Excessive oil pressure

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Kevin Johnson
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Re: Excessive oil pressure

Post by Kevin Johnson »

MadBill wrote: Sat Sep 22, 2018 8:34 pm Smokey advocated the use of a BBC pump in an SBC for this reason.
Hey, he was pretty sharp, eh? :wink:
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Re: Excessive oil pressure

Post by Kevin Johnson »

Types_of_oil_pumps.gif
Pressure_fluctuations.gif
Power_demands.gif
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Re: Excessive oil pressure

Post by wilson1970 »

Gnicholson you posted about balance grooves, could tell us more? Would that make a difference in the pressure also. If I would remove the lump and put a lighter spring in should I make this modification?
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Re: Excessive oil pressure

Post by Roundybout »

When would a HV oil pump be required or recommended? Piston squirters? Oil spring cooling? I guess at that level you'd be drysumped.
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Re: balance grooves

Post by Kevin Johnson »

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Re: Excessive oil pressure

Post by gnicholson »

im talking about grooves machined or cut into the pump body and cover. the idea is to dampen pump pulses that cause spark scatter etc. it also creates internal leakage and lowers idle oil pressure some. this mod has been around a long time and moroso makes pumps that allready have this done. obviously you have to remove the pump to do this and if you do that you might as well just put the z28 pump in. im not sure what lump youre talking about. how much oil pressure does it have now hot at higher engine speed?
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Re: Excessive oil pressure

Post by MadBill »

Several interesting reveals in the data Kevin posted:
0 Huge difference in the pressure pulsation between a coarse tooth gear type and and a fine tooth crescent type. Wonder what a 12 tooth gear output would look like?
o Big difference the opposite way re power absorption, but all suck up far less than many people think/claim: At only 2 HP @ 6,000, no magic is going to give a significant reduction, especially if the curves are pump RPM vs. engine speed, e.g. crank-driven LS vs cam driven SBC.
:-k
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Re: Excessive oil pressure

Post by GuysMonteSS »

Melling also makes anti cav pumps for both the sb and bb.
Those ones have a C at the end of the part number.
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Re: Excessive oil pressure

Post by Monza Harry »

Melling also offers a pump with helical gears for smoother oil flow and drive loads [which was their target], looking at the twist in their video they didn't go far enough from my experience to make much difference. And to answer the repeated question " Why High Volume" pumps are used, they were built for "Loose" engines, [band-aid a worn engine, or for an engine built looking to reduce parasitic loses from a tight bottom end] and potentially other things like twin turbo's, bypass coolers and some of the other stated things from etc.. Harry P.S. Here is Melling's YT vid:https://www.youtube.com/watch?v=KGxt2i96QEs
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Re: Excessive oil pressure

Post by pdq67 »

I guess that I would have added some good old MMO on top of my oil and then checked my oil pressure before I would have went to too much trouble trying to lower it. Maybe up to a cup of MMO...

And back when I was a kid, I ran 10 wt in the winter and 30 or 40 wt in the summer, straight blend. He, He!! The bulk stuff in the quart canning jars with the metal pour spouts that set out front by the pumps...

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Re: Excessive oil pressure

Post by GRTfast »

pdq67 wrote: Sun Sep 23, 2018 9:56 am

...back when I was a kid, I ran 10 wt in the winter and 30 or 40 wt in the summer, straight blend.
I didn’t know horse carriages used oil... :wink:
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Re: Excessive oil pressure

Post by wilson1970 »

Ok hear goes. I changed oil from 15w40 to 10w30 Valvoline VR1 today. Cold idle is #65 after driving for 30 minutes idle at the stoplight down to #35-40 & 60 at cruise. Engine runs awsome.
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Re: Excessive oil pressure

Post by swampbuggy »

Wilson1970...an engine with average clearances will be just fine with 10-30 wt. Hard to beat with ambient temps between 50 to 100 degrees . My personal opinion. Mark H. :)
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Re: Excessive oil pressure

Post by CGT »

Kevin Johnson wrote: Sat Sep 22, 2018 12:48 pm
Ed Wright wrote: Sat Sep 22, 2018 11:56 am
gnicholson wrote: Thu Sep 20, 2018 6:44 pm you installed a hv pump and you dont understand why the pressure is to high with your stated bearing clearance?
Why would anybody put a high volume pump in a SBC??
Ask GM:

ZZ383_oil_pump.png

HV_oil_pump_PN93442037.png

https://www.chevrolet.com/content/dam/c ... 301295.pdf
https://www.summitracing.com/parts/nal-93442037
That is a standard volume pump with a 3/4" inlet pictured, and that is what GM used from about 96 on.
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Re: Excessive oil pressure

Post by Kevin Johnson »

CGT wrote: Mon Oct 01, 2018 9:43 am ...
That is a standard volume pump with a 3/4" inlet pictured, and that is what GM used from about 96 on.
The picture used was from Summit; here are a couple from Jegs:

https://www.jegs.com/i/Chevrolet-Perfor ... 7/10002/-1

versus

https://www.jegs.com/i/Melling/689/M155/10002/-1
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