oil pressure fluctuations

Posted By: slickrock

oil pressure fluctuations - 03/05/15 11:14 PM

I have a 440 stroker in a 70 cuda that the oil pressure fluctuates in,i have tried an adjustable oil pressure regulator, and then a new melling oil pump, and different weights of oil. there seams to be no ryme or reason to it. Somedays everything is fine ,other days its good and then drops to close to 0 after reving for a while, when I go back to idle the pressure will slowly climb back up and then go back down when the engine revs again. anyone have any ideas? It has a stock oil pan.

Posted By: Paul_Fancsali

Re: oil pressure fluctuations - 03/05/15 11:16 PM

You are sucking the pan dry or foaming the oil Is this a high volume pump?

Posted By: slickrock

Re: oil pressure fluctuations - 03/05/15 11:18 PM

yes it is

Posted By: John_Kunkel

Re: oil pressure fluctuations - 03/05/15 11:21 PM

Factory gauge? What RPM when the pressure drops?

Posted By: JohnH

Re: oil pressure fluctuations - 03/05/15 11:24 PM

Did you put a windage pan over the oil pan? If not that could be your problem.. Remember a 440 is a dry sump engine, The wind off the crank could be causing the oil pump to cavitate and causing it to just pump air and oil..

Posted By: slickrock

Re: oil pressure fluctuations - 03/05/15 11:25 PM

factory gauge, I think it drops around 2500 or more. How many qts of oil should this engine take. I think its 493 cubic inches

Posted By: slickrock

Re: oil pressure fluctuations - 03/05/15 11:27 PM

I have never had the oil pan off< so I don't know about the tray

Posted By: JohnH

Re: oil pressure fluctuations - 03/05/15 11:29 PM

If there is not one there, very could be your problem,, the higher the RPM the more wind off the crank.. It's foaming the oil.. If there is one on there you will see the side of it,, along with 2 oil pan gaskets..

Posted By: slickrock

Re: oil pressure fluctuations - 03/05/15 11:37 PM

does anyone know how many qts of oil this engine takes?

Posted By: slickrock

Re: oil pressure fluctuations - 03/05/15 11:43 PM

I will take a look and see if I have a tray this weekend

Posted By: Pacnorthcuda

Re: oil pressure fluctuations - 03/05/15 11:43 PM

Quote:

Remember a 440 is a dry sump engine,

Umm, no its not.

Posted By: bboogieart

Re: oil pressure fluctuations - 03/05/15 11:47 PM

I like to check the simple things first.
Stock gauge or mechanical?
Have you tried a different gauge or sender unit?
Stock pan should hold 5 quarts of oil.
I always put in 6. 1 for the filter.

Posted By: slickrock

Re: oil pressure fluctuations - 03/05/15 11:56 PM

stock gauge, I have not checked anything with the gauge

Posted By: bboogieart

Re: oil pressure fluctuations - 03/06/15 12:03 AM

I'd make sure the gauge is working before digging into the motor.
Worth a shot, right?

Posted By: hemi71x

Re: oil pressure fluctuations - 03/06/15 12:05 AM

Quote:

I like to check the simple things first.
Stock gauge or mechanical?
Have you tried a different gauge or sender unit?
Stock pan should hold 5 quarts of oil.
I always put in 6. 1 for the filter.

Incorrect.
A stock pan holds 4 quarts of oil, and one for the filter.
Page 9-98 in the specifications section, of the 1970 factory service manual.

Posted By: burdar

Re: oil pressure fluctuations - 03/06/15 12:06 AM

Hook up a mechanical gauge to verify the pressure.

Posted By: slickrock

Re: oil pressure fluctuations - 03/06/15 12:07 AM

yes it is, Ill check all the suggestions and see what happens, Thanks

Posted By: Supercuda

Re: oil pressure fluctuations - 03/06/15 12:09 AM

Quote:

Hook up a mechanical gauge to verify the pressure.

Do this first.

Stock gauges are not real precise, or accurate and when a stock sending unit starts going bad I've seen your symptoms.

Posted By: 71birdJ68

Re: oil pressure fluctuations - 03/06/15 12:09 AM

Has any of the wiring from the sending unit to the harness been changed, or messed with? The resistance wire might be missing, that is if a 70 model had that feature.

