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Over the summer i put a high volume oil pump in my 68 Galaxie. She would not pump oil for the life of me. I dropped the pan several times suspecting the impeller shaft was not secure. She still wouldn't pump. I gave up and put the original pump back in there. I also installed some aftermarket gauges to monitor my exact oil pressure. She pumped fine. Took her to a shop to get her timed this week and they said that she wasn't holding oil pressure. They recommended I run a 50 weight oil. I drove it around town for myself to see if there were any problems. My gauge read fine and the factory oil light wasn't on. I took her to the exhaust shop to throw some glass packs on it, because it had been open headers before then. Afterwards took it back to the same shop to get the carb tuned. Drove it home today, and the oil pressure was fine. Parked it, ran inside to grab a few things, then drove to the parts store to grab some parts for my everyday driver. As I was pulling in, I noticed my gauge read zero psi, and the factory oil light was on. I got what I needed then went straight home, with the no oil pressure still. There are no leaks anywhere from what I can tell, and the oil is full and clean. I am at a loss of ideas. I wanna figure this out once and for all. Any suggestions or advice would be mighty appreciated.

-Dave
 

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I noticed my gauge read zero psi, and the factory oil light was on.
Electric or mechanical gauge? Do you have a test gauge to verify pressure (or lack there of)?

What engine? Did you hear tappet noise when it showed low pressure?

It is a good idea to pack a new pump with either chassis grease or Vaseline to prime a new pump (or spin/prime it with a drill).
 

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It is a mechanical gauge. I don't have another gauge to verify. It seems like it does fine until it warms up. I didn't hear any noise when the pressure was low. If I end up throwing another pump in it, I'll be sure to pack and prime it.
 

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It is a mechanical gauge. I don't have another gauge to verify. It seems like it does fine until it warms up. I didn't hear any noise when the pressure was low. If I end up throwing another pump in it, I'll be sure to pack and prime it.
I wasn't going to chime in until the engine builders did, but did you not prime the pump? Did you wire the pressure gauge in series or in parallel with the the dummy light?
 

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I read your whole story -just wondering if you had any o.p. as you drove home, ie; at cruise rpm? If you did, but it went back to zero at stops and traffic lights, is there a chance the idle rpm has changed, due to lack of dashpot/idle solenoid causing throttle shaft to return to a lower position sporadically? A 100 rpm variance could make a difference, depending on how much engine wear has occurred.

When you changed out the pump, was the strainer full of plastic bits (timing gear teeth) ....is the pan pretty devoid of 'debris'? The oil pump & strainer are basically a wet shop vac, anything solid in the pan is eventually going to wind up in the strainer.

Another quick thought is what brand oil filter you running? ...when was it last replaced?

I have more ideas ...let's start there first.

Norm

..... I got what I needed then went straight home, with the no oil pressure still. There are no leaks anywhere from what I can tell, and the oil is full and clean. I am at a loss of ideas. I wanna figure this out once and for all. Any suggestions or advice would be mighty appreciated.

-Dave
 

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how many miles on engine... ????
what is the pressure reading cold..???
has any other work/modifications been done to motor...

like .. valve, roller rockers ....etc......
could have excessive bleed of ,thru rockers....that can be cured with restrictor plugs/jets...
worn cam bearings , worn crank/connecting rod bearings.. that will require a complete tear down ....

what made you decide to change the oil pump the first time.....low oil pressure..??
 

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You are going to have to beg, borrow and/or steal a quality mechanical gauge and drive the car to verify pressure. Usually, this scenario reveals a bad pump (and/or blocked screen) or excessive bearing wear. Using 50W will not cure the problem and most likely will only cause further wear.
 

