Welcome, Guest. Please login or register.
September 18, 2014, 09:45:53 pm

Login with username, password and session length
Team Z Motorsports
Tech Section
* SBFTECH Membership Required *
412853 Posts in 35330 Topics by 8821 Members
Latest Member: Connor926
Search: Advanced search
Advertiser Inquiries
+ SBFTECH.com Experienced Small Block Ford Tech
|-+ General Tech
| |-+ General Tech
| | |-+ Oil Pressure or Oil Flow - which is more important?
0 Members and 1 Guest are viewing this topic. « previous next »
Pages: [1] 2 3 ... 5 Go Down Print
Author Topic: Oil Pressure or Oil Flow - which is more important?  (Read 6589 times)
Joel5.0
El Hombre
Administrator
Big Block
*****
Offline Offline

Posts: 21463


Location: Puerto Rico
Miracles?.... by appointment only!


« on: August 22, 2010, 05:21:40 pm »

Looking at some OEM specs this morning for one of the cam core material threads, I noticed something that really made me go  Hmmmmm + WTF + YESSS at the same time. I notice a lot of threads in which oil pressure becomes a concern when anything below 30 psi (and many times less) are observed with the engine idling and hot.

I've always been a "pressure is above 12 psi and no engine noises are present = OK!, it's good to go anywhere" type of guy for the windsor engine. Sometimes I was given the Yeah Right! look.... are you crazy?    .....and the one I hate the most..... "but I was told by xxx that it is not normal". Even though my junk + other customers setups have run with ~12 psi engine hot @750 RPM for years under a little abuse.

Anyway.... here are some oil pressure specifications for some engines that even I couldn't believe.

1. 5.7L & 6.1L HEMI = 4 psi minimum at curb idle speed and 25 - 110 psi @3000 RPM
2. MOPAR 3.5L V6 = 5 psi minimum at curb idle speed and 45 - 105 psi @3000 RPM
3. GM LS2 6.0L = 6 psi minimum @1000 RPM,  18 psi @2000 RPM, 24 psi @3000 RPM
4. GM LS7 7.0L = 6 psi minimum @1000 RPM,  18 psi @2000 RPM, 24 psi @3000 RPM
5. GM LS1/LS6 5.7L = 6 psi minimum @1000 RPM,  18 psi @2000 RPM, 24 psi @3000 RPM

So... which one is more important?...... oil pressure or flow?
Logged

ACRONYMS:
LUK  LMK  JIC  BTSTDTRT  YCYDYP  NFI-YTM  SPOBI, and the classic... DILLIGAS

'86 Mustang GT, X-303 cam, Holley DP 700, RG Tran., 289 Heads   Ford Smilie 2


Quote from: Joel5.0
The right to be stupid is inalienable for sure however, there is no such thing as a right to impose stupidity onto others
Great Thoughts will Overwhelm a Feeble Mind
There is never money to do it right, but there's always money to do it over.
Knowledge based on external evidence is unreliable.
He, who doesn't ask, does not deserve an answer.
A mind is like a parachute it only works when it is open.  (oldmanjoe)
If you can't explain it simply, you don't understand it well enough. (Albert Einstein)
Tuning on a Dyno for the track, is like swim practice in a bathtub.
I can explain it for you, but I can't understand it for you. (90lxcoupe)
The proof of understanding is the ability to explain it. (H. Torruella)
Ignorance is bliss, but stupidity is orgasmic.
Fraud and falsehood only dread examination. Truth invites it. (Samuel Johnson)
The chaotic resistance of the opponents leads to the conclusion that they are not prepared to meet the challenge. The problem is already much more psychological then technological. [Bojidar Djordjev]
Individuals are rational and humane... Crowds are reactionary and barbaric. (Jason)
The person who says it cannot be done should not interrupt the person doing it. –Chinese Proverb
Nothing sways the stupid more than arguments they can't understand - Cardinal de Retz
David Claflin
Adv_SBFTechie
Big Block
****
Online Online

Posts: 7240


Location: Redneck Riviera (Ft Walton Beach Florida)

« Reply #1 on: August 22, 2010, 05:54:06 pm »

Aren't most of the new cars running 5W-20 now as compared to the older cars that were typically  10W-30 or 40?
Just throwing this out there, but would pressure play more of a part in the actual lubrication and the volume affect how the cooling aspect of the oil? Maybe not wording it right, just something that occured to me....
Logged

1990 Red LX, 306, 75MM, ported gt40's, Holley SMII, accufab longtubes, 3" exhaust, 4.10's
1985 LTD LX 302, ported TW's, XE-264 cam, ported Holley SMII, 75MM-R TB, accufab 1 3/4" longtubes, 4R70W, mach 1 brakes
1988 GT long term project
Joel5.0
El Hombre
Administrator
Big Block
*****
Offline Offline

Posts: 21463


Location: Puerto Rico
Miracles?.... by appointment only!


