valve spring seat pressures,ect.
+ Reply to Thread
Page 1 of 4 1 2 3 4 LastLast
Results 1 to 14 of 55

Thread:
valve spring seat pressures,ect.

  1. #1
    Senior Member hotbo's Avatar
    Join Date
    Feb 2008
    Location
    lake Ouachita AR
    Posts
    4,677

    Default valve spring seat pressures,ect.

    okay ive got a set of heads on a mill already built.they are performer rpm aluminum heads.


    heres my questions.they have 125lbs seat pressure,installed height is 1.975.open is around 310 suppose to be. coil bind around 1.160.

    spring diameter is 1.55.

    okay i need around 140-145 for my solid lifter flat tappet cam.can i shim the springs that are already on there to gain the 140 -145lbs seat pressures i need or do i need to buy other springs.if i shim does this change open pressures alsomaybe dumb questions but i want to learn.they say they are good for .700 lift but my profile will not be this big.thanks as always for any help,travis

  2. Remove Advertisements
    PerformanceBoats.com
    Advertisements
     

  3. #2
    Senior Member Hass828's Avatar
    Join Date
    Dec 2007
    Location
    okie, lake Texoma
    Posts
    6,278

    Default

    Quote Originally Posted by hotbo View Post
    okay ive got a set of heads on a mill already built.they are performer rpm aluminum heads.


    heres my questions.they have 125lbs seat pressure,installed height is 1.975.open is around 310 suppose to be. coil bind around 1.160.

    spring diameter is 1.55.

    okay i need around 140-145 for my solid lifter flat tappet cam.can i shim the springs that are already on there to gain the 140 -145lbs seat pressures i need or do i need to buy other springs.if i shim does this change open pressures alsomaybe dumb questions but i want to learn.they say they are good for .700 lift but my profile will not be this big.thanks as always for any help,travis
    Yes , shims will also change the open press.
    It depends on what open press. your looking for with the new cam and if you have room to shim them without coil bind problems.
    If you dont have the tools, just take them to a machine shop and have them checked, find out what installed hieght they would have to be shimmed to to achieve the 140-145lb seat press then see what the open press would be with the lift that your cam card shows. Dont forget to acount for lash as most cam cards show gross lift and dont subtract for lash.
    I'm usually not lucky when it comes to this and wind up buying new springs, kind of anal about having the exact pressures that the cam card asks for.
    On a roller I dont mind having 20lbs more open than the card says but with the luck that everyone has been having with the flat tappets loosing lobs, I would go strictly by the card. Good luck

  4. #3
    LP-25.com Infomaniac's Avatar
    Join Date
    Dec 2007
    Location
    New Port Richey, FL
    Posts
    16,872

    Default

    Compress the spring to the required seat pressure. Use this dimension as the installed height. Subtract valve lift and leave yourself .080 - .100 for a margin. Compare this to coil bind. If the installed height - lift - margin is more than coil bind you are good to go.

    But you don't want to stack up a ton of shims to get it there. Start at the installed height and compress it the dimension of valve lift. look at the open pressure and compare to what is required also.

    Bring them to the shop and we will look at it for you.

  5. Remove Advertisements
    PerformanceBoats.com
    Advertisements
     

  6. #4
    Sit N' Spin Jetaholic's Avatar
    Join Date
    Dec 2007
    Location
    Droppin' the kids off at the pool
    Posts
    1,423

    Default

    Installed height will determine what your seat pressure will be.

    Spring rate and lift will determine the difference between your seat and open pressures. THEORETICALLY, this difference should stay the same no matter what your seat pressure happens to be. In other words, with a spring rate of 350lbs per inch of spring travel and say for example sake, .565 of lift, you SHOULD have a difference of 197.75lbs between your seat and open pressure no matter what your seat pressure happens to be. With a seat pressure of 125lbs, this will give you an open pressure of 322.75lbs. If you shimmed the springs to give, say, 135lbs on the seat, this would change your open pressure to 332.75lbs.

    Of course, the above example is assuming the above mentioned spring measures out to exactly what it says it's supposed to measure out to and that the spring rate stays linear throughout the entire spring travel, but you get the idea.



    Quote Originally Posted by HammerDown
    Kendall L-427 Super Blu...extreme-pressure (ep) lithium complex keeps my thrusting balls happy
    Quote Originally Posted by back2k5 View Post
    Well I am putting in a nice stereo system in the Carrera...maybe Ill put on some rap and turn the scoop sideways

  7. #5
    Senior Member hotbo's Avatar
    Join Date
    Feb 2008
    Location
    lake Ouachita AR
    Posts
    4,677

    Default

    okay i guess i left out the part about the motor is together running good and im not going to buy 100 plus dollar head gaskets just to take them to have them set-up at a shop

    i wouldnt think you would need a ton of shims to add say 15lbs seat pressure?the cam has .612 gross lift.that outta be plenty of clearance if edelbrock says they are good to .700 lift

    just trying to figure a way to run my flat tappet and get away from hyd.i hate them with a passionand do it without tearing a mill apart.im sure there is a way i can do thisi have a tool to measure seat pressure with the heads on the mill.i can get a height checker ive never used one but there is a first time for everything.

    so what is best without tearing the sob apart trying to shim or buy the correct springs and setting them up on the heads with them still on the motor

  8. #6
    mo balls than $cents$ IMPATIENT 1's Avatar
    Join Date
    Dec 2007
    Location
    hugo,okla
    Posts
    11,733

    Default

    you're gonna run a solid flat in the tunnel?

