[Steve C.]

CNC machined Oil Slot ?

For interest, Precision oil pump cover plate....

http://stores.precisionoilpumps.com/...p-cover-plate/

Stock Melling pictured here....

https://www.pontiacdiy.com/wp-content/uploads/78.jpg

"Melling produces two stock replacement Pontiac oil pumps. Each is available in 50- or 70-psi variants, which generally produces 60 and 80 psi, respectively, with normal production bearing tolerances. The standard pump (left) is built to exact OE specifications. The Select Performance pump (right) features tightened tolerances and billet gears to improve performance and reliability, particularly at high engine speed."

Butler oil pump....

https://www.pontiacdiy.com/wp-content/uploads/98.jpg

It begins life as a standard Melling unit that Butler blueprints and adds a thick bottom plate to maximize performance.



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[slowbird]

Originally Posted by Tom Vaught

Just because someone does something to a part to make it unique and possible sell better is a marketing tool for the unknowing.

I think this about sums up this thread.

[Tom Vaught]

In the case of the Luhn Modified oil pumps, his mods are based on real world testing, a oil pump dyno, and of course the previous knowledge obtained from a Research Engineer who did the job for a living and worked with Aston Martin to design proper oiling systems when Aston Martin was a part of the Company she still works for as a Research Engineer.
Aston Martin has used the larger Inlet Tube Diameter on all of their engines in the past FOR A REASON.

I personally have two of his modded Oil Pumps. Modded pumps by others and how well they work or do not work is their concern.

Tom V.

[BGus16]

Been a while since i last did gear pump cavitation testing on aviation main engine fuel pumps. 7500 shaft HP unit for a GE helicopter engine.

But i can relate that we would needle valve the inlet supply line to the pump so we could snub down the inlet to force it into cavitation. This pump would go into cavitation around 6 PSIA. We would data capture all parameters. Flow and pressure would of course drop and you can hear it with your ear when it starts.

As a side note about the circular cuts in the bottom plate, that is a leak path that will reduce pump output for sure. Also keep in mind that the gear tooth chamfers are very important to pump longevity and flow output. Too sharp and you will get more flow but tear up your end plate. Too large of a chamfer say from deburring and it can really reduce the flow.

Also keep in mind that when your reduce your pump flow output if effects you at idle also. Output is almost liner per RPM depending on leakage or back pressure. I often see it referred to as CIR. Cubic inches per revolution.

I can tell you that cavitation is somewhat of an art along with all of the engineering. Sometimes it can be hard to understand hows and whys of it.

[slowbird]

Im confused, the Nitemare base plate is wrong due to the machined circles in them for the gears?
But this pic is of a base plate from Luhn, is it not wrong also then???

[grivera]

Originally Posted by slowbird

I think this about sums up this thread.

What's disturbing is the grooves resulting in reduced oil flow going to the engine - so actually worse than the factory style plate.

Would this result in lower oil pressure at the gauge?

[Steve C.]

Of interest. Not Pontiac specific but here they mention cavitation....

"While most applications – whether stock or performance – use a wet sump system, it should be noted that they have some rpm limitations. There is a physical limit related to rpm on a wet sump, where once that threshold has been crossed, the gears or rotor sets can no longer continue filling with oil, and cavitation will begin. This happens typically somewhere between 6,500 and 7,500 rpm, but may occur at lower or higher rpm levels."

https://www.enginebuildermag.com/202...umps-and-pans/


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[Steve C.]

The Luhn Engineering.....

"Machined O-ring seal on the block mating surface at the oil pump body mounting pad"


"This feature is our Low Drag gear set option which is enhanced by our proprietary designed oil circuit built into the heavy duty thrust plate. The modification allows the gear set to "float" on a channel of oil thus reducing the coefficient of friction between the mating surfaces."

http://www.luhnperformance.com/image...ldg_option.png


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[PontiacJim1959]

May have missed it, but what good is a high flow GPM pump if the oil filter media doesn't flow anywhere near what the pump can? ie, 20 GPM pump and 9 GPM oil filter. Is the filter bypass taking up the difference?

May have missed this too. The higher GPM pump may flow more, but what good is that if the oil passage in the block from the pump to the filter does not reciprocate the higher flow of the pump? I have seen in some articles where the oil passage is opened up to a larger diameter to allow for the higher GPM flow of the pump. If the oil passage from the pump mount to the filter is not opened up and then honed to a smooth finish, what kind of increase would be actually seen by the higher pump GPM?

From the same engine builders article, does this relate in the discussion?:

"Schumann notes that the paddle wheel (designed oil pump) is good for about 8-10 hp out of the gate on a crate engine, for example, with more oil instantly. “Where the paddle wheel shines is not at idle, although it helps idle pressure out of idle volume when you take it to drag strip, and the third yellow light comes on, and your foot goes to the floor. You’re just worried about reaction time at that point. With a stock pump or stock valving style pump, it’s designed to do the following: As soon as the oil pressure comes roughly up enough to bypass the internals, where does oil go? As good engine builders know, you have cut off all the oil leaks, and you do not fill the valve covers up anymore. But the oil has to go someplace – the path of least resistance is back down the intake tube.

