Help with low oil pressure

[moparmike68]

This might be a possibility.

Understanding Engine Oil Aeration​

What is Engine Oil Aeration?​

Engine oil aeration occurs when air bubbles mix with engine oil, leading to a frothy or foamy consistency. This can disrupt the oil's ability to lubricate engine components effectively, resulting in increased wear and potential engine damage.

Causes of Engine Oil Aeration​

Several factors contribute to engine oil aeration:

• High Engine Speeds: Rapid engine revolutions can agitate the oil, introducing air bubbles.
• Improper Oil Levels: Overfilling or underfilling the oil reservoir can cause aeration. Overfilled oil can churn excessively, while underfilled oil may draw in air.
• Faulty Oil Pumps: Malfunctioning oil pumps can fail to maintain proper oil flow, allowing air to mix with the oil.
• Oil Quality: Low-quality oil or incompatible oil types can lack anti-foaming properties, increasing the risk of aeration.

Effects of Engine Oil Aeration​

Aerated oil can lead to several issues:

• Reduced Lubrication: Air bubbles disrupt the oil film, increasing friction and wear on engine parts.
• Engine Overheating: Aerated oil does not dissipate heat effectively, leading to higher temperatures and potential thermal degradation.
• Oil Degradation: Exposure to air accelerates oil oxidation, resulting in sludge and varnish formation.
• Pressure Loss: Aeration can cause cavitation in the oil pump, leading to a loss of oil pressure and potential oil starvation.

Prevention of Engine Oil Aeration​

To minimize aeration:

• Maintain proper oil levels.
• Use high-quality oil that meets manufacturer specifications.
• Regularly check and maintain oil pumps and lubrication systems.
• Avoid prolonged high-speed driving when possible.

Understanding and addressing engine oil aeration is crucial for maintaining engine health and performance.

I don’t think it is an aeration problem, but that’s only my opinion based on the condition of the oil when I check it on dipstick after driving and there is no frothy or bubbly appearance to the oil. Also I do have a windage tray installed so they had to be better than no tray.

 

[Challenger RTA]

I don’t think it is an aeration problem, but that’s only my opinion based on the condition of the oil when I check it on dipstick after driving and there is no frothy or bubbly appearance to the oil. Also I do have a windage tray installed so they had to be better than no tray.

A bad oil pump can churn up the oil. Oil pick up tube not sealed. Oil sump location to closes or to far. You just have to go through it one step at a time. Pull valve covers, prime see what you have.

 

[moparmike68]

A bad oil pump can churn up the oil. Oil pick up tube not sealed. Oil sump location to closes or to far. You just have to go through it one step at a time. Pull valve covers, prime see what you have.

Yeah it just sucks to think that I have to remove the pan and windage tray with the engine in the car and how difficult it will be to put it all back in with no leaks. Also if there is nothing obvious after getting into the pan.🫩

 

[Ohiowoodchuck]

Do what challenger rta mentioned above. You just have to pull the valve covers and the distributor. Get a good heavy duty drill and see what kind of pressure you can build.

 

[moparmike68]

Yeah it just sucks to think that I have to remove the pan and windage tray with the engine in the car and how difficult it will be to put it all back in with no leaks. Also if there is nothing obvious after getting into the pan.🫩

Do what challenger rta mentioned above. You just have to pull the valve covers and the distributor. Get a good heavy duty drill and see what kind of pressure you can build.

Yeah planning to do that and I have another oil gauge that I plan to use to see if I get a different reading than the gauge I have been using in the car.
Thanks

 

[Ohiowoodchuck]

Did you replace the cam bearings and install a new cam or reuse the old one.

 

[moparmike68]

Did you replace the cam bearings and install a new cam or reuse the old one.

Did you replace the cam bearings and install a new cam or reuse the old one.

I would assume and hope that the guy who did my engine installed a new cam and bearings.

 

[pschlosser]

Told him I wanted the engine internals reassembled so that all I would have to do would be install the valve covers, intake , carb, timing chain cover etc myself. I assumed that the internals were all new and gone through.

"blue-printing" the engine is what most want done to their engines during a rebuild. At the factory, (or the engine-builder for the factory) they are mass producing engines, and cannot take the time to make sure everything is as perfect as possible. they get things within a reasonable tolerance, they get things close, and often, that is good enough for most passenger engines to go 100,000s of miles before they fail.

The blue printing typically includes getting things balanced, every single bearing (designed to wear and someday be replaced) actually getting replaced, measured with more accuracy, and assembled with a great deal more precision and care, than was done by the factory. Blue printed engines typically rev higher, produce more power, and last longer than their mass produced cousins.

