Register now to get rid of these ads!

Technical VALVE SPRING QUESTION

Discussion in 'The Hokey Ass Message Board' started by wingspread7, May 21, 2019.

  1. wingspread7
    Joined: Mar 29, 2009
    Posts: 737

    wingspread7
    ALLIANCE MEMBER

    I have a 390 Caddy engine rebuilt about 25 years ago. Not having been turned over yet the valve springs have been in various compressed stages. Should I just replace them all or am I being anal?
     
  2. squirrel
    Joined: Sep 23, 2004
    Posts: 42,728

    squirrel
    Member

    I've never had problems because of that.. If you want to just have fun, drive the car around for awhile and see how it does. Then fix what actually needs fixing.
     
    RDR, 47ragtop and olscrounger like this.
  3. wingspread7
    Joined: Mar 29, 2009
    Posts: 737

    wingspread7
    ALLIANCE MEMBER

  4. If the valve springs have taken a set, they weren't good valve springs in the first place.
     
    Truck64 likes this.
    Register now to get rid of these ads!

  5. Truck64
    Joined: Oct 18, 2015
    Posts: 3,178

    Truck64
    Member
    from Ioway

    If engine hasn't been run in yet, they are supposed to be heat cycled before hard use. At least, that's what the valve spring makers claim.

    "It is important for new valve springs to take a heat-set. Never abuse or run the engine at high rpm when the valve springs are cold. Upon initial start-up, limit rpm to 1500-2000 until the temperature has reached operating levels. Shut off the engine and allow the springs to cool to room temperature. This process will help eliminate premature failure and prolong valve spring life."
     
  6. Blues4U
    Joined: Oct 1, 2015
    Posts: 3,540

    Blues4U
    Member
    from So Cal

    It's fine for springs to remain compressed for extended periods of time. They do not lose tension from just remaining compressed, they lose tension from cycles. A spring that remains in a compressed condition will retain its strength.
     
    metlmunchr and Truckdoctor Andy like this.
  7. Mike VV
    Joined: Sep 28, 2010
    Posts: 1,477

    Mike VV
    Member
    from SoCal

    Two things hurt springs (of ANY kind), hard use (fast cycling), and heat, both internal (molecule friction) heat and external (hot engine) heat. I say "two" because with one type of heat, comes the second type of heat. And usually the fast cycling..!
    They can stay dormant in various stages of compression for many years without loosing more than a pound or two of force.

    Mike
     
    metlmunchr and Blues4U like this.
  8. wingspread7
    Joined: Mar 29, 2009
    Posts: 737

    wingspread7
    ALLIANCE MEMBER

    Thanks to all. Very good info. especially because I also have other rebuilt engines on stands.
     

Share This Page

Register now to get rid of these ads!

Archive

Copyright © 1995-2020 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.