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  1. #1
    Senior Member thunderracing91's Avatar
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    01.27.03
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    Default Engine freshning?

    I was curious how many hours or races will my 1600 have before it needs gone through again? As it sits right now I only have 4 races on a fresh engine. Can you tell a significant power loss when it is ready to get freshened up or is it pretty gradual? I was just wondering if I will be able to make it through the season to next winter before I would have to pull the engine again....................

    Thanks!!
    Andrew

  2. #2
    Lurker Keith Carter's Avatar
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    Default

    It's a gradual degradation of power. 4 races is still pretty fresh by our standards, we'd still run that thing for a couple more seasons! If in doubt though, have the head freshened mid season.
    2003 VanDiemen FSCCA #29
    Follow me on Twitter @KeithCarter74

  3. #3
    Contributing Member TimW's Avatar
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    Default

    So, head freshening is different than engine freshening, as I understand it. I'm told that 20-25 hours or 2000 or so miles is appropriate for the bottom end. For head freshening, I lap the valves when the leak down tells me to. Probably every 3-4 races though I've heard when FF was ultra competititve it was done after each weekend. For other top end maintenance others tell me they send to their builders between bottem end rebuilds but my builder doesn't want to see the head unless there is a problem or he's just lapping the valves for me which he strongly suggests I do myself.

    I did 8 races and the runoffs t his year and ran a total 820 miles; this however is grossly reduced by all the wet sessions I sat out of this spring or shortened wet races I ran. I've generally budgeted 140 miles per national, 120 per CenDiv double regional.
    ------------------
    'Stay Hungry'
    JK 1964-1996 #25

  4. #4
    Senior Member Ken Rozeboom's Avatar
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    Default

    It depends on what parts were used in building your engine. The new AL head has steel seats which last far longer than the soft (no insert) seats in the cast iron heads. That's where the 1-2 hours between valve jobs came from. I don't know the effective life on the AL head seats because I usually bend a valve first.....

    The new Ivey pistons provide a much longer life than the oem stuff. 20hrs was the accepted time frame but Jay is suggesting 50hrs.

    The SCCA crank is hopefully a long term part. Charlie Williams always replaced my oem crank every rebuild.

    The Kent engine is a much different proposition with the new rules but tradition dies hard.

  5. #5
    Contributing Member bryancohnracing's Avatar
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    Default Your mileage may vary!

    I tend to look at how I've used the engine almost as much as mileage or actual time on the engine. For example, if I have a huge over rev on a downshift, off it goes to Charlie for a rebuild. I'm talking huge like 8000 plus btw...No, I don't make a habit of this!!!

    Head freshening is worth every penny and Charlie's price is very reasonable.

    What I've found is that you can hear a difference in the crispness of the exhaust note when it really needs it. Of course, by then you've waited too long!

    The best way to know is a leak down test; after each race would be best. This way you can chart the changes and you'll know when to do it.

    Have fun in Memphis!

    Bryan
    Bryan Cohn
    bryancohnracing@yahoo.com
    417-540-2595 text

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