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5 Angle Valve Job

Discussion in 'Engine Building' started by BigJ, Feb 28, 2003.

  1. BigJ

    BigJ I'm just about that action Boss. VIP

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    Hey my buddy just got quoted from a local building shop on 150 for a 5 angle valve job. What exactly is it? and what will increases be? He is going to be putting a vtec head and building his b18a1 soon and wants to know if it is worth it for the extra 150 for it.
     
  2. saturn_boy96

    saturn_boy96 88 C1V1C 53D4N DR1V3R

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    some body with paint shop draw this kid a picture for me.

    basically they just contour the angles on the backside of the valves and contour the angles on the openings of the valvesin the combustion chamber.

    not sure what the actual angles are on a 5-angle job but on a 3 angle its 30-45-60. i am not sure if it is worth it though cause honda heads come from the factory with a mild 3-angle already.

    not sure on that last bit though. my $02
     
  3. cws13

    cws13 Senior Member

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    A five angle valve job cuts five angles into the valve/valve seat. A valve job like that improves sealing in the cylinder head for one. Secondly, air begins to tumble over about 35 degrees of pitch and wipes out the possibiblity of a nice tulip (swirl of atomized air/fuel) for the best combustion and flame front propegation across the piston when the spark lights it off. When boosting a motor the air is already too turbulent for this tulip, but you are running over 100% volumetric effeciency and that makes up for it, so at that point it is about sealing in all of that pressure. Yes it helps, a shop should be able to help you determine how agressively you need to work over the head. As long as it is off, I would look into mild porting, port matching, and polishing. You will get nice gains from the total package. Don't let a domestic machinest work over your head!!! They will want to hog out your ports like old Domestics and your car will run like shit below 6 grand. Hope this helps.
     
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