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Alexi, I 100% agree. There are a lot of people putting screens in there valley for no reason other that they saw, read or heard it was the thing to do. if you look at the screen it has roughly 50% of the open area of no screen. Like making the slots in the valley half the size. BUT, the screen also adds restriction to flow due to all the added surface area, even it is 50% free area. The only resistance to flow with the stock slots is the perimeter edge. The screen looks plenty big, because its the length of the block, but the actually opening are still just the slots.
I came to the same conclusion you did years ago, and start making my own screens that were domed, or half round, and could flow oil thru them their full length. Did that maybe 2 years, and gave that up as senseless and now run them open, no screen. The idea worked fine and flowed very well. Just not worth the effort.

Thanks for posting that. It is an eye opener and may give some second thoughts about screens.



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steelcomp was here
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That probably wouldn't be so bad once the oil's hot...but add to that crank case pressure trying to come up through that screen, and now you have a problem, no matter how hot or tin the oil.
 

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That probably wouldn't be so bad once the oil's hot...but add to that crank case pressure trying to come up through that screen, and now you have a problem, no matter how hot or tin the oil.
Oil going down dealing with air going up is a major reason I pulled the screens. The more you reduce the area, the more you increase the velocity of the air headed up, all fighting for the same space. Even of you have a Vac system of any sort, if the pan is in a depression, then the blowby had to go up thru the valley to get to that depression. It helps, but the gases are still flowing upward thru those slots.

Want to see the oil REALLY stall in the valley, screen the hole above the t chain or better yet, install a belt drive and use screens;



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Ain't Right Racin
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I pulled our custom made hundred holed pos out last year, it will never go back in. Oil psi went up by 30 psi on the big end.
 

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Official Test Driver
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Discussion Starter #6
It's crazy how much it reduces the ability for pan windage to meet upper engine windage to escape. The cam spinning, oil slinging does not leave a clear path. We actually make more power on a wet sump using oversize turbo drain bungs as equalizer lines to the heads! Fun stuff!👍


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It's crazy how much it reduces the ability for pan windage to meet upper engine windage to escape. The cam spinning, oil slinging does not leave a clear path. We actually make more power on a wet sump using oversize turbo drain bungs as equalizer lines to the heads! Fun stuff!👍


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Heard of power gains from vacuum pumps pulling from the pan or the fuel pump boss as opposed to the valve covers also. Then instead of the blowby fighting the downward flow, the source of the depression is assisting it.



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Official Test Driver
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Discussion Starter #8
👍vaccum/dry sump always makes more power due to this! O, and you don't need gobs of silicon to seal em up! Lol


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On another note, A screen would keep a lash cap or pushrod out from between the timing chain and gears i have seen a total meltdown on a missing lash cap.
 

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steelcomp was here
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Heard of power gains from vacuum pumps pulling from the pan or the fuel pump boss as opposed to the valve covers also. Then instead of the blowby fighting the downward flow, the source of the depression is assisting it.
Putting the vac. down in the crankcase and behind the pistons is a great idea; unfortunately no one I know has found a way to do it without sucking a ton of oil.
 

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Putting the vac. down in the crankcase and behind the pistons is a great idea; unfortunately no one I know has found a way to do it without sucking a ton of oil.

Lack of a better example, but, what about sucking it through a dry sump tank ? Could there be a small line from the bottom of the tank to the engine to allow the oil to drain back into the engine ?
 

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why not just use a 5 or 6 stage dry sump pump, and forget the vacuum pump and be done with it. After i went to a 6 stage dry sump pump on my twin turbo engine, i wouldnt use a wet sump system if someone gave me a brand new one.
 

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steelcomp was here
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Lack of a better example, but, what about sucking it through a dry sump tank ? Could there be a small line from the bottom of the tank to the engine to allow the oil to drain back into the engine ?
Depends on what side of the pump it's on. If it's between the engine and pump it has to be sealed and not sure how that would work. If it's on the exhaust side of the pump it can just go into the breather but I'm not sure about sucking that much oil through the vac pump.
 

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steelcomp was here
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why not just use a 5 or 6 stage dry sump pump, and forget the vacuum pump and be done with it. After i went to a 6 stage dry sump pump on my twin turbo engine, i wouldnt use a wet sump system if someone gave me a brand new one.
Cost and simplicity. Bottom line is, taking vacuum out of the top of the engine works fine if it's done right.
 

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Hey Steel, working on getting a 540 twin turbo done for my other boat with my new 29 lb each bullseye b480 lightweight turbos with the polished stainless v band exhaust turbine housings. Havent decided on which intake yet but leaning towards the dart tunnel ram which i have sitting on it dummied up right now.
 

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steelcomp was here
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Hey Steel, working on getting a 540 twin turbo done for my other boat with my new 29 lb each bullseye b480 lightweight turbos with the polished stainless v band exhaust turbine housings. Havent decided on which intake yet but leaning towards the dart tunnel ram which i have sitting on it dummied up right now.
That'll be impressive! :))THumbsUp
 

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Depends on what side of the pump it's on. If it's between the engine and pump it has to be sealed and not sure how that would work. If it's on the exhaust side of the pump it can just go into the breather but I'm not sure about sucking that much oil through the vac pump.
If its a dry sump its best to just use a pump that is meant to be a vac pump, may even have a stage dedicated to just that. The best way with a wet sump is the best baffling you can produce and a LARGE air separator that drains back to the pan. Star makes a pretty effective separator.

But you are right, you can't just stick some simple fitting in the pan like you can in a valve cover, and it does do the job pretty well.



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Or Seth, either one
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That's a great visual. I'll never look at valley screens the same again.

It also brings to mind some of the conversations around here about certain oil pick-up screens being too restrictive.

Thanks for the vid :))THumbsUp
 
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