3 Types of Oil Pumps + Working Principle & PDF

Types of Oil Pumps

Types of Oil Pumps – Every aspect of oil and gas production necessitates the use of industrial pumps. They essentially aid in the movement of process fluids from one location to another.

For instance, pumps can move crude oil from a storage tank to a pipeline, and mud pumps can circulate drilling mud into a drill bit’s annulus and back to a storage tank for repurification.

Looking for Pumps Device & Equipment?

Here at Linquip you have access to all of it for free

Process fluids in oil and gas operations can be simple or complex. You’ll need an appropriate pump for your requirements depending on the type of material you wish to convey and the desired flow rate.

⇒ View a Comprehensive List of  Pumps for Sale and Their Suppliers ⇐

What Are Oil Pumps?

The oil pump is a mechanical mechanism that circulates oil to moving elements of an engine, such as bearings, camshafts, and pistons, in order to prevent wear and tear. It is one of the most important components of an engine’s lubrication system that must not fail or malfunction, or else the engine would break down.

An oil pump in a car performs the following functions:

Looking for Pumps Device & Equipment to Buy?

Here at Linquip you have access to all of it for free

  • Under pressure, oil is transferred to the engine’s key components.
  • The movement of engine lubricant around the engine is made easier.
  • Provides direction for the oil’s passage through the galleries and to various areas.
  • Aids in the return of heated oil to the reservoir’s cooler oil.
  • Maintains consistent oil circulation throughout the engine.
Types of Oil Pumps
Oil pumps are essential instruments in industry (Reference: tbk-jp.com)

Working Principle of Oil Pumps

An engine’s oil pump is unavoidable for lubrication, as engines must be adequately lubricated while operating. The oil pump is normally powered by the crankshaft and begins pumping oil as soon as the engine is started. Oil injectors are not used in some oil-free engines, such as two-stroke engines.

Oil travels from a strainer into the oil pump, then via the heat exchanger, where it is cooled. After cooling, the oil passes via the galleries to the engine’s moving components before returning to the sump. A little amount of oil is transferred to an injector when an engine is designed with one.

The gap between the cylinder wall and the piston rings is sealed by oil poured into the cylinder. This keeps the compressed air from escaping through the pistons, increasing the engine’s overall efficiency.

Oil pressure in an engine may reach 10 psi for every 1000 revolutions per minute (rpm), which is around 55-65 psi. The pressure on the crankshaft journal and bearing is substantially higher than the 50-60 psi established by the relief valve on the relative pump and can reach hundreds of psi.

The relative speeds of the crankshaft journal in feet per second, not rpm, cause this tremendous pressure. The bearing, bearing width, oil viscosity, and temperature are all taken into account, as well as the bearing clearance (leakage rate).

Low-speed engines have relatively big journals, as well as a small pump and pressure. This is due to the fact that pump pressure does not fill the hole and replenish the oil in the annular area as quickly as the leak starts.

Low pressure means that bearing leakage is greater than the pump’s supply rate.

The condition of the oil pump is shown by a gauge pressure indicator or warning bulb on the dashboard of a car. Depending on the oil in the engine or the engine’s health, there might be high or low oil pressure.

The high oil pressure in the front or main engine causes the oil plugs to blow out. On cold start-ups, high oil pressure signifies very high pressure, which arises owing to the engine’s design.

Low oil pressure can cause engine harm. It causes engine components to fail, beginning with the cam carrier bearings, which are located at the top of the engine. That is to say, the upper areas will be deprived of lubrication. Low pressure might induce liner/piston nip if the pistons contain crown jets. Low oil pressure can also cause the crankshaft and connecting rod to seize.

The following factors can contribute to low oil pressure:

  • Oil pump that is worn or malfunctioning, or a broken pressure release valve spring.
  • There isn’t enough oil in the engine, or there isn’t any at all.
  • The main bearings are worn out.
  • Fracture or obstruction of the oil gallery.

To find out more information on the working principle of oil pumps, watch this nice video.

