Testing High Volume Vs Standard Chevy Oil Pumps

Grumpy

The Grumpy Grease Monkey mechanical engineer.
Staff member
after reading all the posted info ,
you would more than likely avoid or skip the related links,
so I posted them at the beginning so you at least realize,
theres much more and useful info available
https://www.cpperformance.com/products/Engine_Parts/valve-spring-oiler.htm
btw if you don,t want to delve into the subject in any depth
the MOROSO OR MELLING clone of the Z28 SBC OIL pump in most applications works rather well in most SBC

https://www.jegs.com/i/Melling/689/M55A/10002/-1

https://www.jegs.com/i/Melling/689/55070/10002/-1?ymm=4294829802+4294829791+4294828856
moroso makes a decent performance oil pump
https://www.jegs.com/i/Moroso/710/22147/10002/-1



having a few accurate measuring tools helps

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Ive used several standard volume BBC oil pumps in SBC applications,
with very good success, but its critical you use and install the correct matching oil pump pick-up ,
that will maintain a 3/8"-1/2" minimum pick-up to oil pan floor clearance.

https://www.summitracing.com/parts/mel-10774
I must have heard the myth that a high volume or big block oil pump will suck your oil pan dry,
most people forget....oil flows in a repetative circle from the oil pan, through the bearings and oil passages that dump that oil right back in the oil pan where it recycles endlessly , you might get 2 quarts pushed up into the lifter gallery and heads at very high rpms, for a few seconds but if the drainage paths not blocked most of that oil in seconds flows back into the oil pan sump, especially if you have a decent windage screen/tray and if you have a well designed 7-8 quart baffled oil pan you will always have 5 quarts plus around the oil pump pick-up
an
oil pump is one component in a system,
all parts must match for the system to function correctly

every time Ive had this in the shop ,
Ive seen guys with a problem, guys install a high volume oil pump with no other changes and never bother to check clearances, the loss of oil pressure is the result of the pump not being able to easily and freely have oil flow into the oil pump pick-up due to the pick-up being about 1/8" off the oil pan floor, so you get good oil pressure at idle but by 3000 rpm, its starving for oil flow.
its the result of the oil pump pick-up being mounted closer than 3/8",
from the oil pan floor and use of a non-baffled 5 quart or less oil pan,

use a reasonable baffled 7-8 quart oil pan with a matched windage screen and its never been an issue


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pumping the pan drys, is a myth in a properly set up chevy,
hot oil drains from the upper engine faster than its pumped up there,
the highest volume of oil flow exits the bearings
,IN THE LOWER ENGINE AREAS
and in a properly set up engine its rapidly swept into the sump,
aided by a windage screen
here are many oil leakage points(100) in a standard Chevy engine.
16 lifter to push rod points
16 push rod to rocker arm points
32 lifter bores 16 x 2 ends
10 main bearing edges
9 cam bearing edges
16 rod bearing edges
2 distributor shaft leaks
1 distributor shaft to shim above the cam gear(some engines that have an oil pressure feed distributor shaft bearing

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http://garage.grumpysperformance.com/index.php?threads/sbc-oil-pump-noise.14582/#post-77554

http://garage.grumpysperformance.com/index.php?threads/bbc-oil-pump-in-a-sbc.2598/

http://garage.grumpysperformance.com/index.php?threads/whats-a-windage-tray-do.64/

http://garage.grumpysperformance.com/index.php?threads/oil-system-mods-that-help.2187/

http://garage.grumpysperformance.com/index.php?threads/installing-an-oil-pump-pick-up-tube.1800/


http://garage.grumpysperformance.com/index.php?threads/how-your-oil-pumps-pressure-bye-pass-circuit-works.3536/

http://garage.grumpysperformance.com/index.php?threads/basic-info-on-your-v8-lube-system.52/

http://garage.grumpysperformance.com/index.php?threads/testing-a-chevy-oil-pump.6479/


https://rehermorrison.com/product/oil-pumps/

http://garage.grumpysperformance.com/index.php?threads/bearings-and-oil-flow.150/

https://www.enginebuildermag.com/2015/02/understanding-todays-bearing-clearance-recipe/

https://www.enginebuildermag.com/2016/04/high-performance-engine-bearings/

https://www.enginebuildermag.com/2012/05/engine-bearings-and-crankshafts-best-friends-forever-bffs/

