Topic: Oil Pump
in Forum: C3 Engines
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Lifetime MemberDeBerry, TX - USA
Joined: 2/27/2002
Posts: 1006
Vette(s): 1971 383 Stroker- mille miglia red...5 speed
I was talking to the guy that's building an engine for my '71 today. In the course of the conversation about components being used, he mentioned a high PRESSURE oil pump. When I asked him if a high volume oil pump wouldn't be better, he disagreed saying unless I had something like a 8 or 9 quart oil pan, I could chance pumping too much oil out of the pan and a high pressure pump would do a better job supplying lubrication to the upper parts of the engine. This is not word for word, but basically what was said. I know I've read more than once here that volume is perferred over pressure. Is this always true, or are there exceptions, like maybe a new engine? This guy is a reputable builder and probably more 'old school' than anything else.
I'm not sure I understand how you can have more volume without more pressure, but that doesn't surprise me. 
Whadda y'all think? Volume or pressure and why? He said he'd put what I wanted in it, but he recommended high pressure. Thanks for any advice....
Whadda y'all think? Volume or pressure and why? He said he'd put what I wanted in it, but he recommended high pressure. Thanks for any advice.... I know the voices aren't real, but they have some pretty cool ideas... 
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Volume should be thought of as how much oil is moved in a given period
of time such as 2 quarts per minute. Pressure is the unit of measure,
usually psi, at the exit point. For instance in your radiator and
cooling system, volume is very important "if" the cirulation created by
the water pump falls off. But if you are using a fluid to move
something, like with hydraulic cylinder, pressure is very important.
They are certainly related. I seems to me that a high volume oil pump
would aid in keeping the engine cooler. Circulating oil definitely
absorbs heat and dissipates it as it moves throughout the system. I
would seek a second opinion from someone with lots of experience in
building high performance engines.
Scott
ranger3 2006-11-20 16:26:26
Scott
Lifetime MemberModerator
Duncanville, TX - USA
Joined: 11/8/2003
Posts: 20214
Vette(s): #1-1974 L-48 4spd Cp Med Red Metallic/Black deluxe int w/AC/tilt/tele./p/w-p/b/
Am-Fm/map light National/Regional/Chapter NCRS "Top Flight"
#2-1985 Bright Red/Carmine Cp.L-98/auto
Member: NCRS, NCRS Texas, Corvette Legends of Texas
If you want to watch yer oil fiter shoot across the hiway, put a high pressure pump in there. If not, a high volume is whut you want.
The high volume pump has longer gears, and therefore has the ability to move more volume than the regular pump. You can change the spring in the pump and make it high pressure, or even just change the pressure a little. You do NOT want a high pressure pump in a street car, imo. It's a waste of HP, for one, and you stand the chance of blowin the filter off in colder weather. Been there, done that, got the scars to prove it.
Joel Adams
C3VR Lifetime Member #56 
My Link 
(click for Texas-sized view!) NCRS
"Money can't buy happiness -- but somehow it's more comforting to cry in a CORVETTE than in a Kia"
If you turn the water on just a little bit to your garden hose and wait a little while before you open the noozle, it sprays real fast then slows down to a small flow of water. That's high pressure, low volume.
Now turn the water on full, open the noozle, it will spray fast the whole time because you have more volume but the same pressure.
I'd go for the high volume pump, but the guy building your engine might not stand behind it if you tell him to use a high volume pump, if it blows up he may say, " I told you so."
I used to install a heavier spring to increase oil pressure on engines with lot's of clearance in the bearings, but did it with a high volume pump.
If you buy a good brand oil pump for that Vette, you can't go wrong, if the engines built right.
Good luck,
Denny
Lifetime MemberDeBerry, TX - USA
Joined: 2/27/2002
Posts: 1006
Vette(s): 1971 383 Stroker- mille miglia red...5 speed
[QUOTE=Adams' Apple]Dwain, Dwain, Dwain... 
don't you ever learn? 
[/QUOTE] Obviously not....so I'll just quit asking stupid questions...
don't you ever learn? [/QUOTE] Obviously not....so I'll just quit asking stupid questions...
I know the voices aren't real, but they have some pretty cool ideas...
Lifetime MemberIrving, TX - USA
Joined: 8/21/2004
Posts: 4273
Vette(s): #1 -1969 Corvette Coupe Riverside Gold, black interior,MN,A/C,350/350,PS,PB,window cranks.
#2 -2000 C5, black/black, 6 sp, Bose system & lots of buttons.
[QUOTE=longhorn294][QUOTE=Adams' Apple]Dwain, Dwain, Dwain... don't you ever learn?
[/QUOTE] Obviously not....so I'll just quit asking stupid questions...[/QUOTE]
don't you ever learn? [/QUOTE] Obviously not....so I'll just quit asking stupid questions...
[/QUOTE]
No questions are "stupid" Dwain, we're just learnin'. 
Your in the right spot! 
Your in the right spot! 
�����
My Link 
MICK - C3VR Lifetime Member #113
Okay here goes.
kstyer 2006-11-23 17:20:54
There is no such thing as a high pressure pump. Don't even think about arguing, there is no such thing. Yes you can find high pressure pumps in the catalogs, you can see the ads, you can buy something that claims to be, but I repeat, there is no such thing.
Pumps, any pump pumping anything, do not produce pressure. Period. Pumps produce volume. Period.