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Recruit,
Just for ****'s and giggles have you pulled the valve covers to see if the oil is draining back into the engine. If you've got good oil pressure starting out and then don't have any after you drive it awhile, that might be worth looking at. Especially if your running gear grease (50W) oil. Rear end grease is 80W. Think about it.
Raggaren's post is right on. What have you had done to the motor. Oil pumps aren't the reason you normally have low oil pressure.
I drove a newly rebuilt 390 4000 miles when I started having oil pressure problems. When we tore it down we found the crank had been ground on a taper (all journals). They set it up in the lath crooked. That problem was because I didn't check the machinist work correctly and it wiped out half of the bearing on every journal. 50W oil will do more harm to your engine than good.
 

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What is the background on the engine?

Regardless, you need to verify the gauge, preferably with one that can show you single digit pressure to find out what is going on.

Once you do that, you will either have or have not :)

If you have no oil pressure, or very low:

If its a rebuild, there is a galley plug in the distributor hole on an FE that is often left out, it will dump pressure. There are also galley plugs in the lifter valley, however, the typical one forgotten is the one in the distributor bore accessed by taking off the timing cover

If its an old motor, you probably need a rebuild and no pump you put in there will overcome very loose clearance at the cam bushings and main bearings, and to a lesser extent rod bearings.
 

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I bought the car with 48k original miles on it. Original engine: 390FE 2bbl. I swapped out the intake for an Edelbrock Performer RPM 4bbl, then put a 625 street demon carb on it. Put Hooker long tube headers on it. And thats about all I have done to the engine, apart from chasing down this oil pump nightmare.

I was led to the pump problem first by investigating an oil pan leak. I dropped the pan, pump, and screen. As a matter of fact, I did have some "oil pan surprise" in the bottom and on the pump screen. Nylon/plastic pieces of the casing around the timing gear. I was told by a bunch of old hot rodders where I work that it wouldn't hurt anything, just clean it all out very well. So I did just that. Then when i threw the thing back together, it wouldn't pump oil, and I believe that it was because i didn't put the impeller shaft in there securely. I only knew it wasn't pumping because the factory oil light was on and I pulled off the new oil filter to find it to be as dry as it was when it came out of the box (THIS WAS BEFORE I installed the gauges.) I only run Wix filters because I've been told they're some of the best on the market.

To be sure it didn't happen again, I decided to install the gauges. The original oil sensor/sending unit threads right into the top of the oil filter adapter. I was told and read that placing a street T pipe into the oil filter adapter would allow me to operate off the factory dummy light system and add the oil pressure pipe fittings. So I did just that. I will post a picture of my setup tomorrow to make sure it looks Kosher.

I did put a cheap pair of chrome valve covers on there and have yet to investigate the drain back on them. I don't think they'd be doing any harm. They were engine specific and all.

On my ride around, while it is still cold, my gauges reads just over 25psi. Which, I have read is about normal/to be expected. I have not seen it physically "drop" on the gauge. I just look over an it is hovering right above zero. When I rev the engine, it acts like it ttys to go up a hair. But never all the way to the "1psi" mark.

Forgive me for trying to answer all these questions at once. Thanks already for the helpful advice and ideas.

I may pull the timing cover to investigate that distributor plug, but I'll be looking back here for further thoughts from the new info before I mess around with that.

-Dave
 

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On my ride around, while it is still cold, my gauges reads just over 25psi. Which, I have read is about normal/to be expected. I have not seen it physically "drop" on the gauge. I just look over an it is hovering right above zero. When I rev the engine, it acts like it ttys to go up a hair. But never all the way to the "1psi" mark.
If the gauge you bought is to be believed (most likely CHI-COM JUNK) your cold oil pressure should be much higher at cold temp. If you found debris (nylon coated cam drive gear/valve seals), you should have replaced both the pump and pickup. It is just a normal repair. Pumps do wear, especially when digesting nylon. The pickup screen will allow tiny amounts to pass it. It is a safety feature..

YOU HAVE TO VERIFY OIL PRESSURE WITH A QUALITY DIAGNOSTIC GUAGE before tearing into it.