Small-Block Chevy Oil Pumps - The Great Oil Pump Test
Mix A Big Batch Of Pressure, Volume, Oil Viscosity, Temperature, And Engine Power And You Have The Makings For The Great Oil Pump Test


Jeff SmithwriterSteve Bruléphotographer
Sep 29, 2009


While everybody knows what the oil pump's job is and why it's there, few enthusiasts consider the lowly bubbler as a possible engine tuning resource. We've come to appreciate that it takes power to pump that oil, and as lubricants have improved over the last 10 years, we needed to know more about pressure, volume, and viscosity. Westech's Steve Brule proposed a flogging of four Milodon small-block Chevy oil pumps on a 372ci small-block Chevy. While somewhat mild, this small-block cranked out nearly 500 hp through two grueling dyno days of constant flogging with never a whimper. Even more impressive was the small-block's excellent consistency. If you're looking for a rock-solid small-block crate engine, the SHP is an excellent choice.


What we learned was that while there are not huge differences in terms of power, there are areas where small improvements can be realized with a careful approach to the combination of pressure, volume, and oil viscosity. Our tests showed us that big-volume, high-pressure pumps of years past may not be the hot ticket for all street engines. If after you read this story it suggests that 80- to 90-psi oil pressures that backyard engine builders used to brag about are now about as useful as last month's pine tree air freshener, then we've done our job.

Our Test MuleA small-block Chevy seemed the perfect engine for this oil flogging, so Westech assembled a great test engine that started out as a Dart Special High Performance (SHP) 372ci iron-block short-block assembly. Instead of using the typical 383 approach, Steve Brule at Westech selected a big-bore/shorter-stroke combo consisting of a 4.125-inch bore and a 3.48-inch stroke. The Dart SHP short-block came assembled with a set of flat-top hypereutectic pistons and a cast crank. On top of this, we added a set of Dart Pro 1, 200cc intake port aluminum heads and a Comp XR294 hydraulic roller camshaft. The baseline testing on this engine pushed the peak torque up to almost 450 lb-ft at 5,100 rpm and peak horsepower to around 477.

Oil Pump Test



Once Brule waded through all four pumps, the results followed a somewhat predictable path. Most surprising, however, was the performance of the stock pump. The plain Jane version not only high-fived the horsepower race but also (to no one's surprise) achieved the lowest pressure. The stock pump's pressure curve was also the opposite of the rest of the high-volume pumps. Given more time, it would have been interesting to modify this pump by adding a small washer to the pressure-relief spring, which may have improved the pressure curve slightly without compromising power. Another surprising result was that the big-block pump was not the big power loser we had predicted. The Rat pump did produce the highest average pressure but managed to require slightly less horsepower compared with the high-volume small-block pump.



It's also normal to see that as oil pressure increases, volume decreases. But in this case, the pump size changed. The variable between the stock, high-volume small-block and big-block pumps is we were testing increasingly larger pumps. It might also be suggested that the larger big-block pump with its greater number of gear teeth might create a more stable pressure curve that increases flow without having to work nearly as hard. This would minimize the temperature rise. The greater number of pump teeth would also help stabilize pressure. We also considered reducing the pressure on a big-block pump to see if that might improve its performance, and what would happen if we combined those changes with a less viscous oil like the 5W-20. As usual, it seems our test created almost as many questions as it answered. We didn't really expect to see major power differences, but it was surprising to see how well the big-block pump performed compared with its small-block brethren.

Click here for the oil pump test results chart


Oil Viscosity TestFor the second part of this lubrication lesson, we left the high-volume small-block pump in place and tried five different viscosities of oil just to see what would happen. Again, Lucas Oil supplied the slippery stuff, and the results were interesting even if they performed pretty much the way we expected. We retested the engine with a volume of 5 quarts of Lucas straight 30W petroleum-based oil to use as the standard followed by two street-oriented synthetics-20W-50 and 5W-20-and two exotic and very thin Pro Stock blends-0W-20 and 0W-10. After each test, the oil was drained from the pan and the filter. This meant a small amount of the previous test's oil remained in the filter, but we decided that it would have minimal effect on the test.