  9. #7
    [email protected]
    Join Date
    Feb 2008
    Location
    Ohio
    Posts
    1,011

    Default

    Guys change springs at the track all the time. Don't see why you can't do it in the shop. Air compressor and a stud mount spring compressor should do it.

    Tim

  10. #8
    LP-25.com Infomaniac's Avatar
    Join Date
    Dec 2007
    Location
    New Port Richey, FL
    Posts
    16,872

    Default

    You can do it on the engine. Measure heights on the engine. Spring pressures are measured off the head anyway.

    When I was doing them at home, I used the valve height mic and a spring pressure tester that was hydraulic and used in a drill press or arbor press etc.

  11. #9
    Senior Member hotbo's Avatar
    Join Date
    Feb 2008
    Location
    lake Ouachita AR
    Posts
    4,677

    Default

    Quote Originally Posted by IMPATIENT 1 View Post
    you're gonna run a solid flat in the tunnel?
    yeah for this season anywayi already have the cam.cant afford what i want to do since i had to finace the boat .the mill is mild anyway the best part is the heads.crane gold rollers and comp stud girdles

  12. #10
    mo balls than $cents$ IMPATIENT 1's Avatar
    Join Date
    Dec 2007
    Location
    hugo,okla
    Posts
    11,733

    Default

    Quote Originally Posted by hotbo View Post
    yeah for this season anywayi already have the cam.cant afford what i want to do since i had to finace the boat .the mill is mild anyway the best part is the heads.crane gold rollers and comp stud girdles
    gotcha, leave it for next winter upgrade are you gonna sell the sj?

  13. #11
    Senior Member hotbo's Avatar
    Join Date
    Feb 2008
    Location
    lake Ouachita AR
    Posts
    4,677

    Default

    Quote Originally Posted by Infomaniac View Post
    You can do it on the engine. Measure heights on the engine. Spring pressures are measured off the head anyway.

    When I was doing them at home, I used the valve height mic and a spring pressure tester that was hydraulic and used in a drill press or arbor press etc.
    i have compressor,spring changer ect for changing them on the mill,not a problem,just dont know how to check all the shit that apparently is important,lol!!!im willing to learn as i dont trust most places to set them up anyway

    i have a set of 930-16 comp springs,close to new.they will fit but the installed height is different on the srping,the springs are rated at 142lbs seat at 1.95 i thinkso what would i have to do to run them?

  14. #12
    mo balls than $cents$ IMPATIENT 1's Avatar
    Join Date
    Dec 2007
    Location
    hugo,okla
    Posts
    11,733

    Default

    buy this:

    http://store.summitracing.com/partde...5&autoview=sku

    if the springs are new, they should be a certain seat pressure at a certain installed height, just get the seat pressure right, then turn the motor over and see what kinda clearence the springs have. every time i had my covers off to check lash, i'd check my springs as well. i went thru 2 sets of springs this past summer.

  15. #13
    Senior Member hotbo's Avatar
    Join Date
    Feb 2008
    Location
    lake Ouachita AR
    Posts
    4,677

    Default

    Quote Originally Posted by IMPATIENT 1 View Post
    buy this:

    http://store.summitracing.com/partde...5&autoview=sku

    if the springs are new, they should be a certain seat pressure at a certain installed height, just get the seat pressure right, then turn the motor over and see what kinda clearence the springs have. every time i had my covers off to check lash, i'd check my springs as well. i went thru 2 sets of springs this past summer.
    ive got that already loserthats excatly what i have

  16. #14
    mo balls than $cents$ IMPATIENT 1's Avatar
    Join Date
    Dec 2007
    Location
    hugo,okla
    Posts
    11,733

    Default

    Quote Originally Posted by hotbo View Post
    ive got that already loserthats excatly what i have
    then learn to use it

+ Reply to Thread
Page 1 of 4 1 2 3 4 LastLast

Quick Reply Quick Reply

Register Now

Please enter the name by which you would like to log-in and be known on this site.

Please enter a password for your user account. Note that passwords are case-sensitive.

Please enter a valid email address for yourself.

Please select your insurance company (Optional)

Log-in

Tags for this Thread

Digg This Thread

Posting Permissions

  • You may post new threads
  • You may post replies
  • You may not post attachments
  • You may not edit your posts
  •  
 

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95