Defective Oil Pump?

[jimbosride]

The Coronet has about 300 miles on it since the restoration. I think the oil pressure seams funny to me? It has a plumbed oil pressure gauge along
With the stock light. Engine was professional built and Dyno run before install with no issues that I know of. When I fire it up cold it seem like it take to long for the pressure to show up on the gauge and dash light?
Once it come up it runs 70+ pounds cold and 20 at idle when warm. When shifting the car the pressure drops fast then picks right back up? Is the fluctuation in the gauge normal when shifting?
The last mopars I had did not have gauges or this kind of engine. Also when running it hard(5000 RPM shift) the oil pressure drops to Zero but that maybe because I am not running a baffled oil pan or windage tray?

It has 6qt of oil in it and it looks to be a rebuilt stock pump. Think I should swap out the pump? ….Oil filter drain back? It has a Wix filter and also tried a fram… Thanks

 

[BearDodge67]

Normal.. my light goes off after about 3 seconds then the gauge starts showing pressure. Gotta remember, the oil sender is as far away from pump as possible, and it can take a bit to buld up displayed pressure. unlike modern pumps that have sending unit mount right on the output of the pump

As for the oil pressure drop whn accelerating, it could be the pickupis too far from the pan bottom, so not enough has returned to be returned to the system

 

[Darter6]

Your pressures sound normal. You didn't state what weight oil you are running.
Sounds like a stick car. Yes it may be oil slosh back and forth in the pan causing gauge fluctuation.
6 quart pan ? so 7 quarts total with filter ? They make a adjustable oil pump attachment for big blocks if it really bothers you.
Then you can dial in what you want. Most oil light sending units are between 2 to 5 psi for the light to go off.

 

[jimbosride]

Yes it is a stick car. Lucus 10/40 oil. Stock pan. Running 6 Qts with filter. The fluctuation is even when shifting normal? My concern is the cold start oil pressure delay ?

I think I can make a camera clip of a cold start.
I have heard of these adjustable oil pump springs. Is there a drain back issue with these big blocks that would cause slow cold oil pressure at start time?

Thanks

 

[beanhead]

Once it come up it runs 70+ pounds cold and 20 at idle when warm.

That's perfectly acceptable.

Also when running it hard(5000 RPM shift) the oil pressure drops to Zero but that maybe because I am not running a baffled oil pan or windage tray?

Dropping to 0psi at 5000rpm is NOT good...even if it's momentary. That means air is getting into the system. Definitely use a pan with a baffled sump. A windage tray is always a good idea but isn't intended to keep the pickup covered, which is the most important thing.

Cool looking Coronet by the way

 

[BSB67]

Your startup condition sounds normal.

Your hot oil pressure is probably acceptable. However, we cannot say that it is correct, good, or normal without considerably more info about the engine, the pump and operating conditions. With the info you gave, I can only say that your hot oil pressure of 20 psi may, or may not be okay.

Finally, zero oil pressure under driving conditions is not good even for a second. Again, with the info given, we cannot say for sure as to why, but as someone stated, you really need a pan with baffles.

 

[Fran Blacker]

Sucking air around threads of pickup? would be unusual.

 

[Daliant]

Put a windage tray and a baffled oil pan in that thing before you spin a bearing, sounds like you're driving the car in a fairly spirited manner and the oil is sloshing around in the pan uncovering the oil pump pickup momentarily, a gulp of air into the oil pump = no oil pressure.

 

[pnora]

The Coronet has about 300 miles on it since the restoration. I think the oil pressure seams funny to me? It has a plumbed oil pressure gauge along
With the stock light. Engine was professional built and Dyno run before install with no issues that I know of. When I fire it up cold it seem like it take to long for the pressure to show up on the gauge and dash light?
Once it come up it runs 70+ pounds cold and 20 at idle when warm. When shifting the car the pressure drops fast then picks right back up? Is the fluctuation in the gauge normal when shifting?
The last mopars I had did not have gauges or this kind of engine. Also when running it hard(5000 RPM shift) the oil pressure drops to Zero but that maybe because I am not running a baffled oil pan or windage tray?

It has 6qt of oil in it and it looks to be a rebuilt stock pump. Think I should swap out the pump? ….Oil filter drain back? It has a Wix filter and also tried a fram… Thanks

View attachment 1459647

View attachment 1459648

A professional engine build and a rebuilt stock pump do not seem right to me.

 

[dvw]

Oil pressure should never go to zero. It shouldn't drop off during a shift. Unless the shift is so slow the engine is returning to idle speed. I'd try adding a quart and see what happens. It sure sounds like the oil pick-up is sucking air. If it was mine and 1 more quart didn't eleiminate these problems the pan would be coming off for an inspection.
Doug

 

[jimbosride]

I think the baffle and or windage tray is going to be the answer if I plan on driving it hard. But at this stage I will just drive it normal until if / or when I decide to go forward with the pan work. Not sure what the builder put in for a pump.... need to look over the spec sheet .... Thanks everyone

Starting on another project ...

View attachment 1459768

 

[WileE]

If you have a plumbed mechanical oil pressure gauge, it should never go to zero. These prior posts pretty much says it.

 

[radical rob]

Regular oil pump is usually sufficient for engine. Get a different oil pan to keep the pickup covered as oil is sloshed to back of pan under accel.

 

[Geoff 2]

If it is an oversize oil pan, factory fill will not be enough.

 

[Kern Dog]

I've heard of oil pickup tubes with hairline cracks...that might be worth checking.
The stock shower-head looking end on the pickup should rest against the bottom of the pan.
Blue arrows show what should be against the bottom of the pan. Orange arrow shows the recess in the head to allow oil to flow into the pickup.

If the pickup is an inch off of the pan, you have about 1.5 quarts in the pan doing nothing.

 

[451Mopar]

Check that the "O"-ring is on the pump part that goes into the engine block. that is on the suction side, so if it is not sealing correctly the pump will try sucking air (or what ever is in the oil pump drive hole.)

 

[Dave6T4]

A high volume pump could momentarily evacuate a stock pan at high revs.

 

[Outsider]

I would want a baffled pan at least, and maybe check for a crack in the pickup. Never want to see 0 psi at 5k!

 

[Fran Blacker]

Driving and postponing a fix and driving could cost a lot.

 

[Orig69]

Try bleeding any air that might be in the plumbing going to the oil pressure gauge.