[Dragncar]

http://www.bmeltd.com/oilpumptest.htm

Bill Miller has a oil pump test video and it is about enlarging your pump pickup dia and what it does for your engine.
Now this test is on a dry sump system with 4 different pump. 2 are gearotor and do not pertain to Pontiacs. But he does test a gear pump with 1.8" tall gears. Our gears are 1.5" tall.
In the test he used a 1" AN intake dia and that pump started cavitation at 7500 RPM with a actual dia of .850 on that 1" line.
He then bored it out to .930 (15% increase) and did the test and the cavitation RPM went to 8300 RPM.
In the video he said at the end if anyone had any question to give him a call, so I did. I told him I was not dealing with a dry sump or a 500" Mopar and he asked what I am working with. Told him a wet sump Pontiac that would be done by 7500 RPM. I gave him the stock dia of our pickups as .609 with a 1.5" gear set.
What I wanted to know was with our small size suction side what would it do to the cavitation RPM. He said lower it. Than asked if me enlarging it to .818 like I have done would help the situation. He told me yes it would.
It would be nice to have a actual test on our pumps to find out at what point they start mixing air with our oil but have not seen that test.
But when take his information in you would have to conclude that any Pontiac with stock dia pickup has to have some air in the oil at high RPM. Does it mean they will blow up, nope.
But its not a good thing either.
Bill Miller is kind of unique. Just call up BME and he picked up the phone and is willing to give information. If I ran aluminum rods his are the ones I would buy.

[Stan Weiss]

Maybe John Langer will post up what he is running since I believe he turns over 9000 RPM.

Stan

[Dragncar]

He runs a Melling pump from a post years ago. But its not about this racer or that racer and what they do. I am positive a LOT of racers have been very fast without issues with the Melling pump.
In BMEs test they ran it up on a electric motor to 8K. Was it 1/2 simulated crank RPM for the 8K ? It looked like a 10-15 HP 3 phase motor. Changed a lot of those and never seen one that turned anywhere near that high.
What is the ratio on a dry sump pump vs engine speed ?
Atmospheric pressure is what pushes oil into the pump. So when you run a V pump and pull say 20" of vacuum how much does that decrease atmospheric pressure in your crankcase pushing oil into the pump ?
Sea level air pressure is about 30". So if you are pulling 20" is 10" of vacuum all that is pushing oil into your pump inlet ? On that alone increasing the size would be a good thing.
Let alone cavitation.

[Elarson]

Bill is an engineer, a manufacturer, a nitro crew chief and a car owner. He knows all aspects of what's happening like nobody else. He's been a trusted advisor to us for a lot of years.

Eric

[Elarson]

Boss Bird dry sump pump ran at 57% of engine speed with a -20 inlet.
42 gpm, 70 weight oil heated to 120 degF, 250 psi to the engine.

Eric

[mgarblik]

We had our single stage Petersen pump tested by BME on his test fixture. We were killing main bearings every single run on that engine in the early days. He felt our pump would be an underachiever and was not impressed initially. After all, it wasn't a state of the art hemi!. After it came off the test fixture, true to form, he admitted he was very impressed with the smoothness and output of that little belt driven pump. I have the graph of the test somewhere. If I can find it I will post it . May take some digging. BTW, the oil pump wasn't killing the bearings. It was insufficient main oil clearance and volume within the block structure. Opened up the main gallery, honed and chamferred all the openings, added a TON of main bearing clearance. .0065-.007" main bearing clearance, 70W nitro oil. Bearing problems went away completely.

Found the image:

[Dragncar]

One thing I learned watching his video was gearotor pumps go into cavitation at a much lower RPM than a gear pump. I always thought a gearotor pump would be a improvement if they made one for a Pontiac.
Luhns site had something about a Pontiac gearotor pump in the future.
Guess there is no need.