When looking strictly at power, we expected the heaviest 20W-50 weight oil to be the worst horsepower thief, so we were surprised when the straight 30W oil made the least power. This may be because it was also the only nonsynthetic tested. The chart shows that while the peak horsepower numbers changed slightly, the differences were far more apparent when we averaged the horsepower across the entire rpm band from 3,100 to 6,500 rpm. If you look only at peak or average power, it's important to note that the synthetics are clearly better than a straight weight, even with a more viscous oil like 20W-50. Comparing the 30W with the 0W-20 in terms of average power, the difference is 3.6 hp per rpm point. While that may not sound like much, with a properly tuned drag race car, it might be measureable on the dragstrip. Also notice that even though the 0W-10 outperformed the 0W-20 at the peak by 2 hp, the average was virtually a tie. Lucas says these Pro Stock race oil blends are really designed for 9,000-rpm race engines that begin to load parts pretty hard at rpm levels that our test never came close to seeing. Based strictly on horsepower, it appears from this test that a 5W-20 synthetic might be the best compromise among power, oil flow, and pressure.

Note also how the relationship between oil flow and oil pressure remained consistent in that as pressure increased, flow decreased or as flow increased, pressure decreased. As an example, the average pressure dropped more than 11 psi between the 30W and the 0W-10, while the average flow increased from 6.1 to 7.4 gallons per minute. That's a 21 percent increase in volume between the lightweight oils and the straight 30W. In fact, all three of the lightest oils flowed dramatically more than the straight 30W. It bears emphasizing that oil flow (while more difficult to measure) is actually more important than pressure in terms of engine life. Oil flow with some pressure behind it is far superior to low oil volume with lots of pressure behind it. Perhaps the biggest surprise was that the 20W-50 synthetic performed as well as it did against the lighter oils. The biggest differential compared with the 0W-20 is in flow, where the 20W-50 lost almost 14 percent. This is understandable when accounting for oil pressure, since the 20W-50 produced the highest average at 67.4 psi compared with 0W-20's much lower 59.7. That's well over a 10 percent difference. If an average oil pressure of roughly 60 psi doesn't bother you (and it shouldn't for a small-block Chevy), then it appears the 5W-20 would be a good overall choice offering excellent flow and the very good average power with acceptable temperature.

Click here for the oil viscosity test results chart

In this comparison, you can see the major difference between a high-volume small-block pump gear (left) and the Rat motor gear (right). The Rat motor pump enjoys a larger diameter and more pump teeth that should create a more stable output curve.

By the time Brule attacked the fourth pump, he had the swap down to about 20 minutes. We also maintained the exact same volume of oil for each test to ensure an accurate test.


https://www.onallcylinders.com/2016...can-use-big-block-oil-pump-small-block-chevy/

Ask Away! with Jeff Smith: Can I Use a Big Block Oil Pump on a Small Block Chevy?
Posted by Jeff Smith on October 28, 2016 at 9:43 am
A friend of mine suggested using a big-block oil pump on my small-block Chevy in order to get smoother flow and more volume with a stock volume pump? Will that work?

D.B.

Jeff Smith:
It seems there’s quite a bit of confusion regarding oil pumps and oil pressure so let’s focus on what’s happening. We’ve covered a part of this question before, so we won’t go into all the details again, but it is possible to use a big block Chevy oil pump on a small block. Several years ago, Steve Brule’ and I performed an oil pump pressure and oil viscosity test on a small block Chevy using Westech Performance’s dyno. The last pump we tried was a standard-volume big block Chevy oil pump compared to a high volume/high pressure small block oil pump. The reason you would want to use the big block pump is for additional volume as the Rat pump’s body is deeper than a stock small block pump and the pickup tube is larger in diameter.

What we found was the big block pump appeared to enjoy a slight advantage in terms of power over a small block high-volume/high pressure pump. Comparing the big block pump to the small block, the biggest change besides larger gears was the big block uses a greater number of teeth on the spur gears used to create the pressure. We think that the small advantage might be attributable to the greater number of teeth on the spur gears creating a more even flow (reduced pressure fluctuations) compared to the small block’s courser tooth pattern. We have no way of supporting this theory.

