2002 Ford Explorer 4.0 SOHC Low Oil Pressure

[Cavalier3400Z]

Hi, I just rebuilt my 2002 ford explorer 4.0 SOHC engine at 180,000 miles. I replaced all the bearing, gaskets, oil pump, timing set. The main bearing clearances are .002, .002, .0015, .002. After the rebuild when hot oil pressure was dropping to 3psi at idle in gear. After replacing the pump with a ford one it drops down to around 9.5-10psi when hot in gear. This is around 650rpms. Last time I had this issue the front timing chain guide melted allowing oil to flow out the front galley but this is not the issue this time. At 1000rpms I have 25psi of oil and 45psi at 2000rpms. Any help would be greatly appreciated. I had the engine and trans out about 8 times trying to solve this issue. Also all the pistons and two rods are new too. I believe all the rod bearings measured .002.

Thank you for your time.

 

[Cavalier3400Z]

Anyone have any ideas?

 

[96firephoenix]

you didn't do a balance shaft delete, did you?

 

[08EddieCA]

4x4?

 

[Cavalier3400Z]

you didn't do a balance shaft delete, did you?

No, I didn't.

4x4?

yes, it is.

I have all the photos of assembly uploaded on my website in high resolution. It's my personal car and I've been trying to figure this out since February. I've had other friends who own garages look at it too. It's probably something stupid

http://dotterersautoservice.com/album/index.php?/category/61.

 

[Cavalier3400Z]

So, I tore the engine down and checked the bearing clearances again with plastigage. The only one I cannot check is the rear one since the trans is still installed.

Main:
#1 .0015
#2 .0015
#3 .0015

Rods front to back:
.002
.0015
.002
.0015
.002
.0015

 

[imp]

@Cavalier3400Z
Awright, bearing numbers good, in fact, Ford high-performance engines came with as much as 0.003" from the factory. So, where else can oil leak away in large amount? Pump, if worn out, you covered that. Camshaft bearings? Had quite a pronounced affect in the engines I worked on in the past, but not OHC, which should not be much different. Valve lifters and their bores in the block, excessive clearance? Or in the head if OHC, where they maintain zero valve lash). Pressure relief valve, is it built into the pump? Could it be faulty in the new pump?

Running out of ideas. Were any clearances other than bearings checked when eng. was out?

 

[Cavalier3400Z]

I have some leaking around he lash adjusters on the drivers side. I put air in the oil passages and you can see it bubble but does not seem like it would cause the issue. I only checked the bearing clearances on the crank.

 

[Gary Fraser]

Was this ever resolved ? I am going through the same thing right now

 

[Adam Robert]

Was this ever resolved ? I am going through the same thing right now

I too am going through this and would love to have any idea.
I just rebuilt my motor, replacing all the chains, cassettes, oil pump, and gaskets. Everything seems perfect, but my oil pressure is low. It’s about 5psi at idle and if I throttle it, it goes as high as 30.

 

[imp]

I too am going through this and would love to have any idea.
I just rebuilt my motor, replacing all the chains, cassettes, oil pump, and gaskets. Everything seems perfect, but my oil pressure is low. It’s about 5psi at idle and if I throttle it, it goes as high as 30.

We seem not to have considered camshaft bearings badly worn, bleeding away a lot of oil volume (and therefore pressure).