Oil pump effectiveness as it ages

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newbe46

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On the forum I see a lot of discussions or sometimes passionate debate on which oil brand to use, which viscosity, the perfect OCI, what you can deduce from a UOA, and etc.

However, I can't seem to find much on what an oil pump does to engine wear or in fact a weakened oil pump. Perhaps I just did not look far back enough.

My question is, engine oil requires the oil pump to reach different parts of the engine. The oil flow has to overcome the gravity and viscosity. The kinetic energy has to come from the oil pump to provide oil flow.

If as the oil pump ages and does not provide the specified oil flow or oil pressure, does it not incur more engine wear?

I think there is a difference between flow and pressure, I don't mean to use these two attributes interchangeably. I don't want to get an PhD or read two hours of Wikipedia before posting this question, so my apologies if this confuses you.
 
Engine oil pumps wear like anything else, the more they wear the less oil pressure they produce and the more wear on the engine to the point of engine damage in some cases.

Old Buick owners (and a others) are well aware of this phenomenon, gear pump with an aluminum timing cover as a housing, some got so bad there was almost no oil pressure being generated by the pump and bearing failure was imminent unless you did something about it right quick once the oil light started flickering at hot idle.

Newer crank driven pumps are much better and can last the life of the engine but they are pre filter so it doesn't matter how efficient the oil filter, every particle has to go past it to get to the filter. The most important thing to a long from it is the air filter and a tight crankcase vent system.

Back to those old cars, every engine that used a carb back then was almost always missing the gasket between the carb and filter housing and along with poor crankcase vent system filtering allowed a lot of unfiltered wear causing particles to enter the engine.

Sorry its a little more long winded response than you asked for.
 
Originally Posted By: Trav
Engine oil pumps wear like anything else, the more they wear the less oil pressure they produce and the more wear on the engine to the point of engine damage in some cases.

Old Buick owners (and a others) are well aware of this phenomenon, gear pump with an aluminum timing cover as a housing, some got so bad there was almost no oil pressure being generated by the pump and bearing failure was imminent unless you did something about it right quick once the oil light started flickering at hot idle.

Newer crank driven pumps are much better and can last the life of the engine but they are pre filter so it doesn't matter how efficient the oil filter, every particle has to go past it to get to the filter. The most important thing to a long from it is the air filter and a tight crankcase vent system.

Back to those old cars, every engine that used a carb back then was almost always missing the gasket between the carb and filter housing and along with poor crankcase vent system filtering allowed a lot of unfiltered wear causing particles to enter the engine.

Sorry its a little more long winded response than you asked for.



This is not long winded at all and your response is much appreciated.
 
Originally Posted By: newbe46
I think there is a difference between flow and pressure, I don't mean to use these two attributes interchangeably.


Pressure and flow aren't the same thing, but they are connected to each other dependaning on the fluid viscosity and flow resistance of the system. That's why in an engine oiling system, the oil pressure at a constant RPM will go down as the oil warms up and becomes thinner. Or if the main and rod bearing clearances get larger from wear the oil pressure will go down.

And yes, oil pumps can slowly wear too which will lower the observed oil pressure assuming other factors haven't changed. Any time a drastic change in oil pressure happens it should be immediately investigated.

I think any oil pump wear would be very slow if regular oil changes are done. Most engine manufacturers specify a minimum oil pressure based on certain conditions (oil viscosity, oil temp & engine RPM). Oil pressure could slowly drop with high mileage due to all engine components slowly wearing out with mileage. Engines that are abused with extreme lack of maintenance will suffer with more wear
 
Once the pump has worn to the extent that it can no longer provide adequate flow and maintain the correct pressure then it will go rapidly donhill from then on. Having said that it will be a only after many thousands of miles on a maintained to a reasonable standard, not ocd fresh oil and filter every 1000 miles, but looked after like your work clothes.

Claud.
 
I don't think oil pumps typically wear out for a long time on almost any engine. My 83 Caprice has 228k miles on its original 305 and I don't believe it has any oil pressure issues yet, although I haven't put a real gauge on it. I never hear of them failing on anything.
 
The Ford Modular engines use an oil pump that has a sheet metal backing plate. That plate bends outward and releases oil! Of course, Ford gauges are really just indicating that there is pressure, and do not indicate actual pressure.

The result is that some engines suffer poor oil flow and damage. I believe Melling makes a higher quality replacement.

Universally, the folks who get longer Modular engine life, use a more viscous oil.
 
