Oil Pressure Low

[oneof52]

Need a little help. About a week ago, I heard my rockers become a bit noisy. Recently rebuilt engine with Break In Oil was doing fine. Little over 400 miles thought I needed to change the in Oil. Changed the oil and filter, added 5W-30 Synthetic oil with an STP filter. Started the car and chatter became louder with near zero oil pressure. Thought it was the oil, changed to conventional with no luck. Shut the engine and put the car in the garage. Have been driving this car without any issues until now. Any suggestions will be appreciated.

70 Cuda
440 six pack
Miele HV pump installed when rebuilt

 

[Steve340]

I assume you checked oil pressure with a mechanical gauge - but if not the clattering is a clue.
Sounds like it needs to be pulled out and sent back to the rebuilder.

 

[oneof52]

Was working fine for 6 months, just recently it started

 

[Steve340]

You could check the oil pump relief valve is not stuck open.
Unfortunately low oil pressure is generally pretty much terminal.
Sorry to hear about this especially on a new engine.
Hope you have some good luck.

 

[EW1BH27]

Back in 2009 I did an oil/filter change and had next to no oil pressure right afterwards. I replaced the filter and pressure went back to what it always was.

Oddly, the no pressure filter was a Mopar one from my dealership. I had to wait for it, none in stock. My guess, it was an old one and deteriorated on the shelf, IDK. The “fixing” filter was a Fram, who’d a thought.

Not saying it’s the cure for you, just something that I experienced once.

 

[Steve340]

Definitely try another filter as in post #5.
Try all you can on the outside of the engine first.

 

[Daves69]

.................Changed the oil and filter,................

Maybe cut that filter open and see what it has filtered.

 

[Xcudame]

Since it's not a third generation Hemi, but a 440, I wouldn't anything thinner than 10w-30. And since 30w is still made, that's what I run in my 70 Challenger 383 with 250,000+ miles on the engine. Change the oil filter and hook up an actual mechanical pressure gauge and supply a result. Remember, oil only gets thinner as it ages! If you drain it and it's black, it's burnt that way!

 

[Challenger RTA]

Pull the distributor and spin the pump to see if you have oil. It's a good tattle tell.

 

[rickseeman]

I think you've ran it enough. From here I think you should diagnose by turning the oil pump with a priming tool and a 3/8" reversible drill.
Things that can cause your oil pump to suck air.
A damaged gasket between the oil pump and the block.
A damaged o-ring on the stub shaft that fits into the block.
A piece of trash holding the oil pressure relief valve off of it’s seat.
A crack in the pickup tube.
Remove the distributor and oil drive try to prime the oil pump to see if you can get pressure. Do you still have your old oil pump from before the rebuild?

 

[oneof52]

Here is how I began to notice...... I have has Lucas Break in Oil for about 300 miles, ran fine. Then last week I started hearing light chatter on the lifters and the rockers. Yesterday decided it was time to change the oil. Got 5W-30 Synthetic Oil from Costco and another for Amsoil, On the inlet of the oil filter, I have an adapter that has 2 hoses going to an external, oil cooler. Drained the old oil, replaced the oil filter and added the 5W-30 Synthetic. Oil pressure never came up and engine started running rough. Shut it down. Put back the old oil filter, and still no improvement. Changed the oil to Pennzoil 10-30 Conventional still no pressure. At this point, I am thinking it is the pump. Checked with the re-builder and he said he never replaced the pump.

My thought is the pump was going and took an oil change with Synthetic to accelerate the death.

My next steps are as follows;

1- Remove the oil cooler adapter
2- Replace the pump with a Meile High Pressure pump
3- Change the oil with 10W-30 Conventional
4- Put a Fram (Orange) PH-8A filter and then check

The amount of money is not worth risking the engine. My total cost is about $250

Thoughts?

 

[oneof52]

Sorry, Melling pump

 

[rickseeman]

That sounds good. Use the high volume pump instead. Melling M-63HV. These engines are old and have more clearance than they did 50 years ago. The high pressure pump is just a stock pump with a Hemi spring in it. It doesn't pump more oil. With todays clearances they sometimes won't give you enough oil pressure at hot idle and then people get all frowny faced. I don't think there is anything wrong with your old pump but that can be determined at a later date. For now I'm thinking the HV pump will get you going. Be careful putting it on. Take your time. It's hard to keep that gasket straight when you are putting the pump on in the car. It keeps trying to fall out. Don't force anything.

 

[sixpactogo]

Since it's not a third generation Hemi, but a 440, I wouldn't anything thinner than 10w-30. And since 30w is still made, that's what I run in my 70 Challenger 383 with 250,000+ miles on the engine. Change the oil filter and hook up an actual mechanical pressure gauge and supply a result. Remember, oil only gets thinner as it ages! If you drain it and it's black, it's burnt that way!

I have to disagree with the last part of your comment. If the oil is black, it is dirty not burnt. I've always been told "Oil never breaks down. It get dirty and contaminated."

 

[Challenger RTA]

Put a Fram (Orange) PH-8A filter and then check

That was a cause of death to one of my motors. I would rather have dirty oil then no oil!

 

[Chryco Psycho]

I disagree with a high volume pump , if you are using a stock oil pan stay with stock volume , I have seen the oil pan empty & pressure drop to zero on high RPM pulls for more than a few seconds

 

[Adam]

Only a couple of things could cause zero oil pressure all of a sudden. I would mark the edge of the distributor and pull it out, followed by the cam gear/oil pump shaft to see if it’s broken, thus no oil pressure.

And have you pulled the valve covers? I would look for a bent/broken pushrod and maybe a lifter that popped out of the lifter bore. That would give you no oil pressure. You can see into the lifter galley with a good flashlight. This exact thing happened on my 440.

 

[Xcudame]

Oil is getting black because gasoline and combustion debris are getting into it and as oil ages it breaks down and gets thinner. The combustion debris can make it thicker as setting for years, but the oil itself only gets thinner. Oil should be changed while it's still brown!

Every time, and I mean every time, I've ever rebuilt or reconditioned an engine, I replaced the oil pump with a new one! That's something my dad taught me and I'll never forget. $100 to $150 for a new Melling oil pump is like a penny saved is a penny earned. And I'd never rebuild a big block with anything less than a 6 quart hemi pan now that 440 Source sells them so cheap.

 

[oneof52]

Ok, so my next steps are the following;
1- Remove the oil cooler and put a fresh filter on the actual pump
2- Remove the distributor and the cam gear and prime the pump to see if oil is coming up
If Oil is coming up, then not the pump and possibly the external cooler clogged
If Oil oil is not coming up, then drain the oil and use a video probe to see if by chance the pick up is still in place. If it is in place, then its the pump.

I am hoping its the oil cooler and I can plug it and or remove it.

Will update when completed.

 

[Adam]

I would do #2 first, I think it’s the most likely problem and may save you some work.
I believe the pick up threads into the block, no way for it to fall out. It could be clogged with some type of debris though, like from a failed filter or vandalism. Id also cut open the old filter to see if there is anything unusual going on inside it.

And if you still have no pressure, don’t forget to pull a valve cover and look at the lifters.

Here is a link to my post re: no oil pressure. Broken pushrod