High Volume Oil pumps

[Vettefan87]

Anybody know of good high volume oil pumps that I can put into my 1987 Corvette? I dont have any internal mods I just need more oil pressure. Thanks


Justin

[vettepilot]

Anybody know of good high volume oil pumps that I can put into my 1987 Corvette? I dont have any internal mods I just need more oil pressure. Thanks


Justin

High volume may not = more pressure , how much pressure are you seeing now at an idle, and at about 1500 to 2000 RPM? Is this measured by a direct reading gauge, or is that what's on the instrument panal gauge? If it's not from a direct reading, before you go tearing into the engine to replace the oil pump, you might want to make certain that the oil pressure your'e reading is accurate.
Also, depending on the mileage and condition of the current oil pump, it might just need a new pressure relief spring to bump up the line pressure, that will also increase the volume of the flow by not allowing so much to blow off past the pressure relief valve, therefor increasing the pressure that you see.

vettepilot

[drags1998]

I would not run a HV pump unless you have a HV oilpan!!!!! If you really feel the need to increase the oil press. then use a High pressure pump. But , remember the more press. that you run, the more power you lose!!!!!!! IF the engine is in sound condition, a STOCK pump is ALL you need!!!!!! Just my .o2 worth Paul

[Ken]

Paul's right. A stock pump usually is good for most applications; a high volume or a high pressure pump isn't necessary unless the engine's going to be seeing some severe duty.

[Vettefan87]

I am going to put a direct gauge on it tomorrow and see if it is the same as what I see in the car. I am not tearing into the motor before checking it all out, I just wanted to get the ball rollin. So if I put a higher pressure pump on how much HP will I lose?

[vader86]

Didnt we just have an argument over HV pumps?

You dont need HV, I would get a Melling M55A, its what I use.
It'll give you all the pressure you need.

[Ken]

Didnt we just have an argument over HV pumps?

Nah! An argument? Here??

I knew we discussed this subject before - several times as a matter of fact.

[bradvette]

I've had my L98 engine modified, and run a new stock GM oil pump/pickup, and everything is 100% perfectly fine.

[SG4206]

I am going to put a direct gauge on it tomorrow and see if it is the same as what I see in the car. I am not tearing into the motor before checking it all out, I just wanted to get the ball rollin. So if I put a higher pressure pump on how much HP will I lose?

The additional internal pump drag from a higher pressure relief spring is very hard to register on back to back dyno pulls on a 300- 400 hp small block. The dynos repeatability tolerance is 1/2 - 1 % ; so at most you are using 2-4 hp. A high volume will show around an additional 5-8 hp. To be honest; the oil temp has more effect on hp than which pump is used.

[Vettefan87]

I got word from the shop today since the long weekend it has been a while. He said the lowest the pressure got was 28 pounds he said that the fans were on so im guessing the oil temp was around 180 or so. In my mind that is still to low on a brand new motor. Any other brands for high pressure oil pumps other then the one vader posted? Thanks


Justin

[drags1998]

Its quite clear that you just want more oil pressure, despite what has been recommended to you. If this is the case, call someone like MOROSO and order one of their HIGH PRESSURE springs. Just make sure that you use the BEST oil filter that you can AFFORD!!!!!! Also plan on warming up the engine each time you do a cold start!!!!! Also, If your running a stock camshaft,and are going to be running more than 70psi at 3000RPM this will put a large amount of stress on the distributer& camshaft gears. GOOD LUCK!!!!!!! Paul

[vettepilot]

Its quite clear that you just want more oil pressure, despite what has been recommended to you. If this is the case, call someone like MOROSO and order one of their HIGH PRESSURE springs. Just make sure that you use the BEST oil filter that you can AFFORD!!!!!! Also plan on warming up the engine each time you do a cold start!!!!! Also, If your running a stock camshaft,and are going to be running more than 70psi at 3000RPM this will put a large amount of stress on the distributer& camshaft gears. GOOD LUCK!!!!!!! Paul

Bingo.... I totally agree with this. There is such a thing as too much oil pressure. Remember if you are running essentially stock internals, and factory clearances then one must consider the following items affected by oil pressure: The oil filter, the lifters, (are designed to bleed down from a certain pressure, raising the oil pressure significantly alters lifter performance), the distributor shaft and it's camshaft mating gears may incure a higher torque load. Also, raising the oil pressure may not increase oil flow throughout the engine. If the oil clearances are still the same factory clearances, then you probably won't see a real flow benefit from higher pressures. Instead, what you might see are: pumped up lifters that alter valve train characteristics, the possibility of bursting oil filters because all the increased oil pressure can't find a place to go because the bearing clearances were not increased to accomodate the increased pressure.


vettepilot

[Hib Halverson]

Anybody know of good high volume oil pumps that I can put into my 1987 Corvette? I dont have any internal mods I just need more oil pressure. Thanks


Justin

A high volume oil pump will not raise your oil pressure appreciably, although, it will increase the volume of oil exiting the pump. In most cases of stock or near-stock engine all a high-volume pump does is increase parasitic power loss and increase oil temperature.

