boost gauge fluttering
+ Reply to Thread
Page 1 of 4 1 2 3 4 LastLast
Results 1 to 14 of 49

Thread:
boost gauge fluttering

  1. #1
    Senior Member
    Join Date
    Feb 2009
    Location
    SF Bay Area
    Posts
    204

    Default boost gauge fluttering

    Anyone know what would make the boost gauge flutter? Only does it in boost, not vacuum, and gets worse as pressure goes up. Needle had always been stable at any pressure. Compression is good, all cylinders within 1 to 2 lbs.

  2. Remove Advertisements
    PerformanceBoats.com
    Advertisements
     

  3. #2
    Senior Member 67weiman's Avatar
    Join Date
    Dec 2007
    Location
    Surprise, AZ
    Posts
    985

    Default

    Boost leak? Bad gauge?

  4. #3
    Senior Member
    Join Date
    Feb 2009
    Location
    SF Bay Area
    Posts
    204

    Default

    Yeah, maybe the intake manifold gasket let go; the gauge's hose is tapped in near cylinder #7.

  5. Remove Advertisements
    PerformanceBoats.com
    Advertisements
     

  6. #4
    Senior Member wizbang's Avatar
    Join Date
    Feb 2008
    Location
    Kent, WA
    Posts
    1,485

    Default

    Blower base gasket, o-ring or pop off plate ?

  7. #5
    LP-25.com Infomaniac's Avatar
    Join Date
    Dec 2007
    Location
    New Port Richey, FL
    Posts
    16,855

    Default

    How close to the valve is the port?
    If For Some Reason I Do Something Worthy Of Recognition. God Provided The Ability And Deserves The Credit.


    QE 439 Twin Turbo

  8. #6
    Ain't Right Racin piston in the wind's Avatar
    Join Date
    Dec 2010
    Location
    Sapulpa ok
    Posts
    1,706

    Default

    Check valve springs ??
    QE 2050 W/ a Junk ass screw blower

    90% of the game is half mental... The pursuit of the unknown is priceless & gratifying . Sometimes it just takes good old fashion balls. No amount of reasoning or evaluation can deem it right or wrong. At the end of the day stick with whatever gives the person in question morning wood LOL

  9. #7
    Senior Member
    Join Date
    Feb 2009
    Location
    SF Bay Area
    Posts
    204

    Default

    Quote Originally Posted by Infomaniac View Post
    How close to the valve is the port?
    A couple of inches from the cylinder head. The gauge's needle has been stable for nearly 200 hrs (3 engines).

  10. #8
    Senior Member
    Join Date
    Feb 2009
    Location
    SF Bay Area
    Posts
    204

    Default

    Quote Originally Posted by piston in the wind View Post
    Check valve springs ??

    Will do, was going to check the lash anyway.

  11. #9
    Senior Member
    Join Date
    Feb 2009
    Location
    SF Bay Area
    Posts
    204

    Default

    Quote Originally Posted by wizbang View Post
    Blower base gasket, o-ring or pop off plate ?
    I think I will change the blower while its apart anyway; I will check the pop off plate and gasket.

  12. #10
    gn7
    gn7 is offline
    Senior Member gn7's Avatar
    Join Date
    Jan 2008
    Posts
    25,975

    Default

    If this is new phenom on an existing engine. I doubt its the location of the line in the manifold.
    A leaking pop off or base gasket is nothing more than a leak, not unlike a open intake valve, but constant instead of cycling. A leaking pop off or base gasket would only smooth out any pulsing in the manifold, not increase it.

    However, leaking or bouncing intake valves are another story. Just one badly leaking intake can create pretty severe manifold pressure spikes.



    100% free webcam site! | Awesome chicks and it is absolutely free! | Watch free live sex cam - easy as 1-2-3

  13. #11
    Senior Member
    Join Date
    Feb 2009
    Location
    SF Bay Area
    Posts
    204

    Default

    gn, what you are saying is what I was afraid of but it has perfect compression in all 8. Maybe a valve spring problem?

  14. #12
    gn7
    gn7 is offline
    Senior Member gn7's Avatar
    Join Date
    Jan 2008
    Posts
    25,975

    Default

    Quote Originally Posted by SFOcean View Post
    gn, what you are saying is what I was afraid of but it has perfect compression in all 8. Maybe a valve spring problem?
    Either valve springs or the lash is really loose the valves are slamming the seats when they close instead the last of the cams closing ramp sitting them down gently.

    What brand/size roots is this thing?



    100% free webcam site! | Awesome chicks and it is absolutely free! | Watch free live sex cam - easy as 1-2-3

  15. #13
    Senior Member
    Join Date
    Feb 2009
    Location
    SF Bay Area
    Posts
    204

    Default

    Blower Shop 8-71 @ 16% over, 6 lbs boost; changing to Blower Shop 14-71 so I can slow the drive down to 5% over and net 10lbs boost. It is intercooled.
    Oh, and the lash was set cold at 12 intake, 16 exhaust 15 hrs ago when the engine was built. Crane wants 18 across hot.
    Last edited by SFOcean; 09-23-2013 at 08:40 PM.

  16. #14
    gn7
    gn7 is offline
    Senior Member gn7's Avatar
    Join Date
    Jan 2008
    Posts
    25,975

    Default

    Quote Originally Posted by SFOcean View Post
    Blower Shop 8-71 @ 16% over, 6 lbs boost; changing to Blower Shop 14-71 so I can slow the drive down to 5% over and net 10lbs boost. It is intercooled.
    Oh, and the lash was set cold at 12 intake, 16 exhaust 15 hrs ago when the engine was built. Crane wants 18 across hot.
    If those settings were done cold, they are probably a little loose hot, specially the exhaust. Alumin heads usually require .006 to as much as .009 tighter than the hot lash.



    100% free webcam site! | Awesome chicks and it is absolutely free! | Watch free live sex cam - easy as 1-2-3

+ Reply to Thread
Page 1 of 4 1 2 3 4 LastLast

Quick Reply Quick Reply

Register Now

Please enter the name by which you would like to log-in and be known on this site.

Please enter a password for your user account. Note that passwords are case-sensitive.

Please enter a valid email address for yourself.

Please select your insurance company (Optional)

Log-in

Tags for this Thread

Digg This Thread

Posting Permissions

  • You may post new threads
  • You may post replies
  • You may not post attachments
  • You may not edit your posts
  •  
 

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95