Timing ?'s
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Timing ?'s

  1. #1
    Senior Member 2savage4you's Avatar
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    Default Timing ?'s

    When i first put the engine in the boat i dropped the dizzy in at 18*'s BTDC and if the fuel is primed she will fire on a bump.

    Went out today to start her and now she want's to run rough checked the plugs and they are BLACK!!!

    I had 92-94 jets in the carb but swapped them out to 84 squared. i don't think it matters at this point but thats the only thing i have done since i got her to run, i have not even timed it can't find my light

    Where is a good point to start from when timing ? should i move the dizzy to tdc? or time from where i am now.

    this is a BBC 454 im working with, i should probably get her in the water first and go from there but i just want to make sure im in the ball park.

    BBC 454
    Holley 850 annular carb
    Clay Smith cam Solid flat tappet
    Cam #'s 304 [email protected]
    106 lc
    .615 lift
    Mallory elect ign (Locked out)
    Last edited by 2savage4you; 06-16-2009 at 02:45 PM.

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  3. #2
    Choking my ....... beerjet's Avatar
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    Dizzy back at zero, eh.....
    36 degrees of total timing
    Love aint nothing but a four letter word, just like f*ck and sh!t .

  4. #3
    Senior Member H20MOFO's Avatar
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    If you ARE locked out I'd start her at 34-35ish.
    Another Hot Boat refugee

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  6. #4
    Sit N' Spin Jetaholic's Avatar
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    Quote Originally Posted by 2savage4you View Post
    When i first put the engine in the boat i dropped the dizzy in at 18*'s BTDC and if the fuel is primed she will fire on a bump.

    Went out today to start her and now she want's to run rough checked the plugs and they are BLACK!!!

    I had 92-94 jets in the carb but swapped them out to 84 squared. i don't think it matters at this point but thats the only thing i have done since i got her to run, i have not even timed it can't find my light

    Where is a good point to start from when timing ? should i move the dizzy to tdc? or time from where i am now.

    this is a BBC 454 im working with, i should probably get her in the water first and go from there but i just want to make sure im in the ball park.

    BBC 454
    Holley 850 annular carb
    Clay Smith cam Solid flat tappet
    Cam #'s 304 [email protected]
    106 lc
    .615 lift
    Mallory elect ign (Locked out)
    Did you take the power valve out of the carb? If so, did you plug it off with the screw in power valve plug?

    If not running the power valve, a power valve plug MUST be installed (otherwise it's like running with the power valve open at all times, causing an over rich condition).

    Square jetting a carb is done ONLY when you're not running a primary power valve, OR if you're running a power valve in both the primary and secondary metering blocks.

    The purpose of the power valve is to allow you to run much smaller jets in the primary for economy purposes. When extra fuel is needed (signaled by a vacuum signal that is lower than the power valve's rating), the power valve opens and allows extra fuel from the bowl to bypass the jets and flow into the main wells. This is why most Holleys that run a power valve in the primary but not the secondary come stock with primary jets that are 8-10 sizes smaller than the secondary jets, even though the carburetor bores are of equal size (squarebore carbs). Carbs with both a primary and secondary power valve are square jetted small whereas carbs without a power valve at all are square jetted big.

    If your carb still has a power valve, either pull it and install a power valve plug, or reduce the primary jets by 8-10 sizes. Otherwise, you'll be WAY too rich, causing the overrich condition on your plugs.

    My personal opinion - on an all out race or circle boat, I can see a point to removing the power valve and square jetting the carb. Most race/circle boats are at WOT most of the time...you need all the fuel you can get in most cases. However, for a lake cruiser that will see the occasional WOT passes but mostly part throttle driving, there's absolutely no point to removing the power valve and square jetting (no need for it) and you'll be way down on fuel economy as a result.
    Last edited by Jetaholic; 06-16-2009 at 04:43 PM.



    Quote Originally Posted by HammerDown
    Kendall L-427 Super Blu...extreme-pressure (ep) lithium complex keeps my thrusting balls happy
    Quote Originally Posted by back2k5 View Post
    Well I am putting in a nice stereo system in the Carrera...maybe Ill put on some rap and turn the scoop sideways

  7. #5
    Senior Member 2savage4you's Avatar
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    I can drop my primarys down to 80 (78 is stock jetting ) These were jetted @ 92 primary and 94 secondary and ran on a BBC 460 with no prob

    I have already dropped down in jet size and a few people have told me to square off??

    so ill give that a try

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    I would set the timing at 38 total!!80 primary 84 sec and let it rip!