There are other issues that may affect this decision. First of all, because the pump is deeper, the pickup you choose may or may not fit the oil pan properly. It’s critical that the oil pump pickup be located roughly ¼ to 3/8-inch above the floor of the oil pan in order to not suffer from cavitation issues with low oil levels during hard acceleration. The oil pump will also have to fit between windage trays, pan baffles, and other obstructions that may require custom work in order to facilitate the use of this big block pump.

So the answer is yes, you can use a big block pump, but only if you can mount it with the proper position of the oil pickup. If the pickup tube cannot be properly located, then you have just lost any advantage you might have over a small block pump.

It’s also worth mentioning that the ability to create more oil pressure is not a good reason to use a big block pump. High oil pressure – above 60 psi for example – is not something to strive to achieve. There are plenty of examples of engines using high-pressure/high-volume oil pumps that produce much more pressure than is necessary. The old rule of thumb was 10 psi for every 1,000 rpm of engine speed. That isn’t a bad plan but frankly it is on the high side.

For street engines, oil pressure at idle are near ideal at 20-25 psi and maximum pressure at peak rpm can be 50 to 60 psi, assuming a maximum engine speed of less than 7,000 rpm. Hopefully, this information will help you with a decision as to whether you really need a big-block pump for a mild street engine. Keep in mind that oil viscosity also plays a part in how much pressure is created, especially when the engine is cold. It’s important to not put too much load on the oil pump drive shaft and gear with thick oil when the engine is cold as this can create excessive wear on the entire system.
that generally means you should allow the engine oil to warm up for 5-8 minutes under low loads and at idle before you consider putting much strain, RPMs , on the engine bearings/ loads etc. especially at temps under 60F
http://www.superchevy.com/how-to/148-0506-lubrication-systems/

Pumped Up
Lubrication Systems
Bob Mehlhoff Apr 9, 2005
Share
At 3,000 rpm, the pistons inside your engine are moving up and down violently, the crankshaft is spinning swiftly, and the rocker arms are rapidly doing the two-step with each respective valve. But whether your engine is just idling in drive or at full-throttle, it takes a good lubrication system to keep everything from turning into molten metal. To prevent this unsavory transformation, oil is directed to all of the metal contacting surfaces by a full-pressure lubrication system comprised of an oil pan, an oil pump, several quarts of oil, and a series of passages inside your engine. To learn more about how this stuff works, this month's segment is devoted to the lubrication system of a typical Chevy V-8.

A stock Chevrolet V-8 engine uses a wet-sump system (oil reservoir located directly below the crankshaft) with internal passages within the cylinder block, crankshaft, and openings in the cylinder heads. A 1/2-inch diameter oil pump inlet on small-blocks (5/8-inch diameter on big-blocks) with an ample suction screen submerged in engine oil provides free-flowing oil to the pump, which is driven by the camshaft. The oil that is supplied to the pump travels through a full-flow oil filter into a 1/2-inch main gallery on a small-block (9/16-inch on a big-block) that is located above the camshaft. From there, the lube travels through a hole to a groove near the rear side of the rear cam bearing ('57-and-later V-8s) and is where the lifters and rear main are oiled. Additionally, all four front cam bearings have grooves that pass to each particular main bearing. Through small holes in the upper main bearings, oil passes down into the crankshafts main journals where it travels to the rod journals.






While all of this is occurring, the crankshaft is spinning and each connecting rod is throwing oil onto the respective cylinders to lube the moving pistons and rings and help seal combustion. At the top of the engine, oil has traveled from each lifter and up through the hollow pushrods, over the rocker arms, and down onto the springs and valve stems where it helps to lube the valve stems as they move in the valve guides. To keep the pressure from getting too high at the oil pump, a relief valve circulates the oil back to the inlet side of the pump when pressure surpasses the relief spring's limit.


High-performance engines place increased bearing loads on the oiling system (especially during higher rpm), and if it's not up to the task, it can cause very premature engine failure. To combat this, most aftermarket high-performance pumps provide a 20-30 percent increase in both volume and pressure. For most applications, you'll want a good pump that delivers in the neighborhood of 55-65 psi or about 10 psi per every 1,000 rpm; anything more may just add air into the system or labor the engine with the task of turning an oil pump that makes excessive pressure. If you doubt that an oil pump takes power to turn, watch what happens to a drill motor during the initial phase of oil pump priming.