Types of The Oil Pump

  • Twin Gear Pumps
  • Rotor Pumps
  • Front Cover Oil Pumps

Twin Gear Pumps

Twin gear pumps (also known as external pumps) are positioned within the oil pan on the engine’s bottom and pump oil using a pair of intermeshing gears. A shaft drives one gear, and the first gear drives the second gear. A shaft connected to the crankshaft, camshaft, or distributor shaft commonly drives the pump. As a result, the pump runs at half the engine’s speed. Pump gears rotate in opposing directions. This captures oil between the gear teeth and transports it from the pickup tube entrance to the pump outlet around the outside of each gear. The oil cannot flow rearward to the intake due to the tight clearances between the gears.

The clearances between the gears, the gears and the housing, and the ends of the gears and the pump cover all affect the oil pressure created by a Twin Gear oil pump. Small dimples have been bored into the tops of the gear teeth on this pump. The dimples serve as oil reservoirs, which help to keep the internal pump lubricated and decrease wear on the gears and pump cover.

Types of Oil Pumps
Various parts of a twin gear pump (Reference: northern-pump.com)

Rotor Pumps

An inner gear revolves within an outer rotor in rotor pumps (also known as “gerotor” pumps). In comparison to the outer rotor, the inner gear has one fewer lobe. The outer rotor is likewise placed slightly off-center to the inner gear, causing the outer rotor to spin at around 80% of the inner gear’s speed. This causes a bellows-like pumping motion, which sucks oil from the input port and pushes it to the output port. Pumping efficiency necessitates precise tolerances. Pumps of this sort can also be found in the crankcase.

Front Cover Oil Pumps

Oil pumps for the front engine cover (also known as internal/external pumps) are normally found in the front engine cover. This is a rotor pump with an inner driving gear and an outer rotor, but the inner gear is directly attached to the crankshaft. A separate pump drive shaft is not required with the direct drive technique. Because this pump rotates at the same speed as the engine, it produces greater pressure at idle than a camshaft or distributor-driven pump (which only turns at half engine speed). Many overhead cam engines, as well as late model pushrod engines, including Chevy LS engines and Ford modular V6 and V8 engines, employ this sort of pump.

The oil must travel a longer distance from the oil pan to the pump, which is one of the disadvantages of front-mounted oil pumps. When the engine is cold and initially started, this might impede the flow of oil. Lower viscosity motor oil (such as 5W-20 or 5W-30) is advised for many of these applications to ensure that oil reaches the pump more rapidly during cold weather.

It is not necessarily required to replace the complete front cover assembly when this type of pump becomes worn, as long as the pump housing inside the cover is not worn or destroyed. To renew the pump, a new driving gear may be fitted on the crankshaft, and a fresh rotor can be installed in the cover.

Another parameter to keep in mind with front-mounted pumps is that the pump rotor’s alignment within the housing is crucial. Before the housing mounting bolts are tightened, they must be perfectly aligned in the housing; otherwise, the pump may be damaged when the engine is initially cranked and started. To ensure that the pump rotor is centered within its housing, utilize shims or feeler gauges. If at all feasible, do this with the engine out of the car and the block on its end, with the crankshaft vertical rather than horizontal.

The crankshaft will be centered within the major bores as a result of this. The crankshaft will be resting on the lower main bearings and will not be completely centered in the main bores if the block is in the vehicle or installed on an engine stand with the crankshaft in a horizontal position. A front-mounted oil pump can be damaged by even a few thousandths of an inch off-center.

Common Failure on Oil Pump

An oil pump failure can cause catastrophic damage to a car, especially if the driver is unaware of the failure indications. When a problem arises in the engine, the oil light indication on the dashboard turns on, alerting the driver that there is an issue. An oil pump’s failure symptoms are as follows:

  • Low oil pressure: An oil pump that is malfunctioning or worn out will not be able to push oil through the system adequately. The low oil pressure will ensue, potentially causing engine damage although as indicated earlier in this post, there are various indicators of low oil pressure.
  • Increased engine operating temperature: because oil decreases friction, it acts as a cooling agent in a vehicle’s engine. When the pump is in good working order, the engine will run at a normal temperature since the oil flow will be steady. However, when the engine oil flow slows or stops, the components continue to be lubricated by hot oil that is not permitted to flow.
  • Noise: If a hydraulic lifter in a vehicle is not properly lubricated, it will begin to create noise. These tend to be silent when the oil pump is in good working order and the oil is adequately circulated. Lifters are incredibly costly to replace, which is why it’s critical that the engine never runs dry.
Types of Oil Pumps
Common failures of an oil pump (Reference: rxmechanic.com)

Oil Pump Replacement Options

A standard replacement oil pump should be enough for most engines. However, you might wish to consider a High Volume oil pump for some high-performance applications.