Posted By: Supercuda

Re: oil pressure fluctuations - 03/06/15 12:14 AM

Quote:

Has any of the wiring from the sending unit to the harness been changed, or messed with? The resistance wire might be missing, that is if a 70 model had that feature.

There are no resistance wires in a MoPar wiring harness.

Posted By: slickrock

Re: oil pressure fluctuations - 03/06/15 12:14 AM

don't know about the wiring, but ill try a stock guage

Posted By: RapidRobert

Re: oil pressure fluctuations - 03/06/15 12:17 AM

Quote:

. Somedays everything is fine ,other days its good and then drops to close to 0 after reving for a while, when I go back to idle the pressure will slowly climb back up and then go back down when the engine revs again.

(1) As said confirm true psi with a mech gauge (my guess bad elec gauge/sender) (2) toss in an extra 2 qts of oil on the chance the pickup is too far from the pan (not real likely but an easy check) & the extra slosh wont kill ya for a 1 day check. (3) if all good so far then the pan has to come off as zero psi (even briefly) ain't gonna cut it so you can dig in further but the ok/not ok makes me think elec gauge problem

Posted By: dart4forte

Re: oil pressure fluctuations - 03/06/15 12:17 AM

Don't rule out a possible crack in the pickup tube. They can crack from vibration.

Posted By: slickrock

Re: oil pressure fluctuations - 03/06/15 12:26 AM

extra oil and stock gauge are the first things ill try, hopefully one of those are the problem

Posted By: bboogieart

Re: oil pressure fluctuations - 03/06/15 12:37 AM

I'd hook up a cheap after market mechanical gauge, cause it would be the easiest and cheapest to do. Wouldn't even have to mount it, if you want to keep the dash stock. If it shows the same symptoms then no need to dig into the dash to replace the factory gauge.
I'm kinda leaning towards the pick up tube next. Loose or cracked.

Posted By: slickrock

Re: oil pressure fluctuations - 03/06/15 12:42 AM

sorry, I should have said aftermarket gauge, I knew what I was thinking , just not what I was saying

Posted By: bboogieart

Re: oil pressure fluctuations - 03/06/15 12:55 AM

Posted By: JohnH

Re: oil pressure fluctuations - 03/06/15 03:00 AM

Also, my 440 I put a "T" coming-out of the block for the oil pressure.I have the factory gage, and I also installed a direct pressure gage. The factory says 20 psi,, and the direct stays at 50psi.. But you do have two places to install oil pressure gages back there if you don't want to T it off, If you install a direct gage, which I recommend get copper tubing, don't use that plastic. I feel strongly there is no windage tray on that block,, but like every one is saying get a direct gage..

Posted By: Pacnorthcuda

Re: oil pressure fluctuations - 03/06/15 03:50 AM

Quote:

Also, my 440 I put a "T" coming-out of the block for the oil pressure.I have the factory gage, and I also installed a direct pressure gage. The factory says 20 psi,, and the direct stays at 50psi.. But you do have two places to install oil pressure gages back there if you don't want to T it off, If you install a direct gage, which I recommend get copper tubing, don't use that plastic. I feel strongly there is no windage tray on that block,, but like every one is saying get a direct gage..

What factory (Mopar 440 equipped) gauge has PSI readings on it???

Posted By: Sinitro

Re: oil pressure fluctuations - 03/06/15 05:43 AM

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Quote:

Also, my 440 I put a "T" coming-out of the block for the oil pressure.I have the factory gage, and I also installed a direct pressure gage. The factory says 20 psi,, and the direct stays at 50psi.. But you do have two places to install oil pressure gages back there if you don't want to T it off, If you install a direct gage, which I recommend get copper tubing, don't use that plastic. I feel strongly there is no windage tray on that block,, but like every one is saying get a direct gage..

What factory (Mopar 440 equipped) gauge has PSI readings on it???

My 70RR has PSI readings on the OE oil guage...

Just my $0.02...

Posted By: JohnH

Re: oil pressure fluctuations - 03/06/15 06:13 AM

Quote:

Quote:

Quote:

Also, my 440 I put a "T" coming-out of the block for the oil pressure.I have the factory gage, and I also installed a direct pressure gage. The factory says 20 psi,, and the direct stays at 50psi.. But you do have two places to install oil pressure gages back there if you don't want to T it off, If you install a direct gage, which I recommend get copper tubing, don't use that plastic. I feel strongly there is no windage tray on that block,, but like every one is saying get a direct gage..

