Register now to get rid of these ads!

Technical Dual valve springs on a mild 327- thoughts on break in, replacement

Discussion in 'The Hokey Ass Message Board' started by 327Eric, Nov 23, 2014.

  1. 327Eric
    Joined: May 9, 2008
    Posts: 2,116

    327Eric
    Member

    I am building a mild 327 for my ElCamino. Got a set of 461 heads in a trade, with 2.02/1.60 valves, and dual valve springs. My cam is an old SSI cam from PAW, identical to the 350 horse 327, but with slightly less(.436 )lift
    I have seen plenty of stories about removing the inner springs for break in, but always on the larger cams, and a few guys saying the older style cams would be ok. The other question is, can i remove the inner springs and run the outer only(for the life of the engine, not just break in) or replace with a stock diameter , appropriate spring? (the seat has been cut)my ultimate goal will be to add 1.6 rockers to bring the lift to .466. Thoughts? I've researched this somewhat already, but all old info.
     
  2. gimpyshotrods
    Joined: May 20, 2009
    Posts: 23,263

    gimpyshotrods
    ALLIANCE MEMBER

    Is the cam coated with break-in lube?

    0.436" is not a ton of lift, neither is 0.466".

    I would put/leave the dual springs in, lube up the cam and lifters, run a Zinc-rich oil, do a proper break in, and not worry.

    Old info is still good info. The metal does not know how old it is.
     
  3. Always run the double springs,this would have been catastrophic with my 327 had I done what you propose.

    After this happened I replaced them all just to be safe. HRP

    [​IMG]
     
  4. JOECOOL
    Joined: Jan 13, 2004
    Posts: 2,771

    JOECOOL
    Member

    Find out what he springs actually have for lbs. and then talk to the cam grinder. Nothing wrong with break in with one spring but you need to know the cam and springs are matched.
     

  5. George
    Joined: Jan 1, 2005
    Posts: 7,723

    George
    Member

    Not a matter of dual or single but the spring pressure. If high on dual some are removing inner springs until break in is done. As Joe said, you need springs that match your cam.
     
  6. 61falcon
    Joined: Jan 1, 2009
    Posts: 772

    61falcon
    Member

    as others have said, knowing your spring pressure is important otherwise your jut guessing and taking a risk of cam damage and valve train problems.
     
  7. My opinion,,,,,Those are NOT dual springs..just springs with a damper in them,,,,,
     
  8. aaggie
    Joined: Nov 21, 2009
    Posts: 2,530

    aaggie
    Member

    327s like to rev so a stable valve train is important. Know what your installed height is and check the spring pressure at the installed height. The flat damper is to keep the harmonics under control. Modern cams have much better springs and seldom require double springs for street use.
     
  9. The message here is to make sure "Installed Height" is all the same..you will need various thickness spring shims to correct this..as all valves may not be sunk in the head the same from seat grinding operation..Therefore there will be different amount of shims on each spring seat.
     
  10. With that cam you don't need dual springs, I would run stock-ish springs with dampers. You know like the old power pack heads. If you run too stiff a spring on that cam you'll flatten it.
     
  11. sdluck
    Joined: Sep 19, 2006
    Posts: 3,185

    sdluck
    Member

    Make sure the pushrod holes are slotted ,1.6 rockers move the pushrods to a different position.
     
  12. 327Eric
    Joined: May 9, 2008
    Posts: 2,116

    327Eric
    Member

    The heads were a trade, so the specs are unknown. I talked to my machinist, and am just going to take the heads in and have him look at them and make his recommendations. Sucks because its all together, but I should have thought of this first. Been about 10 years since I've built a small block. Thanks for the advice guys.
     

Share This Page

Register now to get rid of these ads!

Archive

Copyright © 1995-2021 The Jalopy Journal: Steal our stuff, we'll kick your teeth in. Terms of Service. Privacy Policy.

Atomic Industry
Forum software by XenForo™ ©2010-2014 XenForo Ltd.