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Intake passages in heads

Discussion in '3rd Gen 4Runners (1996-2002)' started by CoolToyota, May 12, 2024.

  1. May 12, 2024 at 5:03 PM
    #1
    CoolToyota

    CoolToyota [OP] New Member

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    Tore down my engine to fix some oil leaks and pulled the intake and wonder if I should be concerned if anything to do about the buildup !

    IMG_1019.jpg
     
  2. May 13, 2024 at 10:30 AM
    #2
    Airdam

    Airdam New Member

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    there is pretty much nothing you can do for it except the fancy media blast walnut shell machines. They hook over the intake and blast walnut shells in the intake runners and vacuum it out as it sprays to clean the gunk out of the intake runners. I have seen videos of it but honestly unless you put the crankcase vent on a catch can, its going to continue to gunk up again. 99.98% of drivers have no clue about gunk in an intake and dont know how to fix or prevent it, so nobody does anything about it. Its not hurting anything other than cosmetics at the point where you are at.
     
  3. May 13, 2024 at 6:24 PM
    #3
    CoolToyota

    CoolToyota [OP] New Member

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    Ok sounds good !
     
  4. May 13, 2024 at 6:26 PM
    #4
    CoolToyota

    CoolToyota [OP] New Member

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    Is this what a catch can is ?
    https://www.amazon.com/dp/B08LN4GHLP
     
  5. May 13, 2024 at 7:05 PM
    #5
    Airdam

    Airdam New Member

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    yes that is a catch can
    what its job is, is to catch the offgassing fumes and vapors from the crankcase and let it collect in the can, rather than going down the throat of your engine.
    Lotta people dont realize how or why the vapors happen so i'll try to enlighten you.
    1) Any and every oil, or petroleum based product offgasses as it gets hot. Depending on what the product is, the offgas temp changes. I dont know the exact temp for engine oil but i would bet around 150 degrees its offgassing. As the molecules get hot, the produce a gas, that gas has to go somewhere otherwise it would build up inside the crankcase and blow seals out. Interesting solution, they plumb it back into the intake so your engine can breathe it and hopefully burn it to meet emissions.
    2) engines with age and lots of miles have poor compression, as the piston nears TDC TopDeadCenter, and the piston is compressing the air in the cylinder, with poor cylinder walls or rings you can lose some of this compression "pressure" past the rings where it gets pushed down into the crankcase. This causes crankcase pressure which has to find a way out, and it does thru the crankcase vent tube routed into your intake.
    When you combine an offgassing oil in the crankcase plus some compression / blow-by in the crankcase, you get a crap ton of fumes and oil vapor blown up into the intake. A catch can helps collect this oil and allows it to drip down into the can so you can drain it later. I typically put a small valve on them and run a hose down by the oil pan so the catch can is easy to drain every oil change. The catch cans have a baffle where as the vapor is coming in, the vapor hits a small wall inside the can, this causes the oil vapor to hit this wall and stick, and then drip down. Its pretty simple but it works. Older engines with a lot of blow-by will puke up a bunch of oil. Boosted engines also puke up a bunch of oil and need a catch can.
     
  6. May 13, 2024 at 8:49 PM
    #6
    SR5 Limited

    SR5 Limited New Member

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    It may increase air-flow by constricting it a little. Thats how a venturi wotks. And anyways the metal is not smooth undrr there. Its rough to get a proper fuel-air mixture.
     
    CoolToyota[OP] likes this.
  7. May 14, 2024 at 12:39 AM
    #7
    CoolToyota

    CoolToyota [OP] New Member

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    That is very helpful and clear - thanks everyone
     
  8. May 14, 2024 at 10:00 AM
    #8
    ChessGuy

    ChessGuy New Member

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    Too many..... Performance: • Magnusum Supercharger • Gibson exhaust with dual black tip • Pedal Commander * PowerBrakes • Suspension – Old Man Emu BP-51 front and back with Medium load coils • Tires: AT3 Faulken Wildpeak – 285/70/17 • Wheels: Relations Race Wheels, RR7-H with -12 offset • Full roof rack and ladder by Westcott Design (removed the stock Yakima basket) • Molle storage panels by Rago fabrication • Front light brackets by Rago • Illuminator light bracket by Rago (roof rack location) Lights • Morimoto front and back with sequential signals • Morimoto fog lights and side mirrors with sequential signals • 40” Baja design light bar for roof rack • 20” S8 Baja design driving combo (winch location) • Squadron sport baja design ditch lights • S2 Chase lights by baja designs (mounted on roof) In the bay: • Odyssey 34-PC Battery • SDQH Aluminum billet battery terminals and bracket • Switch Pro 9100 with aluminum tray • Anytime front and back camera • ARB twin compressor Recovery & Protection: • Smittybilt X20 synthetic rope winch • Factor 55 fairlead and flatlink • Southern Style Off-road (SSO) low profile bumper • SSO stage 2 high clearance wings • Weekend warrior recovery kit by treaty oak • RCI – skid plates – entire vehicle + catalytic converter protection wings Interior: • Nano Ceramic IR – Avery Dennison Window tint – all windows • Several phone mounts • Upgraded Rear Hatch lift gate struts (ladder is heavy) • Boom blaster horn switch (featuring La cucaracha)
    I was thinking of that same thing. Sand blast this somehow....but but be very careful else you will chip edges and create other issues.
     
  9. May 14, 2024 at 10:03 AM
    #9
    CoolToyota

    CoolToyota [OP] New Member

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    Leave well enough alone !
     
    negusm and backpacker like this.

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