But when a worn engine is taken to "a rebuild shop" with vague instructions, it may not be treated with the level of care and precision we all hope for. In many cases, their objective is to produce a result satisfactory to the customer with the greatest profit.

If you look at this from another perspective, we can ask what the least amount of work must be done, to get the engine running at factory specs, again. The list can be pretty short, a valve job and a new set of rings, in some cases, not even that.

So in the end, it doesn't sound like we know what level of rebuild was done to your engine. It may be possible the crankshaft and cam bearings were never replaced. It is hard to say without more data.

When you began your post suggesting you have a (I admit I presumed a blue-printed and FULLY rebuilt) engine, acting worn out after only 1000 miles, I think many of us are thinking about premature wear and an oiling issue.

Going from a not-smoking engine to a smoking one in 1000 miles does suggest something in there is worn. Any major oiling issues, or issues where little or no oil flow was occurring, may not even last 1000 miles. It's not a big deal, and I'm not trying to be critical of the OP, or their engine.

The advice I may give for a "blue printed" engine with 1000 miles on it, versus a "freshened-up" engine with (potentially) 200K miles on some of the internal wearing parts, is going to be different.

Unless you find something wrong with your oiling, you may have to live with the engine smoking and the wear. If and when you decide to have the engine "rebuilt" you may want to be clear about what you want.

If you never saw the oil light come on, while revving your engine in a burnout or flooring it up an on-ramp, chances are good you did NOT starve the engine for oil by running it dry. To make an engine wear out fast, requires running it hard and/or frequently with less oil (or old oil) than it needs.

 

[6PKRTSE]

Since new and/or different oil pumps have been changed and tried without much improvement. Without knowing bearing clearances or tearing it down to measure everything. How about a cracked pick-up tube.

 

[moparmike68]

"blue-printing" the engine is what most want done to their engines during a rebuild. At the factory, (or the engine-builder for the factory) they are mass producing engines, and cannot take the time to make sure everything is as perfect as possible. they get things within a reasonable tolerance, they get things close, and often, that is good enough for most passenger engines to go 100,000s of miles before they fail.

The blue printing typically includes getting things balanced, every single bearing (designed to wear and someday be replaced) actually getting replaced, measured with more accuracy, and assembled with a great deal more precision and care, than was done by the factory. Blue printed engines typically rev higher, produce more power, and last longer than their mass produced cousins.

But when a worn engine is taken to "a rebuild shop" with vague instructions, it may not be treated with the level of care and precision we all hope for. In many cases, their objective is to produce a result satisfactory to the customer with the greatest profit.

If you look at this from another perspective, we can ask what the least amount of work must be done, to get the engine running at factory specs, again. The list can be pretty short, a valve job and a new set of rings, in some cases, not even that.

So in the end, it doesn't sound like we know what level of rebuild was done to your engine. It may be possible the crankshaft and cam bearings were never replaced. It is hard to say without more data.

When you began your post suggesting you have a (I admit I presumed a blue-printed and FULLY rebuilt) engine, acting worn out after only 1000 miles, I think many of us are thinking about premature wear and an oiling issue.

Going from a not-smoking engine to a smoking one in 1000 miles does suggest something in there is worn. Any major oiling issues, or issues where little or no oil flow was occurring, may not even last 1000 miles. It's not a big deal, and I'm not trying to be critical of the OP, or their engine.

The advice I may give for a "blue printed" engine with 1000 miles on it, versus a "freshened-up" engine with (potentially) 200K miles on some of the internal wearing parts, is going to be different.

Unless you find something wrong with your oiling, you may have to live with the engine smoking and the wear. If and when you decide to have the engine "rebuilt" you may want to be clear about what you want.

If you never saw the oil light come on, while revving your engine in a burnout or flooring it up an on-ramp, chances are good you did NOT starve the engine for oil by running it dry. To make an engine wear out fast, requires running it hard and/or frequently with less oil (or old oil) than it needs.

Since new and/or different oil pumps have been changed and tried without much improvement. Without knowing bearing clearances or tearing it down to measure everything. How about a cracked pick-up tube.

. I’m pretty sure the pick up tube looked ok when I put it in, but anything is possible. How do you make sure the pick up tube is in the correct position anyway? If I remember correct , I may have tightened it slightly past level so when I put the pan on , it would push up and level the pick up(disk with screen)as the pan moved into place. Some people mentioned that” the pick up disk/screen could be too close to the bottom of the pan” . I don’t think that is possible because there is the half circle piece of metal at the bottom that keeps the pick up screen from resting fully against the pan bottom. Also another reason I personally don’t think the pickup position is causing my problem, is because I have low pressure at lower rpm’s such as at idle when more oil should be available in the pan for the tube to pick up. A crack in the pipe or possibly a leak at the end where the tube threads into the block could still be a cause.

