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Thread: V8s and V6s and oil control

  1. #1
    Senior Member robburgoon's Avatar
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    Default V8s and V6s and oil control

    When you have a v8 or a v6 with a 90* angle between the cylinder banks, you end up with the cylinder heads bolting onto a surface that is 45* off of vertical.

    If the cylinder head is rectangular shaped, then the top of the head will be 45* off of vertical.

    Now, if your car generates 1 lateral G in the corner, that combines with gravity to create a net force that is 45* from straight down. This force will pull oil straight down through the drain holes in the head for one head. That's good.

    The head on the outside of the corner, the side of the valve cover becomes "down" for as long as the car is in the corner.

    Doesn't seem all that surprising that v8s like to blow up.

    Suddenly inline engines start looking a bit more appealing for the much easier oil control...

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    Senior Member fatbillybob's Avatar
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    Isn't it all about engineering design? The v8 van survive quite nicely at high g load like around 4gs and 10k+ rpm on pro race motors. Our modified street motors do fine with things like good general design sometimes user addition of drysumps od various scavenging stages or additional oil volume or baffled oil pans and modified oil pumps. While the initial fixes are experimental the aftermarket so figures it out and we just blindly follow the recipe.

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    Senior Member robburgoon's Avatar
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    Quote Originally Posted by fatbillybob View Post
    Isn't it all about engineering design? The v8 van survive quite nicely at high g load like around 4gs and 10k+ rpm on pro race motors. Our modified street motors do fine with things like good general design sometimes user addition of drysumps od various scavenging stages or additional oil volume or baffled oil pans and modified oil pumps. While the initial fixes are experimental the aftermarket so figures it out and we just blindly follow the recipe.
    I wonder if the basic dry sump simply has a reservoir so big that it's able to brute force the solution. So much oil on reserve that its able to outlast the design flaw. Then when you stop turning all the oil will quickly drain and get your safety margin back.

    Also, some dry sump systems will scavenge from the cylinder heads too I think.

    My point is it's gotta be easier to get a inline to continue to function with a wet sump since oil doesn't have such an easy time getting trapped.

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    Administrator ucfbrett's Avatar
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    Anytime you have high horsepower and high g loads, even with inline engines, dry-sump oiling becomes necessary. Scavenging pump chambers outnumber pressure chambers on fours and sixes like any V-design engine.

    Dry sumps keep a large volume of oil in reserve so that the pressure chamber is never starved for oil and thus the engine is never starved. The V-8, in pushrod form, is as much about packaging as it is about power. It's an efficient design that fits in a lot of places, and it's largely why we don't have straight eights anymore. As soon as the V8 became common, straight eights disappeared.

    We still have inline sixes because they're still small enough to fit in contemporary engine compartments.

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    Senior Member robburgoon's Avatar
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    Quote Originally Posted by ucfbrett View Post
    Anytime you have high horsepower and high g loads, even with inline engines, dry-sump oiling becomes necessary. Scavenging pump chambers outnumber pressure chambers on fours and sixes like any V-design engine.

    Dry sumps keep a large volume of oil in reserve so that the pressure chamber is never starved for oil and thus the engine is never starved. The V-8, in pushrod form, is as much about packaging as it is about power. It's an efficient design that fits in a lot of places, and it's largely why we don't have straight eights anymore. As soon as the V8 became common, straight eights disappeared.

    We still have inline sixes because they're still small enough to fit in contemporary engine compartments.
    Sure, but if you're gonna wet sump it, maybe inline is safer

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    Administrator ucfbrett's Avatar
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    Sure, go win in your Modified with a six.

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    Senior Member robburgoon's Avatar
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    Quote Originally Posted by ucfbrett View Post
    Sure, go win in your Modified with a six.
    Nah, no forced induction or N2O allowed. Besides, larger capacity wet sump oil pan design is pretty well figured out for circle track. Although, wouldn't you know it, there's no breathers on the right side valve cover.

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    Administrator ucfbrett's Avatar
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    Hillbilly engineering for the win.

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    "Shoe"
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    I wonder how wet sump'd circle track cars work?!?!?!?!

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    Administrator ucfbrett's Avatar
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    Quote Originally Posted by Stuntman View Post
    I wonder how wet sump'd circle track cars work?!?!?!?!

    Big pans with lots of capacity, offset sumps and no breathers on the "outside" cylinder bank.

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    Senior Member robburgoon's Avatar
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