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1.9L ls/vtec blow by issues?

Discussion in 'Engine Building' started by Somalia757, Jul 8, 2008.

  1. Somalia757

    Somalia757 SOMALIA

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    I have a ls/vtec that was balanced and blue printed, with oversized b16 pistons and bored out a tad to make it 1.9L.
    The head was not rebuilt from the looks of the seals. I noticed a leak in the vtec silenoid gasket and the cam seals are seeping a bit. My question is since the motor has 15K on the bottom end is the head whats causing the oil to blow by past the valve guides/valves into the combustion chamber? What do I need to do to pinpoint the problem. I want to go turbo soon so I want to figure out if the head needs all the gaskets and shit replaced or do a whole rebuild.
    Thanks somalia.
    My engine builder told me to checl the pvc valve first and see if it needs to be replaced, but he said its proably just blow by because of the high pressure during vtec, and its ONLY during vtec when this is happening.
    How do I pinpoint the problem? Compression test? Leakdown?
     
  2. newb

    newb phresh VIP

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    If Im not mistaken blow by is when the combustion charge pushes past the rings into the crank case, not when oil pushes past the rings into the chamber. A leakdown test is deffinitly a good place to start to see what kinda shape some of the internal parts of you engine are in.
     
  3. Slow&Delirious

    Slow&Delirious isn't fast or furious

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    if it is blow by, then i would think the pistons are not tight like they should be. Maybe is is possiable that it was overbored or the wrong kind of rings ect.

    this is the reason i would be extremely cautious when boring out a block
     
  4. t3t4delsol

    t3t4delsol New Member

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    how milky is the oil and is the exhaust smoking? the pcv valve is a good place to start because its cheap, pull it out and shake it to see if it still rattles. If it rattles freely its still good. If its not rattling its time to replace it, The pcv valve helps with crankcase ventilation and can very well cause blow by if your creating alot of pressure in the bottom end.
     
  5. boostin4fun

    boostin4fun Boosted ls/vtec ohh yeah!

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    Not having a adequate breather setup could be your problem but I would definetly do a leak down test. Here is a link to the best b series breather setup, this is what I use and I have zero problems with my boosted ls/vtec. The Old One - Energy Dynamics : Recommended Components
     
  6. Somalia757

    Somalia757 SOMALIA

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    The oil isn't milky at all that's the 1st place I started because I thought maybe the headgasket was bad. The exhaust does smoke black and a bit of white
     
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