 

[moparmike68]

. I’m pretty sure the pick up tube looked ok when I put it in, but anything is possible. How do you make sure the pick up tube is in the correct position anyway? If I remember correct , I may have tightened it slightly past level so when I put the pan on , it would push up and level the pick up(disk with screen)as the pan moved into place. Some people mentioned that” the pick up disk/screen could be too close to the bottom of the pan” . I don’t think that is possible because there is the half circle piece of metal at the bottom that keeps the pick up screen from resting fully against the pan bottom. Also another reason I personally don’t think the pickup position is causing my problem, is because I have low pressure at lower rpm’s such as at idle when more oil should be available in the pan for the tube to pick up. A crack in the pipe or possibly a leak at the end where the tube threads into the block could still be a cause.

Another thing I was just thinking about it related to the windage tray. The added thickness of the windage tray and the second gasket( 2 gaskets, one on each side of the tray would add about 3/8 to a1/4” . This added thickness would mean that the pickup screen would be 3/8- 1/4” higher off of the bottom of the pan. Don’t think that is enough distance to make much of a difference but what do y’all think?

 

[moparleo]

Factory Service Manual will tell you that the pickup should touch the bottom of the pan.
Was pickup screen replaced ? Tube leaks are possible and will affect volume and pressure.
Never assume that any thing that was not documented was done.
Shops will generally tell you every thing that they did so they can charge you for it accordingly.
I think we have all seen "rebuilt" engines that turn out to just be cleaned and painted on the outside.

 

[540HemiCuda]

Even IF the pick up was right on the bottom of the pan, it shouldn't impact the pressure at idle. Especially HOT idle where the oil would be thinner and actually easier to pass the restriction. And if it were so close as to restrict the flow at idle, there couldn't be very much, if any flow at RPM. The restriction would be enough that there would be noise and engine damage pretty quick.

And aeration can be an issue, but rarely. And again, I doubt it at idle.

I will suggest again to take the simplest routes; try heavier weight oil and then maybe a hi volume pump and see what the results are. They would at least give you more information on how the pressure reacts to those changes even if they didn't put the issue to bed.

If those changes don't work, get back to us and we'll take the next step which will depend on what those previous steps reveal.

Good luck.

.

 

[Former owner]

I agree with some of the above posts, but disagree with some of the opinions offered.

The OP's hot oil pressure is too low. He should address it.

If the OP does decide to go into the engine to investigate, he does not necessarily need to pull the engine. IF he decides to go that route, then the very first thing to do would be to pull the pan (that can be done with the engine in the car) and Plastigage the rod bearings. If they are on the wide side, oversize bearings USED to be available which would tighten up the clearances. All that can be done in the car. We have used Plastigage in many applications for decades and have found it to be very accurate as long as it is fresh and soft. I, personally ALWAYS Plastigage the rods as I assemble an engine just to be SURE they are where I want them to be.

But the OP said that he would prefer not to go that route. So, trying heavier weight oil and then, if needed, an HV pump have a very good chance of getting him where he needs to be. Which in my opinion and experience is around 15 pounds hot idle (somewhat depending on his idle speed) and about 60 pounds hot max, preferably by 3,500 or so. None of that is set in stone, just good bench marks to shoot for. Some more would not be a bad thing nor would slightly less. They are just ballparks.

.

I agree with this except to say that I would not limit checking clearances to rod bearings. By virtue of their larger size, the mains have an even larger potential to affect oil pressure. I had this exact same issue on a 318 a million years ago, and we traced it to a worn main bearing. When I sent the engine to the machine shop to start my rebuild, I was asked my preference for clearances (low/high limits). Low (tight) limits tend to yield maximum oil pressures, and high (loose) limits tend allow for freer revving, albeit at a lower oil pressure. And if it is a worn rod or main bearing, it will generally be obvious visually as soon as you open it up. The plastigage will help to confirm clearances.

 

[moparmike68]

Even IF the pick up was right on the bottom of the pan, it shouldn't impact the pressure at idle. Especially HOT idle where the oil would be thinner and actually easier to pass the restriction. And if it were so close as to restrict the flow at idle, there couldn't be very much, if any flow at RPM. The restriction would be enough that there would be noise and engine damage pretty quick.

And aeration can be an issue, but rarely. And again, I doubt it at idle.

I will suggest again to take the simplest routes; try heavier weight oil and then maybe a hi volume pump and see what the results are. They would at least give you more information on how the pressure reacts to those changes even if they didn't put the issue to bed.

If those changes don't work, get back to us and we'll take the next step which will depend on what those previous steps reveal.

Good luck.

.