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    Senior Member H20MOFO's Avatar
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    Will timing effect how a plug reads???
    Last edited by H20MOFO; 06-16-2009 at 06:31 PM. Reason: Should have read orig. post better
    Another Hot Boat refugee

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    Sit N' Spin Jetaholic's Avatar
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    Quote Originally Posted by H20MOFO View Post
    He says he is set at 18* and he is locked out.......or did I read something wrong. My first response was to say what does timing have to do with plugs. But I guess if you are running at 18* that might...I dunno..
    What does timing have to do with plugs? Timing is what controls when the plugs fire.

    Will timing affect how a plug reads? Yes and no.

    Timing will discolor a certain area on the ground strap. If your timing is correct, the ground strap should have this discoloration on the curved part of the ground strap. If it's closer to the threads, this means it's too advanced. Closer to the tip, it's too retarded.

    The black color on the plugs indicate that he's over rich.
    Last edited by Jetaholic; 06-16-2009 at 06:35 PM.



    Quote Originally Posted by HammerDown
    Kendall L-427 Super Blu...extreme-pressure (ep) lithium complex keeps my thrusting balls happy
    Quote Originally Posted by back2k5 View Post
    Well I am putting in a nice stereo system in the Carrera...maybe Ill put on some rap and turn the scoop sideways

  11. #9
    Senior Member H20MOFO's Avatar
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    Quote Originally Posted by Jetaholic View Post
    What does timing have to do with plugs? Timing is what controls when the plugs fire.
    So more advance will read/be leaner???
    Another Hot Boat refugee

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    Sit N' Spin Jetaholic's Avatar
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    Quote Originally Posted by H20MOFO View Post
    So more advance will read/be leaner???
    No.

    Timing and mixture have nothing to do with each other.

    If you're over rich, it may be impossible to see the discoloration on the ground strap from where the spark hits it. Timing is only indicated on the ground strap only.

    Mixture is read on the pocelain tip of the plug. Black indicates rich, white indicates lean.



    Quote Originally Posted by HammerDown
    Kendall L-427 Super Blu...extreme-pressure (ep) lithium complex keeps my thrusting balls happy
    Quote Originally Posted by back2k5 View Post
    Well I am putting in a nice stereo system in the Carrera...maybe Ill put on some rap and turn the scoop sideways

  13. #11
    Sit N' Spin Jetaholic's Avatar
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    2sav, can you post up the part number on your carb (located on the choke horn, should be a part number that looks something like R-80xxx)? I'd like to look it up in my Holley book and find out exactly what came in it stock.



    Quote Originally Posted by HammerDown
    Kendall L-427 Super Blu...extreme-pressure (ep) lithium complex keeps my thrusting balls happy
    Quote Originally Posted by back2k5 View Post
    Well I am putting in a nice stereo system in the Carrera...maybe Ill put on some rap and turn the scoop sideways

  14. #12
    Senior Member 2savage4you's Avatar
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    Before we get carried away , I WAS running bigger jets but downsized them. I didn't change or clean the plugs so we can't tell if im rich or not till i do.....

    I need to fix timing first then run it and go from there

  15. #13
    Senior Member 2savage4you's Avatar
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    Quote Originally Posted by Jetaholic View Post
    2sav, can you post up the part number on your carb (located on the choke horn, should be a part number that looks something like R-80xxx)? I'd like to look it up in my Holley book and find out exactly what came in it stock.

    http://www.holley.com/0-9380.asp


    (Stock) 9380 850 (F)78,(R)78 6.5,6.5 4150

  16. #14
    Sit N' Spin Jetaholic's Avatar
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    Quote Originally Posted by 2savage4you View Post
    http://www.holley.com/0-9380.asp


    (Stock) 9380 850 (F)78,(R)78 6.5,6.5 4150
    OK that's a dual power valve carb. I would go back to stock and start from there. Also, check your idle mixture settings too.

    All checks should be done with the boat on the water under load, otherwise your vacuum readings will be inaccurate (vacuum readings are a direct indication of engine load).

    If you don't have a vacuum gauge, get one and hook it up to manifold vacuum and find out what your idle vacuum is. Stock power valves in this carb are 6.5 (meaning they open at less than 6.5" of vacuum). Assuming you don't have any vacuum leaks (a vacuum leak will cause the power valves to hang open, causing an over rich condition), if your idle vacuum is less than double this value, downsize the power valves with a size that is half your idle vacuum (if idle vacuum is 10", downsize to a 5.0 power valve).

    Does this carb have 2 or 4 idle mixture adjustment screws?

    Also, can you post up the valve timing from the cam card?
    Last edited by Jetaholic; 06-16-2009 at 07:05 PM.



    Quote Originally Posted by HammerDown
    Kendall L-427 Super Blu...extreme-pressure (ep) lithium complex keeps my thrusting balls happy
    Quote Originally Posted by back2k5 View Post
    Well I am putting in a nice stereo system in the Carrera...maybe Ill put on some rap and turn the scoop sideways

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