Pumps move material, and the more they move the more volume they produce. So where does pressure come from? Pressure is resistance to flow. If you take any pump and let it send it output into an unrestrained area it will produce a lot of flow, but there will be no pressure. The fluid will just spill in some quanity onto a no pressure surface.
Pressure is the result of the resistance to flow. If we try to channel the flow and create a resistance to the flow, pressure is created. The more the channel is blocked, the more pressure is created.
Likewise, if the resistance is the same, and we try to pump more flow with a highter volume pump, the greater volume can't get out, so the pressure climbs higher. So high volume pumps create more pressure due to the fact that the volume can't get out at the same rate it is getting in. Granted as pressure increased, flow through a restriction increases. IF it did not the pressure would build too high, and cause damage to a pump or flow area, seal, bearing etc. or the pump itself. Liquid does NOT compress, and must go some where, or damage will occour if the volume input continues. There MUST be some kind of release.
The relief comes in the form of a relief valve. This is nothing but a check ball held in place by a spring. When enough pressure if built up, the ball pushes back on the spring and allows fluid (oil in our case) to dump out of the pressure system. Again, in our case it just returns to the oil pan.
A high pressure pump is nothing but a pump with a stronger spring that requires more pressure before it dumps excess fluid out of the system. Some will dump at 60 psi, some at 80 psi, or higher. Many high performance (read high volume) pumps come with a selection of springs to install to create different maximum pressures in the system.
This only works if the pump can produce enough volume to create that much pressure. If the volume is low, it won't create that much pressure. Remember pressure is resistance to flow. If the engine is worn and oil passes through bearings and the like easier, it won't build as much pressure, and the pressure relief valve does nothing. Pressure never gets that high.
A high volume pump can make up for wear by suppling more volume to fill the space, and still more volume, which causes pressure to rise. Again it is limited only by the resistance to flow, the available flow from the pump, and the maximim pressure relief valve setting.
What is advertised as a high pressure pump is nothing but a high volume pump with a stronger relief valve spring already installed.
So what do you want?
High volume is almost always a good thing. High pressure is not. Pressure does not supply much extra lube protection. THe key is to have the volume there to create a lubrication cushion. In a good tight engine, the standard pump supplies all the volume necessary. In a performance engine with larger clearances, or a worn engine, the high volume pump is a very nice choice, but don't use the higher pressure relief spring.
Higher pressure can acutally cause damage to some engine components. Only in VERY VERY high pressure operation do you need higher oil pressure to ensure enough lube film between components. But now we are talking full fledged race engine, not ANYTHING you would run on the street. Stop to consider the punishment an over road truck diesel takes with 80,000 lbs up grades, and they can operate very nicely on 30 psi under full load, with no damage.
Don't go TOO high of a volume. The pressure will go through the roof, and anywhere it can find a place to leak out it will. And it will find places. You won't like it.
Go with a high volume pump with the standard pressure relief spring. You and the engine will both be happy.
Lifetime MemberDeBerry, TX - USA
Joined: 2/27/2002
Posts: 1006
Vette(s): 1971 383 Stroker- mille miglia red...5 speed
Thanks Ken... Very well explained. 
Think I have a firm handle on this pump situation now. I think I'll print your post and take it to my builder... he might learn something too. Or... maybe I won't... Anyway, I just didn't like the explanation he gave me. It just seemed to lack a common sense factor. So... high volume pump it is. Thanks again.... Dwain
Think I have a firm handle on this pump situation now. I think I'll print your post and take it to my builder... he might learn something too. Or... maybe I won't... Anyway, I just didn't like the explanation he gave me. It just seemed to lack a common sense factor. So... high volume pump it is. Thanks again.... Dwain I know the voices aren't real, but they have some pretty cool ideas...
Lifetime MemberModerator
Duncanville, TX - USA
Joined: 11/8/2003
Posts: 20214
Vette(s): #1-1974 L-48 4spd Cp Med Red Metallic/Black deluxe int w/AC/tilt/tele./p/w-p/b/
Am-Fm/map light National/Regional/Chapter NCRS "Top Flight"
#2-1985 Bright Red/Carmine Cp.L-98/auto
Member: NCRS, NCRS Texas, Corvette Legends of Texas
Apparently, my earlier comment offended Dwain, even tho it wasn't meant to be mean spirited. I am truely sorry, Dwain. Sometimes I just don't know when to shut the f up.
Joel Adams
C3VR Lifetime Member #56
My Link
(click for Texas-sized view!) NCRS
"Money can't buy happiness -- but somehow it's more comforting to cry in a CORVETTE than in a Kia"
I can attest that Joel meant well. He just gets his keyboard in a twist and means no harm. That Texas sense of humor. Dwain, forgive him. I'm sure Joel doesn't know this (until now) but quite some time ago he really ticked me off for a few days. Then I came to my senses and realized he was just being Joel, and we love him anyway. Besides he contributes a lot of good to the C3VR family. Believe it or not he's really kind of shy. He almost hid at PF.
kstyer 2006-11-23 22:38:04
There are no stupid questions, just some stupid answers. We have a lot of them. Look at some of the past threads such as "Calling Dr. Adams" we all got dumb on that one, but we had fun. It just means you are part of the family. And we are all glad to have you. Keep asking questions.
in Forum: C3 Engines
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