Thanks a lot everyone for your kelp!

 

[Daves69]

Another thing I was just thinking about it related to the windage tray. The added thickness of the windage tray and the second gasket( 2 gaskets, one on each side of the tray would add about 3/8 to a1/4” . This added thickness would mean that the pickup screen would be 3/8- 1/4” higher off of the bottom of the pan. Don’t think that is enough distance to make much of a difference but what do y’all think?

This is a nonissue, IMO.
I run the 402 pan and windage tray as well in my '69 Barracuda. My long block has been together for many years and still has good oil pressure. Granted it's done more sitting than rolling around town. It still runs around 35 psi hot idle 800..ish RPM.

A still @ about 1K RPM warmed up (not its hottest)......

View attachment 150750
If you were pulling air into the oil, you should see evidence of it in the oil. Remember post 2 aerating question and your response?

Did you ever open up the oil filter?

BTW, I'm thinking you must be getting at least some oil to the rockers if hydraulic or they'd be clattering.

 

[moparmike68]

I agree with this except to say that I would not limit checking clearances to rod bearings. By virtue of their larger size, the mains have an even larger potential to affect oil pressure. I had this exact same issue on a 318 a million years ago, and we traced it to a worn main bearing. When I sent the engine to the machine shop to start my rebuild, I was asked my preference for clearances (low/high limits). Low (tight) limits tend to yield maximum oil pressures, and high (loose) limits tend allow for freer revving, albeit at a lower oil pressure. And if it is a worn rod or main bearing, it will generally be obvious visually as soon as you open it up. The plastigage will help to confirm clearances.

Thanks I wasn’t aware that you needed to “instruct the builder” on how to rebuild the engine ? Kind of crazy. If I knew everything about rebuilding an engine, I would just do it myself. I told the guy I wanted it rebuilt to stock specs. I didn’t say I wanted it “partially” rebuilt . I understand if you race cars and you might want to inject your wishes or wants regarding the build, but normal joe blow just wants his engine rebuilt to like new so that he can drive it and it be reliable.

 

[moparmike68]

This is a nonissue, IMO.
I run the 402 pan and windage tray as well in my '69 Barracuda. My long block has been together for many years and still has good oil pressure. Granted it's done more sitting than rolling around town. It still runs around 35 psi hot idle 800..ish RPM.

A still @ about 1K RPM warmed up (not its hottest)......
View attachment 150746
View attachment 150750
If you were pulling air into the oil, you should see evidence of it in the oil. Remember post 2 aerating question and your response?

Did you ever open up the oil filter?

BTW, I'm thinking you must be getting at least some oil to the rockers if hydraulic or they'd be clattering.


View attachment 150745

Yes I did open up the filter and the oil was dark, but I did not see evidence of bearing material or shiny metallic particles or residue. And no I have never noticed any ticking or other noises coming from the engine. I know what an engine that has low oil pressure( or low oil level) sounds like and Yhis engine never has made noise. Even when the oil pressure(ongauge) showed10psi or less.

 

[Former owner]

Thanks I wasn’t aware that you needed to “instruct the builder” on how to rebuild the engine ? Kind of crazy. If I knew everything about rebuilding an engine, I would just do it myself. I told the guy I wanted it rebuilt to stock specs. I didn’t say I wanted it “partially” rebuilt . I understand if you race cars and you might want to inject your wishes or wants regarding the build, but normal joe blow just wants his engine rebuilt to like new so that he can drive it and it be reliable.

Agreed...but you do have choices based on what you want the engine to be. For example, if he was thinking you were building a hot rod, he might tend to leave it on the loose side to facilitate free revving. If you told him bone stock, it should probably fall somewhere in the middle, with plenty of oil pressure at hot idle. My bet is on one or more worn crank bearings. Am very interested to hear what you discover. It's important to learn why the original engine failed, and make sure that is dealt with on rebuild.

 

[Ricks72Chlgr440]

Thanks I wasn’t aware that you needed to “instruct the builder” on how to rebuild the engine ? Kind of crazy. If I knew everything about rebuilding an engine, I would just do it myself. I told the guy I wanted it rebuilt to stock specs. I didn’t say I wanted it “partially” rebuilt . I understand if you race cars and you might want to inject your wishes or wants regarding the build, but normal joe blow just wants his engine rebuilt to like new so that he can drive it and it be reliable.

It is weird to have to tell a seasoned shop "how to build", but they often have younger inexperienced guys doing much of the work now. In my case, I trusted the local builder to assemble my stroker. They did just that, assemble. My bearing clearance must be quite large due to the low oil pressure. The old saying of "trust and verify" applies here. I trusted but did not verify. They built engines for us in the past that were excellent.