Longer gear sets are used in high-volume pumps to displace more oil. If you’re developing an engine with looser bearing clearances, a high-volume oil pump may flow 20 to 25% more oil than a stock pump to raise oil pressure at idle and compensate for greater bearing clearances (say .002 or more). For street engines, most bearing manufacturers recommend .0015 inches of space on the main and rod bearings and.002 to.003 inches for drag engines.

A stiffer relief valve is used in a high-pressure oil pump, which does not open until a greater pressure is attained (75 psi or higher). When the pump is spinning slowly, this sort of pump can offer more oil pressure at high RPMs, but it has no influence on idle oil pressure. Is it really necessary to put extra strain on yourself? The parasitic drag caused by the pump increases as the pressure rises.

That’s why many NASCAR teams use low oil pressure (5 PSI for every 1000 RPM) yet tighter bearing clearances and synthetic motor oils with low viscosity (such as 0W-20). More horsepower at the flywheel implies less horsepower turning the pump.

Priming A New Oil Pump

Never replace an oil pump without first filling the pump housing with oil. This is especially true for oil pumps that are driven by the crankshaft from the front.

When the engine is cranked, the crankcase-mounted oil pumps, which are placed inside the oil pan on the footing of the engine, are immersed in oil and self-prime fast. This is not the case with front-mounted oil pumps, which are high and dry and located far away from the oil pan.

Oil should be poured into the pump housing before it is placed for front-mounted oil pumps. It is then necessary to prelubricate the pump by removing the nearby oil galley plug and injecting oil into the gallery using a hose and funnel BEFORE the engine is started. You may also use a pressure oiler to prime the system before starting the engine at an oil gallery plug or the oil pressure sending unit fitting. If the pump fails to create any oil pressure, it may cause a dry start, causing damage to the pump and/or crankshaft bearings.


The oil pump’s principal function is to circulate pressurized lubricating oil throughout the engine’s working components. The engine’s temperature was likewise maintained by the pumped oil. Although the many types of oil pumps have been briefly explained here, a more in-depth examination of each is required to properly comprehend the benefits and drawbacks of each technology.

You are encouraged to visit the oil pump for sale on the Linquip website to find an appropriate oil pump for your application among a lot of companies and manufacturers of oil pumps.

FAQs about Oil Pumps

1. How long do oil pumps last?

To find out how long your oil pump should last, look it up in your owner’s handbook or on the manufacturer’s website. It’s important to remember that it’s either time or miles, whichever comes first. A standard oil pump should last between 5 and 5.84 years if you use 12,000 miles per year as a benchmark.

2. What controls the pressure in the oil pump?

Bearing tolerances in the engine and the pressure regulating valve assembly in the oil pump control the oil pressure.

3. What causes oil pump failure?

Oil pollution, such as gasoline, metallic wear particles, or any other potentially infectious materials in a vehicle’s oil, can cause an oil pump to fail over time.

4. Do oil pumps fail?

Even though the oil pump appears to be robust, it might fail with time. When the oil pump starts to wear down, it’s critical to notice the indicators since this implies the engine and its components won’t be lubricated.

5. What portion drives the oil pump?

The crankshaft drives the majority of oil pumps. The pump in this illustration rests on top of the crankshaft’s snout, where its internal gear is directly operated. Positive displacement pumps are used in all oil pumps because the amount of oil that exits equals the amount that enters.

Buy Equipment or Ask for a Service

By using Linquip RFQ Service, you can expect to receive quotations from various suppliers across multiple industries and regions.

Click Here to Request a Quotation From Suppliers and Service Providers

Read More on Linquip

Print Friendly, PDF & Email
Looking for Pump Device & Equipment Prices?

Here at Linquip you can send inquiries to all Pump suppliers and receive quotations for free

Leave a Comment

Your email address will not be published. Required fields are marked *