Most aftermarket pumps come with a new pickup installed and brazed into position. If yours does not, you should braze the pickup into the pump body, positioned about 1/4-inch (0.250-inch) above the bottom of the pan. Before brazing it to the pump cover, remove the pin, spring, and relief piston from the cover so that the heat won't damage them. Put the pump securely in a soft-jawed vise and tap the pickup into the oil pump with a homemade tool or one from a specialty tool company. To measure the pickup-to- pan clearance, place a small piece of clay between the pickup and bottom of the pan and install the oil pan gasket in a mock-up (without adding sealant).
But before you install a new oil pump onto the engine, it's always a good idea to double-check the end clearance of the pump gears beforehand. For most small- and big-block Chevys, the pump gear's end clearance should be very close to 0.0025-inch, but it's always best to first check with the pump manufacturer for the spec. To check this dimension, disassemble the pump and de-burr both gears with a small file. Then, reinstall both gears and measure the endplay (from the top of the gears to the top of the pump housing) using a depth micrometer or a feeler gauge. If you install a pump with a measurement that exceeds the 0.0025-inch spec, then the pump will not prime as easily and/or perform as well. If the endplay is greater than this, it can be corrected by sanding the pump body with a piece of solvent-wet 220 wet/dry sandpaper placed on a hard and very flat surface, such as a thick piece of glass. To correct clearance that measures too small, sand the gears on the top end in the same manner as the pump body. In either case, remember to wash everything in solvent and then blow-dry it (rags will leave lint) before reassembly.

To install the pump on the rear main cap, first be certain that the hole in the pump aligns with the hole in the main cap. This may require chamfering the holes so that they line up with each other.

Supply and Demand
Look inside of a stock or high-performance pan and you'll see baffles there to keep the oil pickup submerged during cornering, accelerating, or stopping. For high-performance pans, the baffling is typically far more elaborate and designed to better withstand the forces of extreme-duty operation. Critical to a good oil pan's design is also how well it allows gravity drain-back into the sump.

For many high-performance applications, the size of the sump may be larger than stock. For most street-driven cars, chassis and ground clearance requirements dictate the depth (and width) of the oil pan's sump area, so for many applications, wide sump pans are available.

At engine speeds above 6,000 rpm, the moving oil can whip the crankshaft and cost power. This phenomenon is called windage and is minimized by installing either a windage tray or a semi-circular screen to move the oil away from the spinning crankshaft without splashing back on the throws.

ConclusionBuilding the best oiling system for your engine depends on planning, budgeting, and how you'll use your vehicle. If you're simply building for moderate street and limited track use, there are many high-performance oil pumps and oil pans that will increase volume and pressure without destroying your budget. For very high-performance use, there are a multitude of oil pans, pumps, windage trays, and hardware to almost eliminate the possibility of encountering an oiling problem. The key is choosing the right parts, installing them correctly, and operating the engine the way it was designed. CHP
This Moroso high-performance oil pump has many features designed to provide a consistent flow of oil to the engine. The special anti-cavitation slots prevent the formation of oil foaming. The unique feeder grooves, enlarged bypass area, as well as the anti-cavitation slots, work to bleed oil back to the inlet side of the pump. This all adds up to a pump that provides a smooth and consistent oil flow and places an even load on the distributor shaft to help eliminate spark scatter at high rpm.

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From the oil pump, oil travels through the filter and into the block. After the initial 20 to 30 minute run-in of a new engine and camshaft, it's a good idea to drain the oil (with the engine still warm) and install new oil and a new oil filter. Neophyte engines produce a lot of small and sometimes microscopic debris. The adapter and spin-on filter, which began appearing on '68-and-later Chevy V-8s, is available from your GM dealer or Mr. Gasket. The Mr. Gasket adapter sells for about $18 (PN 1272).

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A cutaway shot of a new GM Vortec engine shows an oil filter from the inside out, as well as the internal path that the engine lube travels to and from the filter from the oil pan. This is called a wet-sump system because it carries the oil in a pan directly below the crankshaft and is what 99.99 percent of all modern production cars use. As a side note, some dedicated race engines (and the new '06 Corvette LS7/Z06 427) use a dry-sump system where oil is stored in a remote tank.

