Oil pressure,oil volume question

I used a twin pickup system developed by Chrysler back in the day. It involved grinding a hole in the pump cover and brazing a pipe nipple on. Then a hose to another nipple welded into the bottom of the pan with an internal pickup. Twin pickups worked like drinking a milkshake with 2 straws instead of one. It was easy to do on the b block Chrysler because they had external pumps. Dont know how you would ever do that on a Chebby except to possibly increase the size of the pickup tube? I always ran the pressure low, 40 or so (40,000 miles on a 383 that I wound up to 7800 often). Two times I ran the 1/4 mile with no oil on purpose! Desperate times desperate measures.

 

Leo, never use a drill sir. You always use a 1/4" die grinder either air or electric. The die grinder is used to turn " rotary burrs " . They are usually made of H.S.S., and some are carbide. They come in both single cut, and double cut, and there are ones for ferrous and non-ferrous metals. The non-ferrous such as aluminum are very course burrs and you need to use a lubricant to keep the metal from " gumming " up the flutes. Ferrous metal burrs such as for steel or cast iron are much finer, and don't require any lubricant. You definately need to have variable speed control over your die grinder, be it air or electric powered. Serious injury can result from trying to drill with a large twist drill and drill motor into cast iron. TR

 

Does this occur from excessive pressure and or volume,or just a factor of fluid dynamics?

 

On another site I have posited that oil supply throughout an engine is not one even flow but actually pulses of oil. Especially with geared oil pumps. I have further offered that if there is an oil supply problem that is architecturally inherent to the block, as oil demand goes up, these oil pulses, combined with the built in block deficits can combine to cause bearing problems. Longer or larger gears will change the oil pump timing as will other types of pumps (gerotor, vane, etc.). I feel that is why dry sump oil systems work so well.
Also would someone address round, partially covered round, and rectangular or square pickups.

Thanks, John

 

Today's technology has added another factor into this controversy about hv vs stock pump.
Comp Cams now has solid lifters for many engines that have a hole .012" edm'd into the internal oil chamber from the lifter face, this aids in cam lobe oiling. So this adds 16 .012" bleed holes into the system. I have these lifters in the sbc in my roadster, having seen too many flat cam lobes lately.
Called Comp and talked to a tech rep before buying cam,lifters and springs, he agreed that an hv oil pump should be used.
So far so good on Joe Gibbs brakin oil oil pressure around 50 psi, going to Amsoil 10W-40 Prem protection high zinc oil when I change soon.

 

A "pressure balanced" pump helps w/ the pressure pulses. The pickup design is crucial
in consideration of cavitation. The perforated metal commonly used has only about 40% open area. Also with vane clearance only being a few thousands, you might question the consequences when the screen passes debris through holes 10 times the vane clearance. Dual pickups as mentioned can utilize somewhat tighter screens

 

Yup. And the same thing should be done throughout the system, at least where accessible. For instance, you can clean up the cap/pump mount interface on chevies. You are WAY better off getting volume by making an effort to make what is there operate more efficently, making sure the oil isnt where its not supposed to be, checking/correcting end plate clearance, adding anti-cavitation grooves to the pump body, cleaning up corners and flash in the galleries, ect.
Pressure/volume requirements of the engine itself are influenced by a shitload of factors, including bearing clearance and rod side clearance, journal diameter, stroke length, routing ect.
Cam makers dont like it, (excess oil up top helps control valve spring temps)but I lean towards doing EVERYTHING I can towards minimizing the engines pressure/volume requirements. Power gains from reducing pump size are minimal at best. The same is NOT true re: power gains from reduced windage, oil control, and the other things you can do/get away with as a result. The potential power gains are SUBSTANTIAL. And thats about as specific as I am going to get. The info is out there, if you really want to do your homework.

 

ANYTHING you can do to reduce restriction on the inlet side of the pump will pay dividends.

 

High volume oil pumps and big valve springs are great if you need them but just cost hp if you don't.

 

Is anybody using an accumulator to smooth out the pulses and cover any starvation? We used one in a circle track car back in the 70s in a class where dry sump systems weren't allowed.

 

In hydraulics, cavitation problems are pretty well eliminated by pressurizing the reservoir. Harder to do in an internal combustion engine.

 

Ttt

 

Another cool thing about a accumulator is with a solenoid valve in the system you can prelube the engine.

 

After reading all the replies,some good info here.And an HV pump is not needed...but I see no proof that the HV pump can empty the oil pan by over oiling the top end.

 

I have some hands on expereince with windage drag in an engine.

I drive a very OT VW diesel, only 52HP.
With the pan 1/2 quart over full or full, the car accelerates (if you can call it that) noticeable slower than when the pan is at the 1 quart low point.
I have always suspected oil drag on the crank as the culprit.
I do believe reducing windage with a crank scraper on any engine is time well spent.

 

It can do that but the perfect circumstances need to be present.
Modification to the oiling system to provide increased oil delivery to the top end without any modifications to the oil return capacity. Maybe a missed restriction / obstruction in the oil return.

 

Hi TR.Thanks for the info.
Good luck.Have fun.Be safe.
Leo

 

You are very welcome Leo, glad I could help, TR

 

Simple answer to the original post. If your stock pump and your HV pump both have 50PSI relief valves, and your engine gets to 50PSI at 3500 RPM with the stock pump, then it will get to 50PSI at a lower RPM with the HV pump, due to the higher volume. At the same RPM (your 3500 RPM Example), the high volume pump will simply be dumping more oil through the bypass and back into the pan.

 

yes. I use it as a back-up to allow me to minimize the oil level in the pan. In my experience, its worth power.

 

<TABLE dir=ltr border=1 cellSpacing=1 borderColor=#000000 cellPadding=2 width=564><TBODY><TR><TD height=19 width="35%">

Oil Pump Test Results​

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Oil Pump​

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Peak HP​

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Average HP​

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Average
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Average Flow
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Peak Temperature
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Standard volume (PN 18755)​

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485*​

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391.6*​

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50.3​

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6​

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160​

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High volume (PN 18750)​

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477​

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386.9​

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64.2​

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6.2​

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159​

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High vol., hi-press. (PN 18770)​

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481​

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389.7​

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65.6​

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6.1​

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160​

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Big-block (PN 18760)​

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480​

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387.5​

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68.0*​

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6.3*​

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161*​

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* Peaks​

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info from http://www.carcraft.com/techarticles/ccrp_0911_small_block_chevy_oil_pumps/viewall.html

pretty interesting stuff.

 

Ebbsspeed said what I was going to say about high volume increasing pressure at low rpm. We had a Versatile tractor with a 391 Ford engine and a HV pump so when it was throttled down it retained more pressure.