05:32 AM.
            Team Clueless
            1st Place SB/NA DW12
            2nd Place SB/NA DW11
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            • #66
              Originally posted by lun40119 View Post
              Cool.....I am telling you, with a Ti valve and a truck grind.......it won't have 300lbs seat.
              I understand what your saying.. I have run Ti valves in the past...
              but I wont run them on a so called street engine.... to pay $1000 for
              the intakes and get a shorter life cycle doesnt work for my street stuff

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              • #67
                Originally posted by MR P-BODY View Post
                I would assume PAC asked what the components were before they
                suggested what spring.... I dont run Ti valves and run 320# on seat
                and have been as high as 9600 rpm in my SB but I didnt make any
                power up that high ... and I run PAC also
                I was thinking about this more and more, and I am going to comment one more time and then let it go...

                Too much spring pressure can be just as bad if not worse than not enough. Think of it like cause and effect....excessive spring pressure causes excessive deflection........deflection "HAS" to be released. No way around it....it is released as loft, you will not ever "stick" the lifter to the lobe. Now you have separation, with so much spring rate you force the system back into deflection....and the cycle starts over.

                I am telling you right now, because I have seen it with my own eyes.....rigid valvetrain, reduce valvetrain mass, come off spring pressure. You will find that now you have control of the valve. As you reduce deflection you increase duration at the valve, odds are, you have too much lobe for what you are trying to do.
                Team Clueless
                1st Place SB/NA DW12
                2nd Place SB/NA DW11
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                • #68
                  Originally posted by MR P-BODY View Post
                  I understand what your saying.. I have run Ti valves in the past...
                  but I wont run them on a so called street engine.... to pay $1000 for
                  the intakes and get a shorter life cycle doesnt work for my street stuff
                  Can't you coat them? I have 11,000 miles on mine and they are going back in. Isn't the vette using a Ti valve in it from the factory?
                  Team Clueless
                  1st Place SB/NA DW12
                  2nd Place SB/NA DW11
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                  • #69
                    Yes, and Yes. The short life tells you it was not happy.
                    2007 SBN/A Drag Week Winner & First only SBN/A Car in the 9's Till 2012
                    First to run in the .90s .80s and .70's in SBN/A
                    2012 SSBN/A Drag Week Winner First in the 9.60's/ 9.67 @ 139 1.42 60'
                    2013 SSBN/A Drag Week, Lets quit sand bagging, and let it rip!

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                    • #70
                      Originally posted by JeffMcKC View Post
                      Yes, and Yes. The short life tells you it was not happy.
                      I guess your right... it didnt like 10,000 rpm for 3 years of racing... that was years ago

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                      • #71
                        What type of racing were you doing where you were seeing 10,000rpm? What was the combo.....just curious.

                        PS......spoke to a buddy also that works at an engine shop that builds truck engines.......6mm intake, 7mm exhaust..130ish/650ish spring pressures in that 2006ish era....

                        Then I asked about 300lbs seat on a 5/16 Ti stem.....he responded....."better have your shit together, won't tolerate much bounce or separation at all!!!"
                        Last edited by lun40119; June 12, 2013, 06:51 AM.
                        Team Clueless
                        1st Place SB/NA DW12
                        2nd Place SB/NA DW11
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                        • #72
                          Originally posted by lun40119 View Post
                          What type of racing were you doing where you were seeing 10,000rpm? What was the combo.....just curious.

                          PS......spoke to a buddy also that works at an engine shop that builds truck engines.......6mm intake, 7mm exhaust..130ish/650ish spring pressures in that 2006ish era....

                          Then I asked about 300lbs seat on a 5/16 Ti stem.....he responded....."better have your shit together, won't tolerate much bounce or separation at all!!!"
                          I was drag racing a 383 mopar destroked with a 4 speed in a tube chassis Valiant .... this was back
                          in the mid 70s

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                          • #73
                            Ok......I also have this stuff to share.......this is an older DEI Busch engine.....SB2.......just more food for thought.


                            Team Clueless
                            1st Place SB/NA DW12
                            2nd Place SB/NA DW11
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                            • #74
                              Drag racing is my true love.......but I am telling you right now. Us Drag Week guys, and actually all Drag Racing guys could really learn a lot from the cup/busch stuff. ESPECIALLY in the valvetrain department!!!
                              Team Clueless
                              1st Place SB/NA DW12
                              2nd Place SB/NA DW11
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                              • #75
                                I am in Realville, Cup motor 8500/9300 for 500 miles

                                Drag Motor 10,000 RPM for 3 seconds of 100 passes a year for three years

                                That's not much cycle time at 10,000, but he Captain Cave Man cams back then and junk Valve springs where a issue. Our Cam Dynamics cam had .736 lift and broke 2 springs at least every pass.
                                Last edited by JeffMcKC; June 12, 2013, 07:11 AM.
                                2007 SBN/A Drag Week Winner & First only SBN/A Car in the 9's Till 2012
                                First to run in the .90s .80s and .70's in SBN/A
                                2012 SSBN/A Drag Week Winner First in the 9.60's/ 9.67 @ 139 1.42 60'
                                2013 SSBN/A Drag Week, Lets quit sand bagging, and let it rip!

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