“So now you’re launching your car on a green light, and your oil pressure is going backward – doesn’t sound too good to me. Our 140 patented process eliminates the reversion of oil going back down the intake tube. It can’t do it, it’s impossible. The reaction time is fantastic with the paddle wheel. No more two, three, or four-second delay where the engine outruns the pump. It keeps up very well.”

[Tom Vaught]

Originally Posted by Steve C.

The Luhn Engineering.....

"Machined O-ring seal on the block mating surface at the oil pump body mounting pad"


"This feature is our Low Drag gear set option which is enhanced by our proprietary designed oil circuit built into the heavy duty thrust plate. The modification allows the gear set to "float" on a channel of oil thus reducing the coefficient of friction between the mating surfaces."

http://www.luhnperformance.com/image...ldg_option.png


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The Luhn oil pump gears with the machined dimples does a couple of things.
1) The oil is trapped in each dimple. The dimples do not bleed back oil from the high pressure side to the low pressure side like the machined "Race Track" does.

2) The Luhn Dimples actually trap more of a Oil Film between the gears and the Pump cover.

A interesting thing I noticed on one of the pictures (attached) shows a oil pump with the pump gear shafts supported on both ends of the shafts.
See the machined pockets in the cover for the oil pump shafts. NO SHAFT DEFLECTION THERE. I might have to talk to Mark about that feature in some of his oil pumps with the 19 gallon capability. Look closely at the machined "pockets for the shafts in the cover.

Tom V.

[Steve C.]

Posted for interest only. Googled up material so take it with a grain of salt....

"These claims of X GPM of flow by the manufacturer doesn't qualify the spec. For it to make sense they need to say X GPM at Y PSI delta-p with Z oil viscosity. Keep in mind that oil filters are typically 1/15 the flow resistance of the engine. The only time a more resistive filter effects flow to the engine is when the oil pump hits pressure relief. A more restrictive filter can cause the oil pump to hit pressure relief with less flow output compared to a less restrictive filter. But the filter would have to be very restrictive to make an oil pump hit pressure relief when the oil is fully hot and thin. One of a few good reasons not to go nuts with the throttle until the oil is at full temperature to ensure good flow to the engine."

https://bobistheoilguy.com/forums/th...ilters.276443/


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[grivera]

Tom- how about post 45? If this is a Lunh base plate then the Nightmare is good or both are not good? Is there a difference we’re not seeing?

http://forums.maxperformanceinc.com/...7&postcount=45

[steve25]

I have to ask a question here in terms of oil volume.

If I am not mistaken it was Grumpy who determined that a motors need for additional oil volume levels off at a certain rpm because you just can’t pass any more oil thru however many oil feed holes the motor has once there flowing 100% of what they can , or what they can flow with the given restrictions that are placed in front of them such as Bearing clearances and such.
Is this not the deal?

So for instance let’s say that even with the big mains of 3.250” that at 5000 rpm the motors need for oil volume tops off and that this level of oil volume can be met with the usage of the high volume 60 psi pump, even with increasing rpm well above 5000!

Here’s another question, what’s worse in terms of making a pump go into cavitation, more or less Teath on pump gears or not?
It would seem that with a Gyrotor type pump that less is better maybe?

[Dragncar]

Originally Posted by grivera

What's disturbing is the grooves resulting in reduced oil flow going to the engine - so actually worse than the factory style plate.

Would this result in lower oil pressure at the gauge?

I can not find any info on their site with a picture of their plate with the 2 circle groves.
They list the little dimples in their gears as a 60$ option.
I think the dimples with not groves would be the way to go.

[Tom Vaught]

Originally Posted by slowbird

Im confused, the Nitemare base plate is wrong due to the machined circles in them for the gears?
But this pic is of a base plate from Luhn, is it not wrong also then???

Show me on Luhn's website where he is doing that mod to his oil pump covers.
I see no picture like that. Would not be the first time photos were mis-labled on the web.

Tom V.

[slowbird]

Originally Posted by Tom Vaught

Show me on Luhn's website where he is doing that mod to his oil pump covers.
I see no picture like that. Would not be the first time photos were mis-labled on the web.

Tom V.

The pic wasn't taken from the internet, i took the pic, that plate was purchased directly from Luhn.

[Tom Vaught]

I have not talked to him in the last few months, but I saw no reference to that modification on his website. If he was easier to get a hold of I could ask him why he started doing that modification. Putting divots in the gear teeth may offer some benefits but the circular grooves ??? Is this a mod on his 19 gallon a minute pumps now.
When did you buy this cover?

Tom V.

[Tom Vaught]

I have a call into Luhn Performance to discuss the pump mods.
Very difficult at times to discuss things with him.

Tom V.

[AG]

I haven't seen any data to indicate the machined circles in the baseplate decrease oil flow.

[TedRamAirII]

Can we see a pic with a gear, sitting in the proper position on the base plate? if the groove doesn't meet the bottom of the teeth, it should not make any difference.