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  1. #1
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    Default Valve spring dilemma SBC

    Hey guys,

    Need a little help advice here... bought a cam and matching valve springs from Crow Cams to go in my SBC build. Springs have a 1.700 install height. Problem is my new Edelbrock e-street heads come with valves at 1.750 install height.

    Im thinking of not changing the springs and leaving the Edelbrock springs in there. As the seat pressure @ .500 is identical (320) and the seat pressure is only 5 pounds more than the springs that came with the cam. Will need pushrods to suit new height but would work out lengths when I do my geometry.

    Will this be ok? Or do I need valve locks that bring the springs down another 0.050 if so any idea what angle / naming convention I look for when ordering?

    Thanks in advance.

  2. #2
    Sure why not? 76lxhatch's Avatar
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    If the heads already have springs that are suitable for the cam, the easiest solution is to use them. Make sure you check the max lift as well as seat and open pressures/rates, but chances are with a taller installed height this is fine.

    -0.050 valve locks (7 degree for standard style retainers) would allow you to install the other springs at 1.700 (1.750 - 0.050), or a set of 0.050" thick shims under the springs would do the same trick.

    Either way the valve doesn't move so the pushrod and rocker requirements don't change no matter which springs you use.

  3. #3
    Part of the furniture
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    HI
    U can buy shims to go under springs in different diameters . Check with various valvetrain suppliers . I do no that AFR making /sell/ reselling spring shims .
    Normal rules apply check all clearances piston/valve , coil bind , valve stem seal to retainer etc

  4. #4
    Do you ever leave? paulzig's Avatar
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    Do crow give you specs of the springs with coil bing distance and spring rate etc?

    The easiset way is shims, take the springs to someone with a spring tester check actual coil bind distance and pressures with the lift of your cam. The rocker ratio needs to be checked for accuracy if you want to push the coil bind distance closer

  5. #5
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    Hey guys, thanks for the replys! Called my machinist this morning and hes hooked me up with some shims.

    The cams lift is .448 and both springs have a max lift over 500 so Im not too worried about bind but will obviously check when setting up geometry.

    As for for spring rates, neither product sheet provided the data but I think my preference is to use the crow springs because they are matched directly to that cam.

  6. #6
    Do you ever leave? paulzig's Avatar
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    No spring specs? I know where I wont go for springs then lol....

  7. #7
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    Just be careful with 050 locks. Yet to use a set that goes the full 050, usually only 025-030.

  8. #8
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    Quote Originally Posted by Kingswood76 View Post
    Hey guys, thanks for the replys! Called my machinist this morning and hes hooked me up with some shims.

    The cams lift is .448 and both springs have a max lift over 500 so Im not too worried about bind but will obviously check when setting up geometry.

    As for for spring rates, neither product sheet provided the data but I think my preference is to use the crow springs because they are matched directly to that cam.
    Get on the Crow website and use the spring part number to check out spring rates, installed height etc.

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