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This new Moroso CNC Billet racing oil pump (PN 22163) (a) provides closer internal tolerances to ensure very precise performance and pressure. Notice how large the inlet area is compared to the street style pump (b).

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The oil pump gears add more flow...

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...require a taller oil pump housing (arrows).

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The stock oil pump shaft may work fine for a production-type low-pressure pump, but if you're adding a pump with higher pressure, replace the original shaft with a quality steel shaft (left) to withstand the added pressure (available from Milodon and Moroso).

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The pickup provides the inlet for oil into the pump, and should be set 0.250-inch above the bottom of the pan (measured with a test gasket in place). Use a small piece of hobby shop clay to measure yours. The pickup shown (above) features a strap to secure it to the pump.

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This small-block is fitted with a windage screen and an aftermarket pickup designed to fit a special oil pan. At high rpm, a windage tray will provide extra horsepower because it keeps the crank throws from hitting the lube.

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Special studs, like these from ARP, mount the windage tray into position.

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The stamped steel screen on the bottom of the pickup prevents large debris from entering the pump and inhibits oil from leaving the inlet tube.

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At high-rpm, about three quarts of oil are on top of the engine (out of the pan), and there is always close to a quart in the filter, leaving one more quart in the pan in a typical five-quart system (right). A vehicle used for high-performance (high-rpm operation) driving should have a larger oil pan. For most drag-racing use, a deep sump pan works well because it adds capacity without increasing the area around the bottom of the pan as a wide-sump pan will (left); the wide sump spreads the area out around the pickup and more oil is required to keep the pickup submerged. Granted, for many street and road race applications a wide sump pan is the best high-performance choice because of ground clearance and steering linkage issues.

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If you need an oil pan for a unique installation, Dooley Enterprises custom makes some high-performance pans to order. Although largely for marine use, they also offer pans like this one for a '66 Chevy II that is receiving a GM Ram Jet 350 crate motor.

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New GM oil pans, such as this one used on the production Vortec 2800 I4, are cast from aluminum and feature special walls to contain and drain-back the oil. Cast-aluminum pans are also more rigid, especially along the gasket surface and are not as prone to leaking.

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This close-up shot of a pickup installed in the pump cover shows what a brazed-in pickup tube should look like. Just remember to remove the relief spring before heating up the pump for welding or the spring may weaken causing lower oil pressure.


https://stellartechnical.com/products/sil-fos-15-brazing-rods?variant=5368214126619&utm_medium=cpc&utm_source=google&utm_campaign=Google Shopping&gclid=Cj0KCQjwp4j6BRCRARIsAGq4yMHcjgBKY6oe0p7-knvvNsXU2lpl33Pi1KGgn6RxyRb5n4t4lgGI7hEaAqrKEALw_wcB
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This high-performance pump has a nice wide opening, which allows oil to travel freely through the rear main cap. If the cap does not have an accompanying hole to match, some chamfering may be needed.

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While reading several books on building performance engines I found one recurring message – stick with the stock big block oil pump! Apparently these pumps have a solid reputation for being bulletproof. Here’s what the stock oil pump looked like after a thorough cleaning.

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Oftentimes people replace the stock oil pump with a high flow or high pressure aftermarket pump as a matter of course when completing an engine build. However, much of my research seriously questioned this practice and made a compelling case in the process. First, for street and street performance use the stock oil pump is perfectly capable of pushing more than enough of oil (provided the correct main bearings are used and that bearing clearances are not ridiculously large). Secondly, high pressure and high volume pumps certainly do push a lot of oil, but much of that oil is simply forced out of the pressure release valve and never makes it through the engine. Also, don’t forget that pushing all that extra oil takes more work and more horsepower. Lastly, although a high volume pump could easily have been provided by GM engineers, they didn’t feel it was necessary – even on the high performance L-88 and ZL-1 models. With that in mind I started checking my stock pump to see how it looked, overall it was in very good condition. Below is a photo of the pump with the cover removed.




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Disassembly of the pump is quite simple, the parts are all slip fit so they’re easily removed. Prior to removing the drive and idler gears I marked their relative position so that they could be reinstalled in the same orientation.