Originally Posted By: Cujet
The Ford Modular engines use an oil pump that has a sheet metal backing plate. That plate bends outward and releases oil! Of course, Ford gauges are really just indicating that there is pressure, and do not indicate actual pressure.

The result is that some engines suffer poor oil flow and damage. I believe Melling makes a higher quality replacement.

Universally, the folks who get longer Modular engine life, use a more viscous oil.


I have a very noisy 5.4 that I run 5w-40 in. It has 110K on it. Hoping for another 30 or 40 out of it then I can get it rebuilt! Along with a lot of stuff the truck needs
 
Originally Posted By: Trav
The most important thing to a long from it is the air filter and a tight crankcase vent system.


A tight crankcase vent, does that mean replacing the PCV periodically?
 
Sure. In the most basic system vacuum draws the fumes out and on the other side filtered air must flow freely through the engine to prevent a vacuum inside the engine case which could apply negative pressure to the seals and cause leaks.
On old systems the little almost worthless crankcase breather was pre air filter, not very good. Oil dipsticks had no O ring or seal to seal the tube.



Most newer cars draw the air for the crankcase post air filter which is much better, the problem with both is the plumbing, old and cracked hose may not cause any drivability issues or CEL yet allows damaging particles into the crankcase.
Its a good idea to check the hoses for cranks and poor fitment, missing or loose clamps and make sure the air filter is replaced on schedule or when dirty and it fits properly and tight, no missing screws or clips.

If the dipstick has an O ring or seal as on VW plastic tubes make sure its there and in good condition. This is a little thought of location for unfiltered air ingress. Changing the PCV insures the crankcase is being properly ventilated and reduce the possibility of sludge/deposit buildup and lowers the chance of seal leaks due to positive crankcase pressure.
 
I read about them but haven't run into one yet. Are these belt driven, electronically controlled mechanical or both?
if it can compensate for wear they most have some headroom built in, I wonder how long its going to take the ecm tuners to utilize 100%.
 
Can I just say I've never seen an oil pump replacement fix a low oil pressure problem. Every engine I've seen with low oil pressure was worn out.
 
These types of cover mounted pumps had all sorts of issues and when repaired fix low pressure issues. This was so common on Buick engines the aftermarket offered longer gears, SS sleeve inserts, spacer plate and higher relief covers as well as feed mods.

There were aluminum body in the pan pumps also that wore badly but because most cars had idiot lights the lower oil pressure went unnoticed for a long time and engines wore, so yes by the time the iffy pump was found out the engine was too far gone many times.
Being a mechanic in the 70's working on 60's era cars was a different time.



 
Originally Posted By: caprice_2nv
I don't think oil pumps typically wear out for a long time on almost any engine. My 83 Caprice has 228k miles on its original 305 and I don't believe it has any oil pressure issues yet, although I haven't put a real gauge on it. I never hear of them failing on anything.

+1, on typical cast iron housing.
It's quite a differrent story on aluminium pump housing though.
 
Originally Posted By: Trav
I read about them but haven't run into one yet. Are these belt driven, electronically controlled mechanical or both?
if it can compensate for wear they most have some headroom built in, I wonder how long its going to take the ecm tuners to utilize 100%.


The only one's I'm familiar with are on Gen 5 GM V8's.
Driven by the crankshaft like Gen 3 & Gen 4, The pumps displacement (Slide) is controlled by a PWM Solenoid. Does Not use a pressure regulator valve. But does have a pressure relief valve.

They are very similar to a 4L60E/6L80E front pump, The rotor is a little thinner but quite a bit larger. I didn't calculate max displacement, But I would guess it could produce similar pressures.....250-270 PSI. I'm sure the Blow-Off is set way lower than that.

HP-Tuners doesn't have the oil pump control tables available yet, At least not the last time I checked. I imagine it's just Target Oil Pressure vs Temp vs RPM.

Yes, It will be interesting!
 
Holy cow over 200 psi available. I guess they wont be trying to utilize 100% pressure and flow, 1/4 of that would be a dream for some of the old engines.
Thanks for the info, I have to read up on it then go have a look at one down at the dealer when they have one apart.
 
Originally Posted By: dishdude
Can I just say I've never seen an oil pump replacement fix a low oil pressure problem. Every engine I've seen with low oil pressure was worn out.


I got lucky on my Jeep 4.0. It had low oil pressure from a pump issue.

The pump fell off! But since the bottom of the pickup is like 1/8'' away from the pan, it would still get driven from the cam and get some oil to the engine!

Tightened it back up and suddenly it had normal oil pressure again!
 
are the gears in oil pumps in the older pumps of a different hardness. then the newer pumps.
 
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