I lost oil pressure on my 451. I was doing about 50 MPH @ 2900 RPM and the pressure just started falling. Oil level was checked SAT. I pulled the oil pump and the rotor and housing looks good, 1 question is how much slop should there be in the oil pump drive. To me there seems to be a lot of slop in the drive. If I don't find something, I guess I am into pulling the engine.

 

have you checked out your lifters?

 

Stuck lifter... bent push rod... push rod popped out of the lifter...

A place to start would to be to pull the rockers off and check all the push rods and lifters.

 

I would say the place to start is check the gage, sending unit, wiring etc before pulling rockers etc. Just my 2 cents

 

yep i agree start with the gauge past experience tells me it could save you alot of work you dont need to do

 

I think I would look at the gauge and wiring as well, especially if I was not experiencing any other abnormalities.

My Dodge 340 idling cold shows about 60 lbs. Idling warm around 15 lbs. What would be good oil pressure for this motor?

 

Agree with barfly to polaradude.
Pretty sure if you had a stuck lifter or bent push rod, your engine would run like crap. (missing, chugging or making a gawd awful noise.)

You didn't say if the gauge was stock or if it was an aftermarket that reads actual PSI.

Always go for the simplest things first.

There should be some slop in the drive gear but, not excessive.
Not knowing the age of the oil pump/drive makes it a little hard to guess.

You could unplug your coil wire. Disconnect the oil line to the guage and using a empty water bottle as catcher, turn your engine over. If oil comes spirting out, your pump is working. If it doesn't flow oil, follow the tube to the engine and remove it there. Try again and if no oil, your pump is bad or your pick up tube/strainer could be clogged. If there is oil, there, it could be a hole in your engine to gauge tube. Got to be going somewhere. If you have pressure, I'd try a new or different pressure gauge.
That is if this a aftermarket pressure gauge that reads PSI

If it's a stock sending unit type, remove the unit and turn the engine over a few times. Does oil come out there? If not. Again it could be a clogged pick up tube, strainer or the pump is bad. If it does come spirting out, change the sending unit.
Also check the wire connector going to the unit. If the inside connector isn't clean, it won't read right.

You could remove your distributor, take one of the valve covers off and then use a oil priming rod (don't we all have one?) and a drill to drive the oil pump. Then check to see if oil is making it up to your heads without running the engine.
Gotta take the drive gear out though to do this..

I hope it's simple man.

Good luck!

Mopar_71

 

15 lbs at idle is good
what is the pressure on the highway?

 

Very glad to hear that
Warm on the highway around 25 I believe if I am remembering right.
I'll be sure to look tomorrow.
Thank you, that is good news.

 

25 when the car is warmed up on the highway is also good
remember, you want 10 lbs for every 1000 rpm

 

yep, 25-30 it is on the highway.
Thank you.

 

exactly!

 

Well, today is the day to fire up the rebuilt motor. Looks like the smoking gun on this issue was the external oiling suppling the rocker shafts were flowing to much oil and starving the lower end. Motor was rebuilt with new bearings and I restricted the oil flow to the rockers to avoid repeating. Wish me luck.

 

Good Luck!