2003 4.6 Oil Pressure Problem

[mikesjtbird]

I am writting this in hopes someone could shed some light on me with a problem I am having.
I installed a 2003 Mustang motor in my 97 T-Bird. Everyting was pretty straight forward on this swap. However, when the motor warms up I get a very noticeable valve rap and when in gear at idle the oil pressure light comes on. I am using 5w-20 as recommeneded and motor has 60,000 miles on it.
I bought a mechanical guage and hooked it up to the drain plug next to the oil filter.
600 rpm - no reading
1500 rpm - 7 psi
2000 rpm - 12 psi
2600 rpm - 26 psi
4000 rpm - 37psi
Redline - 50psi
These readings were takin in Neutral. I am thinking that I have a bad pump. The guy who sold the motor to me thought the throwout bearing was the culprit to this valvetrain noise. I am thinking there was more than one problem now.
-Mike-

 

[Mustang5L5]

Something is wrong with the motor. Those numbers are way too low. I don't think it's a bad pump though because the numbers do increase with RPM

 

[XtorT'r]

Wonder if you have some blockage in the oiling system.

 

[the98stang]

Yea you should have like 75 psi on start up (cold engine). then as she warms up 25-35 psi @ idle is normal. Is it still making a rattling noise from the bottom end? Did you do a compression test?

 

[mikesjtbird]

When I made the conversion I had to use the T-bird oil pan. I did inspect the bottom-end and top-end of the Mustang motor. From what I remember this motor was very clean with no visible varnish or sludge. After I noticed there was a valve rap, I did run engine flush through the motor. Did not do a compression test because to me the motor runs great, smooth idol, plenty of power, no oil burning or leaks. I did start her up today and the oil pressure went to 50psi at fast idol then dropped to 15psi. It almost seems like there is a defect or problem with the oil pump to where it works but only at 60% of what should be normal.
When the motor gets warms you can hear the cam followers tapping on both heads. A friend of mine said these need a minimum amount of pressure to keep them quiet. My first guess was a valvetrain problem but with low oil pressure I am thinking not.
If there was an oil blockage I would think the oil pressure would be high?

Thanks for you input and help guys.

 

[BobHyatt]

are you certain your oil pump pickup works with the oil pan you are using? If it touches the pan, it can starve the pump for oil. If it is bent or too far from the bottom, same problem. It is also possible there was interference and when you bolted the pan up, you introduced a leak where the pickup enters the pump, or somewhere in between there and the bottom of the pickup.

 

[mikesjtbird]

I used the pickup out of the T-bird motor. It is different because of the oil pan configuration. I am hoping that I can lift the motor enough to slide the pan out to inspect and service the pick-up and pump. Pulling the motor back out would be a lot of work.