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Technical Valve cover clearance

Discussion in 'The Hokey Ass Message Board' started by 63401nailhead, Sep 22, 2022.

  1. 63401nailhead
    Joined: Apr 4, 2008
    Posts: 162

    63401nailhead
    Member
    from DE

    My valve covers have been leaking forever. I’ve tried both cork and rubber gaskets with crappy chrome plated steel (edelbrock 4449) valve covers multiple times over the years. Last week I finally tossed those and ponied up some bucks on the fancy fel-pro 1628 (thick rubber with steel inside) and cast aluminum valve covers (edelbrock 4262). No more leaks!
    However, now I’m hearing a tapping noise that I’ve never heard before (under load, mostly in first gear).

    Could this be a clearance issue with the aluminum valve covers? They actually appear to be a tad taller than the old chrome covers and the gasket I’m using now is thicker. Is something else going on and this is just a coincidence? Or am I slapping the inside of the valve cover?
     
  2. Johnny Gee
    Joined: Dec 3, 2009
    Posts: 10,303

    Johnny Gee
    Member
    from Downey, Ca

    Only one way to see if there is internal interference. Then there’s acoustics being amplified now with these new covers?
     
    firstinsteele likes this.
  3. nunattax
    Joined: Jan 10, 2011
    Posts: 2,951

    nunattax
    Member
    from IRELAND

    take one off and have a look in.if there is interference you will see indents on the inside cover.what rockers are you using.sounds like you are using similar gaskets to me.i stuck my thick gaskets to the heads with permatite black and greased the top of the gasket.no leaks here with chevy cast finned covers.i cleaned the gasket surfaces in the cover with a cloth and white spirit left them to dry well before fitting
     
    bobss396 likes this.
  4. Jalopy Joker
    Joined: Sep 3, 2006
    Posts: 29,197

    Jalopy Joker
    Member

    use section of garden hose, or even long screw driver or stethoscope and take a listen - breathers use same vent style & same location?
     
    Bob Lowry likes this.

  5. Mr48chev
    Joined: Dec 28, 2007
    Posts: 31,577

    Mr48chev
    ALLIANCE MEMBER

    A Mechanics stethoscope is great for this but the heater hose or broom stick or long screw driver will get the job done if you don't have one.

    Some off those cast covers are tall enough but taper just enough that the rockers hit the sides depending on the rockers you have.
     
    Bob Lowry and X38 like this.
  6. RmK57
    Joined: Dec 31, 2008
    Posts: 2,181

    RmK57
    Member

    Could The differences in steel to aluminum that is causing a louder or more noticeable tone your not used to hearing. If your covers are taller it would sure amplify the valve train noise also.
     
  7. SS327
    Joined: Sep 11, 2017
    Posts: 1,345

    SS327

    I try for .100 clearance between rocker and cover. Play dough helps me figure it out.
     
    Sporty45 likes this.
  8. I have cast aluminum tall ones on my car, as quiet as a mouse. I have to take them off to add another breather and freshen up the gaskets soon. Possible you have a baffle interference issue?
     
  9. sunbeam
    Joined: Oct 22, 2010
    Posts: 5,766

    sunbeam
    Member

    My advice on crome valve covers Cork gaskets and use 3M weather striping adhesive to glue the gaskets to the covers. You will cuss when you have to remove the gaskets.
     
    lemondana likes this.
  10. 63401nailhead
    Joined: Apr 4, 2008
    Posts: 162

    63401nailhead
    Member
    from DE

    The baffles on the aluminum VCs actually seem shallower than on the cheapie chrome ones. So I would think they sit higher when installed and provide more clearance not less. The baffles needed to be screwed on.
     
    bobss396 likes this.
  11. 1971BB427
    Joined: Mar 6, 2010
    Posts: 7,555

    1971BB427
    Member
    from Oregon

    Since the gaskets you bought are new, and high quality, you can likely remove the covers to check, and they should still seal when reinstalled. The longer you wait, the less likely the gaskets will seal like they will when they're fresh and soft.
     
    nunattax likes this.
  12. Do a sound check like one of the ways suggested. If there's a hot spot where the noise is focused or if the noise is general, coming from everywhere, that should give you a clue about what to look for if/when you open 'em up.
    Loosely formed balls of aluminum foil make good "crush gauges" with no mess. No disrespect to the Play Dough idea...... but who's got a tub of that sitting around?
     
    nunattax likes this.
  13. ekimneirbo
    Joined: Apr 29, 2017
    Posts: 2,956

    ekimneirbo
    Member
    from Brooks Ky

    Loosen the screws slightly in your valve cover and start the engine. If they are tapping the valve cover you should see it move. Might just need to adjust a couple of valves if its not hitting the cover.
     
