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Thread: cam timing

  1. #1
    West Texas RXP skoepp's Avatar
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    cam timing

    I was messing with the cam tonight and changing it per visual in crank hole and now got some questions.

    Doing some research and looking for any info on retarding and advancing the cam.
    Mainly looking for info on retarding the 04 - 29 cam.


    Thanks


  2. #2
    Richieb's Avatar
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    Sounds like dangerous ground to me. Twin Cams You can play with, but SOHC, its a minefield. I think someone did a big tech write-up on here about it.
    Advance the inlet... retard the exhaust.

  3. #3
    The most interesting man in the world. Nils888's Avatar
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    Quote Originally Posted by skoepp View Post
    I was messing with the cam tonight and changing it per visual in crank hole and now got some questions.

    Doing some research and looking for any info on retarding and advancing the cam.
    Mainly looking for info on retarding the 04 - 29 cam.


    Thanks
    You can go 2 degrees in each direction. Advancing will bring the power band down. Retarding it will move it up.

    I would leave it in the stock location!

  4. #4
    Focker Foggy's Avatar
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    In my automotive experience, being able to retard or advance
    the cam 2* provides such negligable results that its just
    not worth wasting even 5 minutes to do it..
    I don't know the piston/valve clearance on the 4 tecs, so
    I personally wouldn't change it at all. If you want to move
    the powerband up, you will just have to get a bigger cam.

  5. #5

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    from full advance to full retard within the factory slotting makes a substantial change in performance. On a high boost turbo app. it is worth a few hundred rpm fully retarded. I just spent last Saturday making the changes back to back, with good data logging. I cannot say if a supercharger will yield the same result. Go fully retarded, and see for yourself. With standard cams there is plenty of room, and you actually move the intake valve further into the "green" zone when you retard. Post your results when you try it.

  6. #6

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    and realize that from center to full retard is appx. 2 deg, which is 4 deg. full advance to full retard, which is 8 deg of crank rotation. This is a very big change, you will see a difference.

  7. #7
    speedskixp's Avatar
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    And I though you guys were all already fully retarded.
    Seriously though we have seen 100+rpm difference just from playing with the cam timing.

  8. #8

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    at what boost level did you see the 100+ if I may ask? and what was peak RPM?

    With turbo I saw 8150 at 20psi (turning a big prop and pump) advanced, and 8325 at the same 20psi fully retarded, zero other changes.

    Almost a 2mph difference in top speed. but a loss of about .3 of a second of boost response time. everything has it's price..

    Louis

  9. #9
    West Texas RXP skoepp's Avatar
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    thanks for the replies, and keeping coming. I have heard of some other cases of big difference in rpm. I need to find time to changing the timing on the water.

  10. #10
    i run all my stuff fully retarded

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