Neigher stock nor even mildly modified engines need a high-volume pump. The myth that they do is propagated by Melling and the other makers of aftermarket oil pumps.

The only thing the engine in your 87 needs is the stock pump, fitted with the high-pressure pressure relief valve spring listed in the GM Performance Parts catalog, PN 3848911. You don't even need to pull the pump to install that. Just remove the bottom plate of the pump and change the spring. In an engine in good condition, using 10W30 engine oil that spring usually provides 60 psi hot oil pressure at high rpm.

If you still have low oil pressure after changing to the spring listed above, you need to repair the engine.

[Ken]

Hib, I hope you won't mind if I add some words from Marlan Davis regarding differences between "high volume" and "high pressure" in relation to oil pumping systems. I mean no disrespect by quoting one of your fellow technical writers, but he reinforces what you have already stated, and it may drive the point home a little more. It seems this subject (volume vs pressure) needs to be addressed every so often ,eh?

The following is in the "Pit Stop" section of the new (October) issue of Hot Rod Magazine.

Question: What is the difference between high-volume and high-pressure oil pumps? Which is considered best for a street/strip car?

For every rule there's an exception: Some engines like the Buick 455 have notoriously inefficient oiling systems and need all the help they can get. It's almost standard procedure to increase Buick oil pump volume and pressure.

Because oil pumps can produce more than 150 psi, a spring-loaded pressure regulating valve is installed in the oil system to limit maximum oil pressure. Under normal pressure conditions, the spring holds the valve closed. Under extreme high-pressure conditions (for example, if the oil is cold), the valve opens because oil pressure pushes the spring back, overcoming the spring tension; some oil bypasses the oil galleries and returns to the oil pan. A high-pressure oil pump is, then, merely a standard oil pump with a higher-tension spring that doesn't allow the bypass valve to open until a higher pressure is reached.

But the pump is not solely responsible for producing engine oil pressure. System pressure and flow are also influenced by restrictions in the engine's oil passages, aided by oil viscosity and engine operating speed. The faster the pump turns, the greater the oil flow through the engine. The more oil that flows through a restricted area of the engine, the greater the pressure. These restrictions include main and rod bearing clearances, connecting rod side clearance, and the size of internal lifter orifices, pushrod cavities, and oil galleries. As these clearances increase, so does the capacity for more oil flow.

However, if the engine's need for more oil increases beyond the pump's ability to supply it, pressure drops. In such cases, a high-volume pump may provide a solution. Generally these pumps are physically larger to accomodate bigger gears and increased internal volume. Some engines with inefficient oil systems may benefit from a high-volume pump, but on engines with decent oil systems such as the Chevy V-8, the smart move is to control windage losses in the first place by running tight bearing clearances, enhancing oil drain-back to the pan, installing a good windage tray, using modern synthetic oil, and (assuming solid lifters and roller rocker arms) limiting top-end oil flow.

There's power to be had if you can get by running a standard-pressure/standard-volume oil pump. Turning a pump with a high-pressure spring or larger gears wastes power; some tests have shown a 10-15 hp loss running 100 psi oil pressure. In most engines, abnormally high oil pressure puts more drag on the oil pump, increases the chances of oil overpowering the piston rings, entering the combustion chambers and causing detonation, and in some cases may even shorten internal component life.

So how much oil pressure is sufficient? For years we've preached the 10 psi per 1000 rpm rule - under this guideline, the engine requires 60 psi at 6000 rpm, 70 psi at 7000 rpm, 80 psi at 8000 rpm, and so on. But nowadays it is not uncommon for race cars to run only 40-50 psi over 6000 rpm. At the low end, even 5-10 psi at no-load idle is okay (as long as any hydraulic lifters don't start to clatter).

Certainly a street/strip small-block engine that doesn't exceed 6500 rpm, running modern thin oil and tight bearing clearances, can get by with a pump of standard pressure and volume. If more pump capacity is needed, increased volume is generally safer than higher pressure if the oil pan has adequate capacity. Joe Mondello says he has seen increased cam wear, distributor gear problems, and bearing wash with a high-pressure pump, because the cold pressure on such a pump can hit 90 psi. He adds: "Excessive oil pressure takes more horsepower to run than adding volume to get the same given amount of oil into the engine."

[Edmond]

I think Justin had his motor rebuilt to stock specs.

I always thought the HV oil pumps were for racers. How much do they go for?