Cam Timing question
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Cam Timing question

  1. #1
    Senior Member ol guy's Avatar
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    Default Cam Timing question

    Okay lets say you are playing with cam degree numbers. You set cam at spec and feel like going 4 degrees one way or the other. Which will give you more valve clearance and which way for less? Just curious. M

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  3. #2
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    Advancing tightens the intake clearance. Retarding tightens exhaust clearance.
    Rule of thumb large roller cam BBC about .007 per degree (280 ish duration at .050).

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    Quote Originally Posted by Fiat48 View Post
    Advancing tightens the intake clearance. Retarding tightens exhaust clearance.
    Rule of thumb large roller cam BBC about .007 per degree (280 ish duration at .050).
    Okay I see what you are saying but what if it would be a 240 @ .050 and you are hazing the exhaust valve and back of 4 degrees. what would that do! M

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    What about on a blown engine? I have heard that advancing the cam 5 degrees will allow the engine to make more boost?

    Any truth to that?

    Thanks

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    Wrong way.
    Advance the cam and it will give the exhaust more clearance.....but tighten the intake clearance. Advancing will tighten the intake P/V clearance "X" amount.....and will loosen the exhaust clearance "x" amount.

    I think you better check P/V clearance if you are "hazing". Also check valve springs.
    Last edited by Fiat48; 08-04-2011 at 08:05 PM.

  8. #6
    Senior Member ol guy's Avatar
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    Quote Originally Posted by Fiat48 View Post
    Wrong way.
    Advance the cam and it will give the exhaust more clearance.....but tighten the intake clearance. Advancing will tighten the intake P/V clearance "X" amount.....and will loosen the exhaust clearance "x" amount.

    I think you better check P/V clearance if you are "hazing". Also check valve springs.
    Thank you for easing my mind! for a while I was spinning around in my head which way to go and I think everybody has over thought a problem. Just for your'e info when I degreed the cam in it took 4 degrees to match the numbers on the retard side. Now I am going to a zero setting which will open up the exhaust clearance to be safe and probably I will loose the lazy response (throttle) I have now. Thanks again! M

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