« Reply #2 on: August 22, 2010, 06:09:06 pm »

I've seen specs calling for 0w20 synthetic..... the 1994-95 Mustang GT with 5w20 (per Ford's TSB).

The way I see it is that oil flow takes precedence. I know, I know..... clearances however...... when a minimum oil pressure in a running engine is ensured (4, 10, 15 psi) main and rod bearings "lubricant cushion" is also ensured.... or are liquids compressible?  Hmmmmm
Logged

ACRONYMS:
LUK  LMK  JIC  BTSTDTRT  YCYDYP  NFI-YTM  SPOBI, and the classic... DILLIGAS

'86 Mustang GT, X-303 cam, Holley DP 700, RG Tran., 289 Heads   Ford Smilie 2


Quote from: Joel5.0
The right to be stupid is inalienable for sure however, there is no such thing as a right to impose stupidity onto others
Great Thoughts will Overwhelm a Feeble Mind
There is never money to do it right, but there's always money to do it over.
Knowledge based on external evidence is unreliable.
He, who doesn't ask, does not deserve an answer.
A mind is like a parachute it only works when it is open.  (oldmanjoe)
If you can't explain it simply, you don't understand it well enough. (Albert Einstein)
Tuning on a Dyno for the track, is like swim practice in a bathtub.
I can explain it for you, but I can't understand it for you. (90lxcoupe)
The proof of understanding is the ability to explain it. (H. Torruella)
Ignorance is bliss, but stupidity is orgasmic.
Fraud and falsehood only dread examination. Truth invites it. (Samuel Johnson)
The chaotic resistance of the opponents leads to the conclusion that they are not prepared to meet the challenge. The problem is already much more psychological then technological. [Bojidar Djordjev]
Individuals are rational and humane... Crowds are reactionary and barbaric. (Jason)
The person who says it cannot be done should not interrupt the person doing it. –Chinese Proverb
Nothing sways the stupid more than arguments they can't understand - Cardinal de Retz
juiced coupe
Six figures worth of don't give a f*ck
Global Moderator
Big Block
*****
Online Online

Posts: 6269


Location: Pascagoula, MS
The land mass between New Orleans and Mobile


« Reply #3 on: August 22, 2010, 08:18:01 pm »

I copied this from the other thread where this started. I also copied Joe's response in that thread.

Flow...........

The junk engine in the Coupe now, has had cruising(2500-3000 rpms) oil pressure around 24-26lbs, and idle it hits 10-12. Thats when hot and with 20w50 and quart of Lucas oil stabilizer. With out the lucas the pressure reads at about  8-10 at idle and around 20 cruising. I worried my ass off for a while. Close to 2 years really. Thats when I bought the car. No noise from the valve train. And filters always look good.  I stopped worrying.................... Still driving that junk everday. 



I like flow too. My junk only has about 15# at a fast idle and 55# at WOT, with 5w20. When I built my engine, I blended and smoothed as much of the oil passages as I could get to. I also opened up the oil holes in all my main bearings to match the passages in the block. All of this would contribute to increasing flow and therefore reducing pressure. All of this was done in addition to deburring and blueprinting a standard volume pump.
Logged

Just a 12 second car with a 11 second engine.....that runs 10s
http://sbftech.com/index.php/topic,20009.0.html

Quote from: Monte Smith
Bottom line, if it was the hot ticket, the fast guys would do it.............they don't

You might need some Titanium rods and a flow bench!  LMAO on floor
69 Merc
The Ricer King
Adv_SBFTechie
Big Block
****
Offline Offline

Posts: 13340


Location: OC, CA

« Reply #4 on: August 22, 2010, 08:27:41 pm »

Sheesh!  My Merc gets maybe 10psi at a hot idle and 40psi at WOT.  It's been that way for a few years now -- I used to be worried but not anymore.
Logged