What factory (Mopar 440 equipped) gauge has PSI readings on it???

My 70RR has PSI readings on the OE oil guage... My 69 Charger has PSI

Just my $0.02...

Posted By: JohnH

Re: oil pressure fluctuations - 03/06/15 06:14 AM

Quote:

Quote:

Remember a 440 is a dry sump engine,

Umm, no its not.

Ummm yes it is..

Posted By: 71birdJ68

Re: oil pressure fluctuations - 03/06/15 07:14 AM

Quote:

Quote:

Has any of the wiring from the sending unit to the harness been changed, or messed with? The resistance wire might be missing, that is if a 70 model had that feature.

There are no resistance wires in a MoPar wiring harness.

My 71 has it, and it is in the wiring diagram in the service manual. Look at the 71 Hemi engine wiring diagram.

Posted By: Cab_Burge

Re: oil pressure fluctuations - 03/06/15 08:40 AM

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Quote:

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Remember a 440 is a dry sump engine,

Umm, no its not.

Ummm yes it is..

Dude, do you know what a dry sump oil system is or looks like? Evindently you think you do

Evidently your wrong

Google it and look at it carefully and then let us know what you find out

FWIW a dry sump oil system does not store or use any of the oil caught in the oil pan for pressure, the dry sump oil pump sucks all the oil out of the oil pan and blows it into a storage tank( through indidvidual exteranl oil lines) that has oil and air seperators in it and then allows the oil to be suck down into the oil pump through another hose and the pump pumps it back into the motor through another external oil line

The initial cost on a decent dry sump system starts around $3000.00 the last I heard

Not something commonly found on mass produced automotive engines

Posted By: Cab_Burge

Re: oil pressure fluctuations - 03/06/15 09:04 AM

It sounds like it is time for you to find out exactly how much oil is in your engine now and how much it should have. Drain the oil with the motor hot or at least warm and measure it, write it down and then look at the oil pan and see if it has any numbers stamped into or on the oil pan anywhere

If it does let us know those numbers, Mopar had two different stock oil pans on the BB and Hemi motors in 1970 and 1971

The common production "402' oil pan and the 1970/71 only 426 street hemi and 440 6 pak oil pan

If you oil pan doesn't have any numbers stamp into it measure the depth of it at the back of the sump where the oil drain plug is, measure from the engine block down to the bottom of the oil pan and the length and width of the center oil sump and let us know those measurements

The common misconception on the proper amount of oil in the stock 402 oil pans originates from factory service manuals that said 4 quarts, they had the wrong amount in them

It show 4 quarts plus one for the oil filter, Mopar sent out several diffeent service bulletins over the years correcting that to be 5 quarts plus one for the oil filter

the 1970/1971 426 street Hemi and 440- 6 pak oil pans hold 6 quarts plus one for the oil filter, that is the best stock oil pan to use in any 1966 to 1971 B and E body with a B or RB or Street Hemi motor in those cars

You need the matching oil pick up also to use those pans correctly to prevent oil starvation.Let us know what you find out, I always add the proper amount of oil to the motors I build and then make sure the oil dipstick is showing full with the correct amount of oil in them, if not reading correctly I correct and calibrate the dipstick so it reads correctly

I learned a very hard lesson years ago on a car I took in trade, the Mopar chrome dipstick showed the motor to be around a half a quart over full when it only had two and half quarts of oil in the oil pan

I ended up spinning a rod bearing in that motor due to oil starvation

I now drain and verify all the motors I take in that I didn't build to start with

No matter who built them, verify, verify and reverify to make sure you know exactly what you have

IHTHs

Posted By: Dabee

Re: oil pressure fluctuations - 03/06/15 05:08 PM

Listen to what Cab is saying. He's is 100% right one. One other thing on the question of how much oil the pan holds. He said its a stroked 440, I betting he has an aftermarket pan on that engine. Most likely an 8 quart pan.

Posted By: dynorad

Re: oil pressure fluctuations - 03/06/15 06:48 PM

When the oil pressure says "0" are your rods knocking? If not that would point to incorrect pressure gauge.