In BMEs test with 1.8" tall gears and .850 inlet. Our small .609 inlet would cavitate sooner but having shorter gears, 1.5" vs 1.8" would raise the cavitation RPM.
You would move less oil at a given RPM so it seems cavitation RPM would go up.
The only way to find out for sure is make a tester for a Melling style pump. I made a jig where you can hold your pump in a 5 gallon bucket half full of oil with one hand and a drill in the other with gauge attached.
But that is just for setting pressure before installation. Pulling your pan on and off gets messy.
Safely spinning that sucker up to 4000RPM would be a whole other deal. But it would be interesting finding cavitation points at different RPM with different size inlets. Checking commercially available pickups and where they start to have issues.

[johnta1]

Our small .609 inlet would cavitate sooner but having shorter gears, 1.5" vs 1.8" would raise the cavitation RPM.

The taller gear would require a bigger diameter inlet pipe to keep from cavitating. The 2 go hand in hand. (if you need more cfm, need bigger inlet and taller gear)

[Elarson]

Originally Posted by mgarblik

We had our single stage Petersen pump tested by BME on his test fixture. We were killing main bearings every single run on that engine in the early days. He felt our pump would be an underachiever and was not impressed initially. After all, it wasn't a state of the art hemi!. After it came off the test fixture, true to form, he admitted he was very impressed with the smoothness and output of that little belt driven pump. I have the graph of the test somewhere. If I can find it I will post it . May take some digging. BTW, the oil pump wasn't killing the bearings. It was insufficient main oil clearance and volume within the block structure. Opened up the main gallery, honed and chamferred all the openings, added a TON of main bearing clearance. .0065-.007" main bearing clearance, 70W nitro oil. Bearing problems went away completely.

Found the image:

The Peterson pump uses a twisted rotor design; which looks a lot like a roots blower. Bill's testing showed that it worked well and our on-track testing proved that it could move lots of bearing garbage thru the scavenge section without damage. I disassembled and cleaned it frequently and I was impressed how it kept coming back for more.

Eric

[Dragncar]

Originally Posted by johnta1

The taller gear would require a bigger diameter inlet pipe to keep from cavitating. The 2 go hand in hand. (if you need more cfm, need bigger inlet and taller gear)

I understand that John. Trying to estimate when our .609 inlet would have issues with 1.5" gear set. Pontiacs were never designed to turn 8500 RPM. Puny heads and all that. So the engineers designed a pump for intended RPM range.
Lots of money sitting on top of our Melling pumps.

[Tom Vaught]

My test car for Boosting Work would run to 8500 rpm every shift.
As Johnta1 posted, the Aston Martin engines were the first ones to use the LARGE
Inlet Tube Oil Pumps, based on work by the "Oil Pump lady". Jaguar followed as did the
American Engines. It does not take long for others to follow when a concept is proven to work.

If you are able to move more oil in the same time frame, then you can run larger clearances and
let the hot oil (and it gets hot quickly in the bearing area) be replaced by cooler oil.

The Oil Test Rig, Tom Tibbles designed, let us really document what was happening in the rod bearing area.

Tom V.

[Jack Gifford]

Originally Posted by Elarson

... The Peterson pump uses a twisted rotor design; which looks a lot like a roots blower...

I run a Dailey drysump pump on my landspeed hemi. The pump sections are all Roots-style, non-helical. I wonder if Bill Miller has tested a Dailey pump?

[Tom Vaught]

Jack, we have used a lot of the Aviad Dry Sump Pumps on, our test engines.
They were built the same way your dry sump pump was set up, except the Pressure Side used Gears.

Mostly 4 stage stuff, One pressure and 3 scavenge. A few 5 stage.

https://www.aviaid.com/

I still have a scavenge section on the shelf that used the straight vane Roots style
gears there. New Pump.

The Pressure stage still used the Large Gear tooth pump at the front of the assy.

https://aviaid.com/blade_templates/1142.pdf

Tom V.

[Stan Weiss]

Tom,
Is there any rule of thumb by looking at oil viscosity and pressure differential. How many GMP a square inch area of pickup tube will flow?

Stan

[Tom Vaught]

No idea, Stan, I never asked the Oil Pump Lady that question and she retired a couple of years ago I am told.

Tom V.