2006 gt oil pressure problem

[TBERNHARDT]

I have a 2006 gt that I just rebuilt the motor on. It has all new bearings, oil pump, hot rod cams, timing, new sending unit, ect. As well as a bore 20over. I put a mechanical guage tied in with the sending unit when i first got a low oil pressure light. When coming to a stop my oil pressure will drop to about 10-12 and under load idle at about 13-15. Now, it will only do this when the motor is hot. I am also currently running 10w30.

Prior to building the motor, I also had the low oil warning, but didn't hook up a mechanical guage then. I had the machine shop go through the heads and block as well.

Im currently at a loss because I cannot seem to make sense of why there is a loss of oil pressure only with those specific parameters. Any advice would be greatly appreciated.

The photos attached show oil pressure in park then in drive at idle.

 

[Juice]

If you had an oil pressure problem before the build: your rebuild didnt address the issue. Loss of hot oil pressure usually means too large bearing clearence.

 

[lwarrior1016]

Too large of bearing clearance, not enough oil pump, or too thin of oil.

What are your bearing specs? What oil pump did you install?

What does the pressure go up to when driving? What is the cold start pressure?

 

[GriffX]

And, where can you attach the pressure sensor?

 

[Dino Dino Bambino]

Loss of hot oil pressure usually means too large bearing clearence.

This.
By comparison, a weak oil pump will not only produce a low oil pressure at hot idle but also a lower than normal oil pressure at higher rpm. These engines should be generating 75psi at 2000rpm (hot) with Ford spec 5W-20.

 

[StockishS197]

When I checked mine a while back through the sending unit port, I had 30 PSI at hot idle at 850 RPM and would go above 60 PSI when increasing RPM to 2-3k. With 5w30.

If you just rebuilt, I would second looking over your bearing clearance.

 

[Midlife Crises]

Like others have said. You can loose oil pressure through bearing clearance. This includes the cam bearings in the heads. The cam phasers can leak oil. The cam drive chain tensioners can leak oil and the oil pump itself can loose a lot of oil pressure when worn. There are more than one oil pump available for these engines and I am a fan of the hi volume pumps due in part because of the variable cam timing system.

 

[Badd GT]

You have galley plugs on front and rear of block that should be removed to clean oil passages when block is rebuilt. Make sure the galley plugs were re-installed and tightened properly

 

[Laga]

I had my 4.6 rebuilt a couple of years ago with forged rods and pistons. The oil pump is a Melling high volume.
At a cold start, it has 95 psi @ 1200 rpm. At hot idle, 225°F & 650 rpm, the AEM digital gauge shows 10 psi using Amsoil Dominator 5W-20 racing oil.
As rpm’s go up, pressure averages 20 pounds per 1000 rpm with a max around 90-95 psi.
E-Force SC, 11# boost, E85.