Excessive oil pressure

General engine tech -- Drag Racing to Circle Track

Moderator: Team

User avatar
MadBill
Guru
Guru
Posts: 13593
Joined: Tue Nov 15, 2005 10:41 am
Location: The Great White North

Re: Excessive oil pressure

Post by MadBill » Sat Sep 22, 2018 8:34 pm

Smokey advocated the use of a BBC pump in an SBC for this reason.
Felix, qui potuit rerum cognscere causas.

Happy is he who can discover the cause of things.

Kevin Johnson
Guru
Guru
Posts: 7299
Joined: Tue Nov 22, 2005 5:41 am

Re: Excessive oil pressure

Post by Kevin Johnson » Sat Sep 22, 2018 8:40 pm

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:

Kevin Johnson
Guru
Guru
Posts: 7299
Joined: Tue Nov 22, 2005 5:41 am

Re: Excessive oil pressure

Post by Kevin Johnson » Sat Sep 22, 2018 8:49 pm

Types_of_oil_pumps.gif
Pressure_fluctuations.gif
Power_demands.gif
You do not have the required permissions to view the files attached to this post.

wilson1970
Member
Member
Posts: 92
Joined: Sun May 14, 2017 3:29 pm

Re: Excessive oil pressure

Post by wilson1970 » Sat Sep 22, 2018 8:56 pm

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?

Roundybout
Member
Member
Posts: 130
Joined: Tue Dec 29, 2015 8:09 pm
Location: NH

Re: Excessive oil pressure

Post by Roundybout » Sat Sep 22, 2018 9:08 pm

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

Kevin Johnson
Guru
Guru
Posts: 7299
Joined: Tue Nov 22, 2005 5:41 am

Re: balance grooves

Post by Kevin Johnson » Sat Sep 22, 2018 9:15 pm


gnicholson
Pro
Pro
Posts: 396
Joined: Tue May 06, 2008 9:59 pm
Location: kansas city mo

Re: Excessive oil pressure

Post by gnicholson » Sat Sep 22, 2018 9:36 pm

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?

User avatar
MadBill
Guru
Guru
Posts: 13593
Joined: Tue Nov 15, 2005 10:41 am
Location: The Great White North

Re: Excessive oil pressure

Post by MadBill » Sun Sep 23, 2018 12:04 am

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
Felix, qui potuit rerum cognscere causas.

Happy is he who can discover the cause of things.

User avatar
GuysMonteSS
Pro
Pro
Posts: 214
Joined: Mon Nov 19, 2007 5:35 pm
Location: Nova Scotia Canada

Re: Excessive oil pressure

Post by GuysMonteSS » Sun Sep 23, 2018 6:28 am

Melling also makes anti cav pumps for both the sb and bb.
Those ones have a C at the end of the part number.
Guy
'86 Monte SS,513 BBC,AFR heads,Bullet solid roller cam,Doug Nash 4+1 5 speed,Hurst Inline Shifter,Ford 9 inch Rearend.

Monza Harry
New Member
New Member
Posts: 34
Joined: Tue Sep 16, 2014 7:46 pm

Re: Excessive oil pressure

Post by Monza Harry » Sun Sep 23, 2018 7:24 am

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

pdq67
Guru
Guru
Posts: 7810
Joined: Thu Mar 04, 2010 8:05 pm

Re: Excessive oil pressure

Post by pdq67 » Sun Sep 23, 2018 9:56 am

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...

pdq67

GRTfast
Guru
Guru
Posts: 1090
Joined: Wed Jul 05, 2017 8:26 am

Re: Excessive oil pressure

Post by GRTfast » Sun Sep 23, 2018 1:37 pm

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:

wilson1970
Member
Member
Posts: 92
Joined: Sun May 14, 2017 3:29 pm

Re: Excessive oil pressure

Post by wilson1970 » Sat Sep 29, 2018 2:37 pm

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.

swampbuggy
Expert
Expert
Posts: 798
Joined: Mon Apr 04, 2011 8:54 pm
Location: central Florida

Re: Excessive oil pressure

Post by swampbuggy » Sun Sep 30, 2018 10:22 pm

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. :)

CGT
Guru
Guru
Posts: 1312
Joined: Sun May 10, 2009 12:29 pm

Re: Excessive oil pressure

Post by CGT » Mon Oct 01, 2018 9:43 am

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.

Post Reply