MG, as you stated, the article was not written by engineers. It was written by 'Sleepy' from an interview. IOW, Sleepy's interpretation, and maybe he (Sleepy) was. I'll follow through when more time available.

 

In Opening statement

Like other parts in an engine, it can wear out, and it's inexpensive insurance to replace a stock pump.

[Comment #1: so far I agree]

Misleading:

Article omits to clarify there is an association between volume and pressure, in regards to what ends up going thru bearings. Also, written in a way as to put a product in one light (favorable),
and promote that product (hv pump). IOW, article suffers from a conflict of interest.

EXAMPLES:

In Opening Statement

The high-volume pump is designed to pump a higher volume of oil at the same pressure.

[Comment #2: to clarify; hv pump is designed to pump a higher volume, at a given equal specified pressure.]

....it may raise the oil pressure because a higher volume pumped into the same oil gallery space will cause a pressure increase.

[Comment #3: to continue sentence; IF... the volume requirement was higher than a given pump was supplying. IOW, if the volume pumped into gallery space was inadequate, in the first place. If adequate, pressure attained will be equal/limited to what pump was adjusted for.]

Under Heading: Stock Oil Flow

Usually, the bearing clearances are stock. Therefore, even to 7,000 rpm, a stock pump has sufficient volume and pressure to supply oil to the engine.

[Comment #4: This is important to note, cuz this includes 95% of forum members' engines. Know of many engines built with clearances not within the range specified in oem specs?]

Under Heading: High-Pressure Pumps

If this extra pressure is not needed, then the engine is using horsepower to pump oil to a peak pressure that is unnecessary--thus resulting in less power to the wheels. An additional loss is that windmilling the unneeded oil back into the pan aerates the oil and raises its temperature. A higher oil temperature can also affect the engine by raising the water temperature.

[Comment #5: This statement also applies to excessive volume as well.]

He said that although each engine might be different, the relief valve would probably start to open around the oil volume that could be used at 3,500 engine rpm. So, consider that too much oil pressure wastes horsepower.

[Comment #6: Having met the pressure requirement, means the volume requirement has been met as well. If volume requirementis not met, pressure would not build to that set by relief valve. See post from the 'dude', along my previous post.]

"The stock pump can take care of the bearings on most stock or near-stock engines. There are two good instances where a high-volume pump should be used. In a case where the bearing clearances have been opened up, allowing more oil to flow through, the higher-volume [pump] would be a benefit. This situation is not as prevalent now as in the past. Most engine builders seem to tighten up the bearing clearances now.

[Comment #7: See comment #4 under 'Stock Oil Flow'.]

"The other situation is when an oil cooler, or some other restriction, is added to the oil system. Then, additional flow is needed."

[Comment #8: "or other restriction"...Correct me if I am wrong here. Since when will volume correct a restriction? I am in the camp that reasons, a restriction calls for more pressure to overcome. Bearing clearances, a form of restriction, allow pressure to build. AFAIK, more volume is of little value in overcoming a restriction. Bearing clearances need to be increased, before more volume can be used effectively. Without supply changes (pressure or volume), increased clearances will cause pressure to drop.]

The high-volume pump can refill the accumulator faster while still having enough capacity to supply oil to the engine. In case you
haven't heard me say it before, I think an oil accumulator should always be used on a circle track race engine with a stock pan.

[Comment #9: Faster, yes. The oem sbc pump is capable of
delivering 9 gpm. How much time is needed to deplete/refill the
reservoir? Remember, it was stated, excessive pressure is not
required at high rpm. At what point, is the accumulator a band-aid, for a situation that calls for a system superior to 'stock', or
even a dry sump system?]

Under Heading: Use A Big-Block Pump?

Osterhaus and I had spoken before about the use of a big-block
Chevy oil pump on a small-block engine. My long-held opinion was that the big-block pump was costly overkill. I had thought it pumped too much oil, therefore heating up the oil, and was thus unnecessary on a stock-type engine.

[Comment #10: I don't recall a relevant rebuttal from either engineer!!]

Under Heading: Stock Conclusions

Use a high-volume pump when an oil cooler or an oil accumulator are plumbed into the oil system. High-pressure pumps can overwork the oil and cost power. The Chevy big-block pump may be a good alternative.

[Comment #11: First sentence; don't know 'bout you, but I'm not convinced. Second sentence; see comment #5 above. Third sentence; this article presented no evidence/proof to support such a claim. In fact, no relevant support info was even addressed.]

 

That dip/drop in pressure is a warning sign. Depending on how responsive your gauge is, it could conceivably be dropping lower than it is registering. You could very well be cavitating/sucking air. The question is why?

 

That was the first thing I checked - oil level. It's reading proper on
the stick.

Failing that, I tried a new oil filter. Same issue.

A little more history: My previous motor had what I believed to be
a stock oil pump and pressure regulation.

Hot values were 20 PSI @ ~900 RPM, and up to 60 PSI @ 6000 RPM.

I thought this was the norm and grew accustomed to it.

When I dropped in my new motor, I picked up a new pump and
it had the pink spring for high pressure operation. Not my liking,
hence the installation of the black spring.

I was told the black spring was stock regulation? I was also told
the white would give me stock regulation? Hmmmm...

Not sure what's going on. I don't believe it's a bad pump because
it threw out 60 PSI with a pink spring, and afterall it's "new".

Now I'm a little uncertain as to what I should keep. To be honest,
I think the drop in pressure is a little strange while rev'ing over
3500. I would expect the gauge to hold steady rather than drop
and climb again.

I've used the same oil grade/brand, same oil pan, etc. and never
experienced issues with cavitating, or sucking air.

Lastly, the bearings were plasti-gauge to 0.0015"

Photo link:
http://members.rogers.com/tdese739/plast.jpg

 

Arnie,
Don't know what the problem is about a HV pump.I can tell you that in my dirt track sprint car from the late '60's to early '70 we used the GM BB pump.My engine had .003 on the main's and .0025 on the rods.We ran Kendal GT-1 50W not for the clearances but when the radiator got packed up,water temp went over 300* and the oil was like water and you still had 15 laps to go(didn't know what syn. oil was)I ran the same block,crank,rod's and piston's for three years@5 nights a week in Penn.It wasn't robing us of enough power to worry about and the engine ran all season without a teardown.When I got time I would look at the plugs and lash.So to me the questions about a HV pump are a non factor.If you go screwing around with the relief spring you SURELY CAN have to much pressure and cut a nice groove all the way around the brg.(not good)If you want to experiment, put it in a bucket of oil and ger a BIG drill make a guage adaptor and see what it does.But those engineers pretty much know what it takes to get the job done.
The reason for the small clearances on todays engines is from the modern day THIN oil,and service LIMITS on an LT-1 are from .0007 to .0030 on the main's.So LIMITS are not any different than in the '60's

 

Just wanted to see you write all that Arnie.

I don't agree with everything written there either but I don't agree with alot of stuff out there these days.

Anti-cavitation features and blueprinting are more important to me than volume/pressure etc.. So I like to use pumps built with those things in mind in lieu of modifying stock pumps.

-Mindgame

 

After finished typing it, that is kinda what I felt like, too.