Robert's 1969 Mercury Montego (FordStrokers 408W, QFT 850cfm RQ-AN, Super Victor, 2" aluminum open spacer, CamMotion HR .624/.609 251/256 108, 1-3/4" x 3" headers, Broader Performance RmV/B under a C6/4R100 behind a 8"/9" billet 5500 stall, 9" 4.56 Detroit Truetrac, M/T ET radial streets 315/60-15 on 10" rims)

The Merc started here = http://sbftech.com/index.php/topic,27178.0.html

Irwindale Speedway 1/8 mile (1st time at a track!) = 7.647 @ 90.78mph with a crappy 1.878 sixty foot (3850# race weight)

Present day Merc = http://sbftech.com/index.php/topic,34648.0.html


Except that engine building (properly) is a labor intensive industry.  Who do you think does all the measuring and machining?  Little engine shop fairies?  Not to mention assembly, mock up and parts fitting.

At Woody's level you are not just paying for his labor but for his skill set as well.

Thanks FordStrokers 408W, Westminster Performance Transmission (W.P.T.) transmissions, TCS Performance converters, Broader Performance valvebodies and last but not least a BIG thanks (always) to my friends here and abroad in the World!
F1 guy
Stroked Small Block
****
Offline Offline

Posts: 252


Location: Winona, MN
'48 F-1 upgraded one step at a time


« Reply #5 on: August 23, 2010, 05:21:44 pm »

I like flow too. My junk only has about 15# at a fast idle and 55# at WOT, with 5w20. When I built my engine, I blended and smoothed as much of the oil passages as I could get to. I also opened up the oil holes in all my main bearings to match the passages in the block. All of this would contribute to increasing flow and therefore reducing pressure. All of this was done in addition to deburring and blueprinting a standard volume pump.
[/quote]

Opening up the oil holes and massaging the oil passages would contribute to increased flow and reduced pressure? This made me go  Wonder, Ponder. If the pump is continuously pumping, regardless of RPM range, would it not produce the same pressure and same flow, regardless of massaged passages and opened/chamfered oil holes?
Logged

Remember...always keep your dipstick lubricated.
69 Merc
The Ricer King
Adv_SBFTechie
Big Block
****
Offline Offline

Posts: 13340


Location: OC, CA

« Reply #6 on: August 23, 2010, 05:32:47 pm »

I like flow too. My junk only has about 15# at a fast idle and 55# at WOT, with 5w20. When I built my engine, I blended and smoothed as much of the oil passages as I could get to. I also opened up the oil holes in all my main bearings to match the passages in the block. All of this would contribute to increasing flow and therefore reducing pressure. All of this was done in addition to deburring and blueprinting a standard volume pump.


Opening up the oil holes and massaging the oil passages would contribute to increased flow and reduced pressure? This made me go  Wonder, Ponder.

 If the pump is continuously pumping, regardless of RPM range, would it not produce the same pressure and same flow, regardless of massaged passages and opened/chamfered oil holes?

Same pump -- try a straw first and then switch to a fireman's hose.
Logged

Robert's 1969 Mercury Montego (FordStrokers 408W, QFT 850cfm RQ-AN, Super Victor, 2" aluminum open spacer, CamMotion HR .624/.609 251/256 108, 1-3/4" x 3" headers, Broader Performance RmV/B under a C6/4R100 behind a 8"/9" billet 5500 stall, 9" 4.56 Detroit Truetrac, M/T ET radial streets 315/60-15 on 10" rims)

The Merc started here = http://sbftech.com/index.php/topic,27178.0.html

Irwindale Speedway 1/8 mile (1st time at a track!) = 7.647 @ 90.78mph with a crappy 1.878 sixty foot (3850# race weight)

Present day Merc = http://sbftech.com/index.php/topic,34648.0.html


Except that engine building (properly) is a labor intensive industry.  Who do you think does all the measuring and machining?  Little engine shop fairies?  Not to mention assembly, mock up and parts fitting.

At Woody's level you are not just paying for his labor but for his skill set as well.

Thanks FordStrokers 408W, Westminster Performance Transmission (W.P.T.) transmissions, TCS Performance converters, Broader Performance valvebodies and last but not least a BIG thanks (always) to my friends here and abroad in the World!
F1 guy
Stroked Small Block
****
Offline Offline

Posts: 252


Location: Winona, MN
'48 F-1 upgraded one step at a time


« Reply #7 on: August 23, 2010, 05:49:34 pm »

Awwww! Light bulb went on. Sort of like the difference between the size of a carb. 650 cfm vs. 850 cfm. Sucking air through a straw or a fire hose.
Logged

Remember...always keep your dipstick lubricated.
347HO
A-1 Super Genious / Director of Maintenance
Section Moderator
Big Block
****
Offline Offline

Posts: 12026


Location: Seattle, Washington
I believe they landed on the moon.


