Low Oil Pressure Part 2

So boys I didn't wanna make this post but this engine has got me baffled beyond baffled. First off let me go into details on the engine. I started the motor for the first time couple weeks ago and had low oil pressure. Immediately pulled it and replaced some things.

All clearances are in spec, rotating assembly balanced and everything in the bottom end has been triple checked.

There is only one plug that ford doesn't supply in the block and that is the one behind the water pump which was plugged by us properly (the second time I pulled it) with a 17mm plug. We started with a 16.66mm plug and then decided we got the 17mm plug why not double plug if it'll fit. Sure enough the 17mm plug fit and was extremely tight over the 16.66mm plug. So the plug that goes behind the water pump has been for sure plugged.

The new oil pump I warrantied for another new pump

Replaced the o ring in the oil pick up and cleaned the pick up

replaced the oil pressure switch

Now basically the 4 things I could ever think of it being have been replaced. We put an oil pressure gauge on it and cold started it and it shot to 60psi then teetered off to 40...30.... then to 20... then I didn't want to risk it once it dropped below that as she warmed up. Thinking we might possibly have a faulty gauge we put back in the oil pressure switch and sure as shit she popped up low oil pressure once again. No oil leaking anywhere externally.

Now I am at a complete loss. I am about to pull the motor for a third time, which isn't the end of the world, but I can say I am pretty damn tired about it. Going to put ARP hardware in the bottom end and do a couple other things while I am there, but if I can't get this low oil pressure thing figured out I don't know if I am going to even have oil pressure after stripping the block back down to bare and having everything checked for the second time after being built originally.

Only thing I could possibly think is some how the cam phaser seals to the cam sprockets because those have oil pressure on them for the VCT? I inspected them like the book says to do and everything checked out and went back together smooth as silk, but I will replace them anyways this next go around. Basically at a loss and looking for recommendations.

 

Damn man, this is crazy. Wish I had some recommendations but if it were me I’d be asking you for some.

 

You mentioned checking the bottom end. Bearings? Not likely but, possibility of spinning one?

 

Oil is crystal clear and the filters have no metal in them. No abnormal noises either. Very doubtful on a spun bearing at this point.

 

Engine is going to be completely torn down either way at this point.

 

Only one way to find out what it is. Let’s hope it’s the last time! I know this must be beyond frustrating! At this point I hope it’s something clearly out of place....bc everything looking good but somehow there’s an issue is the absolute hardest scenario to troubleshoot. Sounds weird to hope there’s something.....but in this case I’d say they’re better be...so you can move on and get it running

 

I mean gives me time to do some more upgrades that I DO want to do either way, just kind of bending my arm to get it done.

 

Any chance one of the replaced items is bad out of the box? Too bad you can't run it out of the car and look at readings on a bench. It would be easier than pulling it out the vehicle every time.

 

The only one that technically would matter would be the oil pump and it seemed to be pushing pretty good when using the mechanical gauge. We also checked my original block for any extra unplugged holes and can't find anything. We tracked the entire oiling system through the block. How it runs to the heads and mains etc and everything is in order. Just something's off. It idled for more than long enough to cycle oil everywhere. I'm just at a loss lol

 

What kind of time-frame is this? 10 seconds? 10 minutes? Is it linear over time or a sudden drop? Seems like a bearing tolerance issue. Did you get a build sheet? The solution might be as simple as running heavier oil.

 

Hi Jordan.

I would say that you have a leak somewhere. I keep oil pressure stuff simple. Pumps creat flow. Restriction to flow creats pressure. Knowing you have no metal debris and low pressure I would have also gone after the pump thinking the oil pressure relief valve is sticking open or faulted.

So running that out, if there isn't excessive clearances in your rotating assembly I would say your leak is in your heads.

I havent been following your build. Whats been done to the heads?

I can't find an oil flow chart for the 3.5gtdi Taurus, but found it for the exploder.

I dont remember how the vct system works for oil flow.

 

Is the oil capacity of this motor the same as stock? Just wondering if oil cavitation could be causing the pressure drop. If it is over filled that is. Just a thought. I am sure this is not it but have not seen it mentioned in the discussion.