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Despite the bullet-proof reputation of the stock big block oil pump several of my references recommended a few minor modifications when using them in a performance application. After giving this some consideration I opted to go ahead and make the modifications as they were explained and outlined in the book “How to Hotrod Big-Block Chevys”. The book is a good reference, although it’s a bit dated, but it provides some good info nonetheless. Considering used copies can be had for less than $10 it’s certainly a worthwhile investment.




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First on the list of modifications was to lightly chamfer the edges of the gear teeth with a file.




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Next, and perhaps the scariest modification, was pressure balancing the oil pump. By creating small grooves in the pump housing the hydrostatic forces on the idler and drive gears can be more evenly distributed. This reduces the amount of pulsating forces that are transmitted up the oil pump drive shaft and ultimately into the distributor. Although not a major problem, this pulsating has been known to contribute to spark scatter (changes in timing) at high RPM. The pressure balancing also helps prevent cavitation and allows the pump to operate more efficiently and on less horsepower. GM engineers provided some of these pressure balancing grooves on their high performance pumps (used on L-88 Corvettes), but these modifications go a step further. Having said that, below I’ve laid out the locations of the pressure balancing grooves on the pump housing.




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To make the grooves I used a Dremel tool with a bit intended for chain saw blade sharpening. The size of the bit (5/32″ diameter) was just about the perfect size and it worked very well.




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After a few hours of careful work the grooves were complete. Below is a picture of the modified housing. Note that care needs to be taken to assure the grooves in the cover (#1 & #2) need to line up with the vertical grooves on the pump housing (#1 & #2). The other two red arrows are meant to point out vertical grooves in the pump housing (a bit hard to see in the photo).




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Lastly, and probably most importantly, the proper end clearance between the gears and pump housing cover needs to be established. Excessive clearance results in poor priming ability and inefficient pump operation. Ideally end clearance should be about 0.0025 inches. If excessive clearance is found the housing can be sanded down by using a piece of fine to medium grit sandpaper placed on a flat, hard surface. Be sure to apply even pressure and rotate the pump often during this process to ensure material is removed evenly. Conversely, if the clearance is too small the gear height can be reduced by using the same sanding procedure above.




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After establishing the proper clearance and a very, very thorough cleaning I reinstalled the pump cover and screws using Loctite on the screw threads. That’s all for this update!
 
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So--how much oil pressure does any engine need to keep it lubricated? I have always liked lower pressure for you have less leaks from the gaskets and seals. Larger oil pan for capacity in case the oil is everywhere in the engine but not in the pan. I try to get to 45 psi at WOT and whatever is at idle will be enough--usually 20 psi, never thought any more would be needed. This is for street/strip engines--not elephant engines.
Have seen 95-105 oil pressure that blew the oil filters gaskets or filters blow out the sides.
 
the answer depends on both the engine design and clearances,
but from what I've read and seen through testing personally, given the correct clearances, pressure over 65 psi at W.O.T.
or over 20PSI at idle for a sbc or BBC adds no benefit.
some ford engines are designed to work with up to 100 psi of oil pressure at peak rpms
added oil flow rate volume helps cool and lubricate to a greater extent than added pressure

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yeah the linked info holds a great deal more info
http://garage.grumpysperformance.com/index.php?threads/testing-a-chevy-oil-pump.6479/#post-87726

http://garage.grumpysperformance.com/index.php?threads/oil-system-mods-that-help.2187/

http://garage.grumpysperformance.co...l-pumps-pressure-bye-pass-circuit-works.3536/


http://garage.grumpysperformance.com/index.php?threads/installing-an-oil-pump-pick-up-tube.1800/

http://garage.grumpysperformance.com/index.php?threads/bearings-and-oil-flow.150/

http://garage.grumpysperformance.com/index.php?threads/shimming-an-oil-pump-relief-spring.16240/

http://garage.grumpysperformance.co...elling-shark-tooth-oil-pump.12381/#post-78015

http://garage.grumpysperformance.com/index.php?threads/basic-info-on-your-v8-lube-system.52/
 
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watch the videos, and always disassembly and inspect any oil pump,
clean and inspect your oil pump internally and at least use loc-tite thread locker

or ideally use safety wire on the bolts and BRAZE the oil pump pick-up to the pump body.
 
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