« Reply #8 on: August 23, 2010, 05:56:55 pm »

Awwww! Light bulb went on. Sort of like the difference between the size of a carb. 650 cfm vs. 850 cfm. Sucking air through a straw or a fire hose.
More like an 850 vs 1150
Logged




... it was REALLY revving at like 4K...
If I saw that thing in my rear view Im pulling over to let you by, I be scared of that thing Huh? i dont know wich car is uglier ur or mine?
Javier
Ugly?  Easy now -- that's my baby and it's got lots of unique character!  When I drop that built 445" stroker in it you won't have any time to "pull over to let me pass" because I'll have already blown past you when you figure out what the hell was that loud noise behind you . . .  
Joel5.0
El Hombre
Administrator
Big Block
*****
Offline Offline

Posts: 21463


Location: Puerto Rico
Miracles?.... by appointment only!


« Reply #9 on: August 23, 2010, 06:04:54 pm »

Check the video clip at http://sbftech.com/index.php/topic,19427.0.html .....
Logged

ACRONYMS:
LUK  LMK  JIC  BTSTDTRT  YCYDYP  NFI-YTM  SPOBI, and the classic... DILLIGAS

'86 Mustang GT, X-303 cam, Holley DP 700, RG Tran., 289 Heads   Ford Smilie 2


Quote from: Joel5.0
The right to be stupid is inalienable for sure however, there is no such thing as a right to impose stupidity onto others
Great Thoughts will Overwhelm a Feeble Mind
There is never money to do it right, but there's always money to do it over.
Knowledge based on external evidence is unreliable.
He, who doesn't ask, does not deserve an answer.
A mind is like a parachute it only works when it is open.  (oldmanjoe)
If you can't explain it simply, you don't understand it well enough. (Albert Einstein)
Tuning on a Dyno for the track, is like swim practice in a bathtub.
I can explain it for you, but I can't understand it for you. (90lxcoupe)
The proof of understanding is the ability to explain it. (H. Torruella)
Ignorance is bliss, but stupidity is orgasmic.
Fraud and falsehood only dread examination. Truth invites it. (Samuel Johnson)
The chaotic resistance of the opponents leads to the conclusion that they are not prepared to meet the challenge. The problem is already much more psychological then technological. [Bojidar Djordjev]
Individuals are rational and humane... Crowds are reactionary and barbaric. (Jason)
The person who says it cannot be done should not interrupt the person doing it. –Chinese Proverb
Nothing sways the stupid more than arguments they can't understand - Cardinal de Retz
mxracer652
I'm Brendan, not Brandon!
Big Block
*****
Offline Offline

Posts: 2898


Location: Pittsburgh, PA

« Reply #10 on: August 23, 2010, 06:28:46 pm »

But you can't have flow without pressure.   Wonder, Ponder

Oil is incompressible.  The orifices are fixed.  If pressure decreases,  so does flow.
Logged

86 LTD wagon, stock longblock 302 & 70mm turbo
95 Ranger + 302/362 + 4 link
http://sbftech.com/index.php/topic,26347.0.html
347HO
A-1 Super Genious / Director of Maintenance
Section Moderator
Big Block
****
Offline Offline

Posts: 12026


Location: Seattle, Washington
I believe they landed on the moon.


« Reply #11 on: August 23, 2010, 07:00:51 pm »

But you can't have flow without pressure.   Wonder, Ponder

Oil is incompressible.  The orifices are fixed.  If pressure decreases,  so does flow.
Oil pressure indication as we normally see it is just a "gee wiz make me feel good" indication.
You can have oil pressure and not have any flow to one or some parts of the engine.

But...   if you have delta P indication taken at the back side of the pump and down one or both, top, oil galleys, then you'll have somewhat useful indication.

IMO. 4 Eyed
Logged




... it was REALLY revving at like 4K...
If I saw that thing in my rear view Im pulling over to let you by, I be scared of that thing Huh? i dont know wich car is uglier ur or mine?
Javier
Ugly?  Easy now -- that's my baby and it's got lots of unique character!  When I drop that built 445" stroker in it you won't have any time to "pull over to let me pass" because I'll have already blown past you when you figure out what the hell was that loud noise behind you . . .  
Joel5.0
El Hombre
Administrator
Big Block
*****
Offline Offline

Posts: 21463


Location: Puerto Rico
Miracles?.... by appointment only!