As for drain-back, there are passages in the cylinder head(s) that allows oil to return to the pan. If these are blocked or there is too much volume on the top end, drain-back may be delayed enough as to where there is difficulty keeping the pump supplied. The pressure test will show this.
 

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Dave,
My opinion after what you've indicated is that the main bearings are gone. I say that because you have 25# of pressure when cold. You should have that at idle when hot. 65# oil pressure when cold is about normal. With only 48K miles on the car your car probably has a first run crank in it. Don't destroy it by making metal.
Also, if it comes to a bottom end overhaul, before you fire it up again, prime the oil system with a primer shaft on a 3/4" hand drill. Don't turn it on and let the engine do it while running. I've had my drill run for a least a minute before the pump started pumping. That's too long for bearings I'd think. Once metal is scuffed it's called a file. Best of luck man, I feel for you.
Jim
 

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I agree with both above

1 - Make sure you have a quality gauge and know what you are seeing. Idiot lights can have bad sending units and gauges can read incorrectly.

2 - Once you are comfortable that you actually have an oil pressure problem, it is doubtful that it is the galley plug if you have 25 when cold. As Jim said, mains are probably worn, but not just the mains, the cam bushings play a significant part in holding back oil pressure too, and rod bearings too but to a lesser extent. That being said, if the pan comes off easy enough, you can slip a set of mains (and even rod bearings) in to cheat a little if a rebuild isn't affordable right now. Sometimes it will tighten things up enough to get by.

Odds are its just a worn out motor, either its not really 48K miles, or when you ran it dry you gave the bearings a little beating

BTW just a comment, the oil pump drive shaft shouldn't be giving you problems. Just make sure you put it in from the bottom, so the clip is closer to the distributor than the pump. A technique is to slide the clip too far up, so that as you put the pump and shaft into the block, the block pushes the clip down. Then it cannot go anywhere, its held into the pump. When you go to prime that pump, the shaft turns and the clip moves to make just enough clearance so it doesn't wear but still won't fall out.

My guess is, you didn't have a pump drive problem though as much as an air bound pump, if you didn't do it before, start priming new pumps before fire up and then you'll know if you have oil pressure before starting the engine.
 

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i believe that if you had poured a little oil in the new HV oil pump and primed it , prior to initial start up... you would have been fine now....

I only knew it wasn't pumping because the factory oil light was on and I pulled off the new oil filter to find it to be as dry as it was when it came out of the box

-Dave
hate to say it ..time for a overhaul..
I believe bearings took a beating on initial dry run...
and driving it with close to zero oil pressure has done further damage ....

i would pull oil pan and a couple bearing caps to inspect..
see what bearings look like....


Here's what oil pressure looks like in my motor warm ...
cold it has 75-80psi...at idle on initial start up
it's a freshly rebuilt motor and has a HV oil pump.....


My Fe oil pressure - YouTube
 

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I never read the part about the oil filter being dry ( or didn't notice it ). On almost all FE's except for a few trucks, the oil filter is pointed straight down. I am able to put 3/4 qt. of oil in it BEFORE installing it. That way there's no time gap in supplying oil to bearings after oil and filter change. That red light scares me, and I'm not afraid of anything.
Also, google oil viscosities vs Temperatures. Hopefully you'll run across an article like I did that gave oil weights. and their approximate time to normalize oil pressure relating to temperature. That's why I won't use anything higher than 10W-30, especially during the winter. And, I'm pushing it then. But, until they make a 10W10 I'll have to make do.
The "10" = the weight of the oil at 214 degrees. The "W" = weather or 32 degrees. The last "10"= the weight of the oil at W or 32 degrees. It has been found that bearing will provide normal wear at a viscosity of 10 up to 214 degrees. Jim
 

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I would double check the oil return passages inside your valve covers. If they are clogged or do not flow properly a lot of oil will stay above the heads and not make it down to the sump so the oil pressure goes down. Just a thought. You haven't told us a lot about the engine. If old this is a possibility. Thicker oil will make this WORSE not better.
 
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