    Budget36 likes this.
  14. Dick Stevens
    Joined: Aug 7, 2012
    Posts: 3,408

    Dick Stevens
    Member

    The quickest simplest way to check is to pull the valve covers and see if there has been any place that the rockers made contact, you will know for certain within about 15 minutes!
     
  15. nunattax
    Joined: Jan 10, 2011
    Posts: 2,951

    nunattax
    Member
    from IRELAND

    if u stick them to the heads you wont lose oil with the covers off.if u jack the car on the side you are removing the covers u wont lose any oil at all,dribbling down the head and on to the exhausts.
     
  16. nunattax
    Joined: Jan 10, 2011
    Posts: 2,951

    nunattax
    Member
    from IRELAND

    the baffles are between the rockers
     
  17. It's a good idea to check online before you buy for reviews that buyers have already posted.
     
  18. jaracer
    Joined: Oct 4, 2008
    Posts: 1,709

    jaracer
    Member

    If it had something to do with the valve covers, I would think it would do it all the time not just under load. That is; unless the valve covers are hitting something when the engine torques over.
     
    ClayMart and Budget36 like this.
  19. spanners
    Joined: Feb 24, 2009
    Posts: 1,627

    spanners
    Member

    Anyone with young Grandchildren has and it's usually stuck to freshly painted bedroom walls and carpet.
     
    SS327 and Sporty45 like this.
  20. 63401nailhead
    Joined: Apr 4, 2008
    Posts: 162

    63401nailhead
    Member
    from DE

    Good point, yeah I don’t notice it when idling in park.

    I did pour a can of sea foam in the crankcase and drove it probably about 25 miles just before the last oil change, which was right when I swapped the valve covers. Crap I hope the seafoam didn’t screw anything up. I’ve used that stuff for years in the gas tank and intake of various cars, but never in the crankcase. Figured it’d be fine for just a few miles.
     
  21. SS327
    Joined: Sep 11, 2017
    Posts: 1,345

    SS327

    WallMart has lots of Play-Dough and it’s cheap!
     
  22. lippy
    Joined: Sep 27, 2006
    Posts: 6,280

    lippy
    Member
    from Ks

    They just look at me weird. Course they all look at me that way. :D
     
    bobss396 and SS327 like this.
  23. I just bought a shallow baffle for a breather that I have to install soon. I'm going to mirror the location from the other cover. I'll probably pop rivet this one in place and did the rivet in sealer (wet install) first.
     
  24. sunbeam
    Joined: Oct 22, 2010
    Posts: 5,766

    sunbeam
    Member

    If you can hear it you should be able to feel it just put you hand on the covers Did you ever put a stock SBC cover on upside down?
     
    Center of the Galaxie likes this.
  25. Have you seen any witness marks inside the valve covers or on the rocker arms indicating contact between them? Do you have solid or hydraulic lifters?

    Do you have a working PCV system or just a couple of open breathers in the valve covers? With a PCV system you may have a PCV valve making a rattling or tapping noise under certain vacuum (engine load) conditions.

    Are you running a mechanical fuel pump? The pump lever can wear or the pump push rod can get sticky in its bore and make a tapping noise. I suppose it might even be more noticeable under heavier engine load conditions.
     
    olscrounger likes this.
  26. ekimneirbo
    Joined: Apr 29, 2017
    Posts: 2,956

    ekimneirbo
    Member
    from Brooks Ky

    Try Hobby Lobby. I bought a box with a block of clay in it. Think it was about $10
     
  27. nunattax
    Joined: Jan 10, 2011
    Posts: 2,951

    nunattax
    Member
    from IRELAND

    most of the time when im looking for stuff for the 38 i get the funny looks too oddball imperial sizes and threads and spanners ,old fashioned oils and fluids ,normal stuff to me.
     
  28. nunattax
    Joined: Jan 10, 2011
    Posts: 2,951

    nunattax
    Member
    from IRELAND

    you could put the play dough between some cling film and turn the engine over slowly
     

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