« Reply #12 on: August 23, 2010, 07:51:09 pm »

What He Said....... of course oil flow will generate pressure in the lube system, it is designed that way. The main point is the extraordinary and worthless preoccupation, In My Opinion and experience, that oil pressure below 20 psi engine idling under hot conditions a lot of people have..... usually causing repairs where are not really needed or required.

If you re-check the OEM specs posted, you'll also see the 10 psi/1000 RPM spec busted for the LSx engines. IOW....... the oil flow requirements to ensure a reliable and durable running engine based on oil pressure readings, are most of the times exaggerated.
Logged

ACRONYMS:
LUK  LMK  JIC  BTSTDTRT  YCYDYP  NFI-YTM  SPOBI, and the classic... DILLIGAS

'86 Mustang GT, X-303 cam, Holley DP 700, RG Tran., 289 Heads   Ford Smilie 2


Quote from: Joel5.0
The right to be stupid is inalienable for sure however, there is no such thing as a right to impose stupidity onto others
Great Thoughts will Overwhelm a Feeble Mind
There is never money to do it right, but there's always money to do it over.
Knowledge based on external evidence is unreliable.
He, who doesn't ask, does not deserve an answer.
A mind is like a parachute it only works when it is open.  (oldmanjoe)
If you can't explain it simply, you don't understand it well enough. (Albert Einstein)
Tuning on a Dyno for the track, is like swim practice in a bathtub.
I can explain it for you, but I can't understand it for you. (90lxcoupe)
The proof of understanding is the ability to explain it. (H. Torruella)
Ignorance is bliss, but stupidity is orgasmic.
Fraud and falsehood only dread examination. Truth invites it. (Samuel Johnson)
The chaotic resistance of the opponents leads to the conclusion that they are not prepared to meet the challenge. The problem is already much more psychological then technological. [Bojidar Djordjev]
Individuals are rational and humane... Crowds are reactionary and barbaric. (Jason)
The person who says it cannot be done should not interrupt the person doing it. –Chinese Proverb
Nothing sways the stupid more than arguments they can't understand - Cardinal de Retz
wrparrish
4 Banger
*
Offline Offline

Posts: 10

Location: Fuquay Varina, North Carolina

« Reply #13 on: August 23, 2010, 07:53:58 pm »

There is an extremely in depth and informative article on this, written up by a auto enthusiast, and surgeon who specialized in blood flow through arteries.    I wont bother anyone by posting it here.

One thing ive always seen though, is that 10 psi  per 1,000 rpm of loaded engine operation is usually a good base.  Indicated by your referenced 18 psi at 2,000 rpm for a variety of motors. 

For example,  Ferrari on some cars does not recommend a specific weight of oil, only a desired pressure achieved during operation.

Ive always done the same thing on my motors,  looking for the right weights to give me around 60 psi @ 6,000 rpm   at 70 degrees celsius or better oil temperature.

Its a tough topic to really corner into one answer.
Logged
David Claflin
Adv_SBFTechie
Big Block
****
Online Online

Posts: 7240


Location: Redneck Riviera (Ft Walton Beach Florida)

« Reply #14 on: August 23, 2010, 09:15:04 pm »

I also opened up the oil holes in all my main bearings to match the passages in the block. All of this would contribute to increasing flow and therefore reducing pressure. All of this was done in addition to deburring and blueprinting a standard volume pump.
I've always wondered why the bearing holes were smaller then those in the block. Never thought to open the bearing hole up, but will in the future. I've seen low pressure at idle when I've had the evac pump hooked up usually 10 PSI or thereabouts at hot idle, made me somewhat nervous at first but then several on here said it was normal with an evac pump.
Logged

1990 Red LX, 306, 75MM, ported gt40's, Holley SMII, accufab longtubes, 3" exhaust, 4.10's
1985 LTD LX 302, ported TW's, XE-264 cam, ported Holley SMII, 75MM-R TB, accufab 1 3/4" longtubes, 4R70W, mach 1 brakes
1988 GT long term project
Pages: [1] 2 3 ... 5 Go Up Print 
« previous next »
Jump to:  



Powered by MySQL Powered by PHP Valid XHTML 1.0! Valid CSS!
Powered by SMF 1.1.18 | SMF © 2013, Simple Machines



408 Stroker