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Dry stump engines

  1. Mar 22, 2004 #1
    hey everyone, i was wondering if anyone knows how to convert a regular (wet stump) engine into a dry stump engine? Is it hard to do, and is it worth the gain? My goal is to make a low budget, street legal car that can do drag strip duty on the weekends. I know that a dry stump would be better because you can repositon the weight of the oil to make the car have better weight distrabution, but thats about all i know. any comments would be helpful.

    thanks, brian
  2. jcsd
  3. Mar 22, 2004 #2
    The long and short of it is it's tough, and slightly expensive for minimal returns.

    You need a windage tray, crank scrappers, An external oil pump, a resevior for the retorn oil, and a hydraulic accumulator (to act as a surge volume). Add in the AN fittings, braided hose, and the hassel associated. It's not worth it for a weekend warrior.
  4. Mar 23, 2004 #3
    ok, i got another question, would a windage tray be benificial in a regular wet stump engine? and also, is it good to have a negative crank case pressure? If its good to have a negative crank pressure, is that more benificial in a car that has boost?
  5. Mar 23, 2004 #4


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    Dry sumps are expensive, don't kid yourself. The gain isn't in weight distribution, the biggest gain is in having full oil pressure at startup and at any g-load on the motor. As said, very expensive for gains, but when you have 10K in the motor its worth it to protect your investment.

    I've read that a windage tray can be up to maybe 10HP along with knife-edged crankshafts, and both reduce the chance of oil foaming should it puddle and become agitated. Some trays can also help tie the main caps together, I think in top fuel its cross-bolted as well.

    If you had positive crankcase pressure, you would likely have oil leaks around your main seals. Hence the PCV valve....

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