Alright so Driving home the other night the oil pressure gauge dropped and came back up a few times, paranoid I shut it down, went back to get the car with the trailer later. Noticed oil down the side of the car and found a cracked hose on my oil filter relocation, replaced the hose changed the filter and refilled with oil ( went from 15w40 rotella to 5w30 castrol edge since this is the 6th change since the engine was built back in July) Car built pressure so I drove it to the car wash to wash the oil off the side. Lost pressure again on the ride home. Trailered car home again ( yes it had oil in it still) swapped filter from the K&N to a motorcraft ( FL1A), grounded gauge and swapped the sending unit still no pressure. I pulled a feed line from one of the turbos and I have flow but it is weak, like a faucet that is barely on. Hoping to have time to pull it next weekend, there are no odd noises Anyone got any guesses as to what is going on????


4.6 mod motor stroked and bored to 5.0
SVO heads, and intake VT cams
Oil filter relocation done so I don't have to pull part of my hot side to change oil filters

 

did you use the billet oil pump when you built the motor?

 

yep melling billet pump and ATI dampner

 

You grounded the sending unit and it had no pressure still ? If you ground it, it should spike to the right. If it didn't that's a good sign for you it's not going to be mechanical, but electrical.

 

sorry grounded the guage and it worked, that is why i swapped the sending unit

 

Jesus, I hope its just the guage... seems like that motor is cursed for oil pressure!

 

if it was just the gauge the feed lines to the turbo would have more pressure from them

 

I hate to say this but when mine did the same thing it was the pump , put on a new punp and in 150 miles it started it again ended up being my thrust bearing was gone and letting the crank move foward and eating the pumps.

When i put the new pump on i used a Melling and it went out in 150 miles. I hope this is not your problem but its what mine did.

 

I have 2 cobra pumps at the house, I will check it once I get a chance to pull the motor

 

Did you try a mechanical gauge. It sounds like the pump , but I'd try a mechanical gauge before I pull the motor.

 

Did not try a Mech guage, but the fact the turbo feed is like a weak faucet it seems like a waste of time

 

did you replace both lines to oil filter relocator? maybe you swapped them and the oil filter has a check valve in it and it will stop the flow. can you easily get rid of relocator and put filter directly on engine to see if that is the prob.

 

Only swapped the one that split

 

Just jack the motor up a little and drop the pan and you can pull the rear cap and check the thrust bearing. I went through 2 pumps before i figured it out.

Here's my sad story. https://www.theturboforums.com/smf/index.php?topic=128136.0

 

anyway to look at a pump and tell if it is bad?? I have the engine out and the pump looks fine, I have about an 1/8 inch movement in the crank that my builder and I will be discussing in the next few days.

 

After your PM i thought i would show you the pump that came off it , its the Melling pump and it droped all pressure and this is all i could see wrong with it and the gears didn't have a mark on them. But the thrust surface of the crank was ate up, that why i said to replace the crank.

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One thing i did do after all of this was install a mach oil gauge so you can keep an eye on your pressure.

 

I will be putting a jumper on the back of the stock gauge to make it work like a gauge instead of an idiot light, by pump doesn't even have the marks yours does, I am too lazy to take a pick today but will tomorrow evening

 

dropped it off at my machinist today, having him check the crank, will probably go ahead and do bearings before I button it all back up

 

What block are you useing ? if you have a 1/8 thrust problem you are going to have to replace all the bearings. If you had 1/8 play in the crank the thrust face of the crank is most likely ate up if you let them machine it you will still have to much thrust movement in the crank even with new bearings. They told me they could build the thrust surface up on the crank by welding it and remachine it i told them no thanks, i didn't want a crank thats been welded on in a 800rwhp motor.