Register now to get rid of these ads!

sbc blow by question

Discussion in 'The Hokey Ass Message Board' started by guido`s 40, Jan 22, 2013.

  1. toxic waste
    Joined: Dec 18, 2011
    Posts: 383

    toxic waste
    from Iowa

    Hook up the starter and do a compretion test to see what presseure you have.
    Joined: Jun 6, 2005
    Posts: 1,887

    Member Emeritus

    Did the engine exhaust smoke severely after it was running? or only leak oil out the seals?
  3. isky1843
    Joined: Feb 3, 2011
    Posts: 157


    Don't add oil to the cylinders. You will just be hindering your progress. Do another leak down test at 100psi and report back with results. While doing the test, check for leakage from the crankcase and also around the valves and in the water jacket. You can use a lit cigarette around the valve springs to find air escaping. Determine where the source of the leakage is. That will narrow it down. If it won't register on the second gauge when you put air to it, someone forgot to put the pistons in so you should go ahead and pull the heads.
  4. 64falconsix
    Joined: Jan 3, 2013
    Posts: 129

    from Daphne Al.

    Wrong rings, broken rings or incorrect gap ,
    Last edited: Jan 22, 2013
  5. cartoon14
    Joined: Jan 21, 2013
    Posts: 46


    cast or molly? did you install top ring and second ring dot up or down? if the bevel is is up compression will push past compression rings...just say'n molly rings are harder and take forever to seat don't like them myself but just my opinion
    Joined: Mar 22, 2006
    Posts: 2,059

    from OHIO

    Totally untrue when the cylinders are honed properly and engine is assembled with proper lubes. (not atf,gear lube,50w,synthetics)

  7. Mr48chev
    Joined: Dec 28, 2007
    Posts: 26,914


    I have to agee with Goagroper02 on the moly rings. They seat and work great in a fresh bore. It's on older engines that you just do a rering job on that moly rings sometimes give trouble.

    I'm thinking wrong rings, wrong size rings or improperly installed rings. The amount of blow by you are getting is more like an engine that is due for a rebuild than one that has just been rebuilt.
  8. Thunderroad312
    Joined: Nov 18, 2012
    Posts: 159


    If it is leaking that bad, you don't need guages to tell it needs to come apart. While I agree that improper crankcase venting will cause oil to blow out, the fact that it is leaking past the rings that badly indicates you need to pull it down and figure out WTF happened. My bet is either upside down or broken rings. Sorry JMO.
  9. toxic waste
    Joined: Dec 18, 2011
    Posts: 383

    toxic waste
    from Iowa

    What did you find was wrong ?

  10. Johnny Wishbone
    Joined: Aug 10, 2009
    Posts: 314

    Johnny Wishbone

    What kind of rings? Conventional, gapless? Just curious.
  11. guido`s 40
    Joined: Jan 23, 2011
    Posts: 150

    guido`s 40
    from nebraska

    I am just putting the motor back together had it honed and put new rings in everything else looked pretty good. Just figured the rings never had a chance to seat running the synthetic oil
  12. Window Licker
    Joined: Apr 18, 2009
    Posts: 285

    Window Licker

    if it was me, id get ahold of the machine shop that built the motor. a lot of shops i know hate when people bring back motors they've pulled apart or messed with.
  13. Jack E/NJ
    Joined: Mar 5, 2011
    Posts: 585

    Jack E/NJ
    from NJ

    And the result of the simple compression test is....????

    Jack E/N

Share This Page

Register now to get rid of these ads!


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.