Zoomie Length?

Discussion in 'Manton Push Rods Top Alcohol Tech Questions' started by Bjs344, Oct 26, 2013.

  1. Bjs344

    Bjs344 Member

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    I have an old set of downswepts that need retired, thought about cutting them up to build zoomies. How short is too short? What is the risk of going too short? BBC conventional head with a 14-71hhr making around 20 psi on a 584.
     
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  2. Mike Canter

    Mike Canter Top Dragster

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    No risk as far as I have ever been told. On a blown motor the idea is to get as much exhaust out as fast as possible and clear the body or what ever is in the way.
     
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  3. hemi altered 378

    hemi altered 378 Blown Altered

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    i think most are around 19"......the last set i built for my car were 19.5. it depends on your combo. longer tubes (to a point) will up the torque.
    Darren
     
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  4. Bjs344

    Bjs344 Member

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    Thanks. I was thinking ~14". Way more torque than I can use in the first 30' rigt now.
     
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  5. Eric David Bru

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  6. aj481x

    aj481x Member

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    Somebody will have a theory why these are too long. ;)
     
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  7. Critical Mass

    Critical Mass Member

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    I have heard if they are to short you may get some warped valves? I don't know if this is a possibility or not; I have never experienced it.
    Joe
     
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  8. Bjs344

    Bjs344 Member

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    I've heard this too, never been sure if it's just an old wives tale? The ones in Erics picture
    Are about what I was thinking.
     
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  9. Blownalky

    Blownalky Top Sportsman

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    Exhaust valves would warp if the valve was in contact with cold air. Would normally happen when you had a crack in the manifold or header and then the engine was stopped and the valve was hanging open. Saw it several times and I could see that happening if you shut a motor off with stubby headers but it would probably have to be pretty cold like in the 30's or below.
     
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  10. Soldierboy0098

    Soldierboy0098 Active Member

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    Zoomies

    Mr. Bob Ginther of the Blue Angel Engineering TAD once told me he tested with several different lengths, most of witch are still laying on his shelves. In the end he saw no difference other than weight and now runs some very short units just enough to make a turn up, maybe 8"-10" long or so. He is on here and could be asked.

    Best wishes,
    Trevor Sherwood
    727-364-4368
     
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