Posted By: BSB67

Re: oil pressure fluctuations - 03/06/15 08:12 PM

Quote:

When the oil pressure says "0" are your rods knocking? If not that would point to incorrect pressure gauge.

if it has hydraulic lifters you would think those would be clattering pretty good....

Posted By: slickrock

Re: oil pressure fluctuations - 03/06/15 09:12 PM

I do not hear any knocking, no noticeable change in engine sounds

Posted By: RapidRobert

Re: oil pressure fluctuations - 03/07/15 02:11 AM

Quote:

Quote:

When the oil pressure says "0" are your rods knocking? If not that would point to incorrect pressure gauge.

if it has hydraulic lifters you would think those would be clattering pretty good....

Exactly! Ding ding ding I do believe we have a winna. they would be clattering for sure & further points to a faulty gauge/sender rather than actual psi

Posted By: 71birdJ68

Re: oil pressure fluctuations - 03/07/15 02:31 AM

Quote:

Quote:

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Has any of the wiring from the sending unit to the harness been changed, or messed with? The resistance wire might be missing, that is if a 70 model had that feature.

There are no resistance wires in a MoPar wiring harness.

My 71 has it, and it is in the wiring diagram in the service manual. Look at the 71 Hemi engine wiring diagram.

I asked Frank Badalson about this resistance wire I was talking about, and he said all 70-71s with rally gauges have this wire to insure proper pressure indicating system operation. So, there.

Posted By: Supercuda

Re: oil pressure fluctuations - 03/07/15 02:43 AM

Quote:

Quote:

Quote:

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Has any of the wiring from the sending unit to the harness been changed, or messed with? The resistance wire might be missing, that is if a 70 model had that feature.

There are no resistance wires in a MoPar wiring harness.

My 71 has it, and it is in the wiring diagram in the service manual. Look at the 71 Hemi engine wiring diagram.

I asked Frank Badalson about this resistance wire I was talking about, and he said all 70-71s with rally gauges have this wire to insure proper pressure indicating system operation. So, there.

I asked Donald Duck and he said Frank who? So there.

I only have the 71 body FSM, so there are no engine compartment diagrams available to me. My 70 FSM does not show this wire, nor does my 72. And yes, I looked at the rallye cluster diagrams.

Posted By: 71birdJ68

Re: oil pressure fluctuations - 03/07/15 03:03 AM

In the 71 Plymouth, Chrysler FSM it is in the Hemi engine wiring diagram page 8-157 Fig 13. where it shows the sending unit, and it is a separate wire that can get lost. Frank is Roger Gibsons partner, and they do some of the most accurate restorations around, and they also sell some of the most accrete repro parts there is. They sell this resistance wire. The gage can fluctuate without it. That's why I asked the OP if it was missing. And everybody knows Donald Duck is a ferry, and that Daffy Duck more of a mans duck.

Posted By: JohnH

Re: oil pressure fluctuations - 03/07/15 06:49 AM

You are using the sending unit that looks like a bell? Your not using the sending unit for a light? I hope I didn't insult your knowledge on this matter.. But just a thought..

Posted By: Supercuda

Re: oil pressure fluctuations - 03/07/15 06:53 PM

Quote:

In the 71 Plymouth, Chrysler FSM it is in the Hemi engine wiring diagram page 8-157 Fig 13. where it shows the sending unit, and it is a separate wire that can get lost. Frank is Roger Gibsons partner, and they do some of the most accurate restorations around, and they also sell some of the most accrete repro parts there is. They sell this resistance wire. The gage can fluctuate without it. That's why I asked the OP if it was missing. And everybody knows Donald Duck is a ferry, and that Daffy Duck more of a mans duck.

440 stroker in a 70 Cuda

Not a Hemi in a 71.

Still no wire though.

Posted By: 71birdJ68

Re: oil pressure fluctuations - 03/08/15 01:07 AM

Like I said 70, and 71 with rally gauges is supposed to have the wire. My car is a 383 car, and it has the wire. I don't know what your problem is, I'm just trying to point one thing out to the OP that he can very easily ck, and you have some kind of problem with that. As far as most people on here know, Frank, and Roger are nationally known Mopar experts, which it appears you're not. Try to help the OP instead of being a Richard Cranium.