low oil pressure

[Racer X]

1 hour ago, Wally said:

Not what i did. Here is what i did. I put my torque on something low like 20. i tried to tighten the bolt. It clicks. so i move it to 21, click and so on until it doesnt click anymore but begins to tighten a little. I know that is odd way to do it but that is what i did

Still not an accurate method of checking the actual applied torque.

As I mentioned previously, a bar or dial type torque wrench will show a better, more accurate indicator of where the fasteners were, but as The Captain pointed out, there is the static friction which must be overcome, and the true torque applied can not be accurately checked.

All you are doing is determining the torque required to overcome the static friction of the fasteners.

 

 

[Captain Obvious]

1 hour ago, Racer X said:

Still not an accurate method of checking the actual applied torque.

All you are doing is determining the torque required to overcome the static friction of the fasteners.

What he said. And it doesn't matter whether you are tightening or loosening. The mechanics of the static friction are the same.

I'm not trying to cast dispersions on your work, but what I'm saying is don't get all caught up in the absolute numbers you think you are seeing. I'm saying that just because YOUR wrench doesn't click until 50 ftlb on a fastener that was supposed to be torqued to an upper limit of 40 does not convince me that bolt was originally torqued higher than the spec.

So you've got an engine with a bunch of time and heat cycles on it. And when you used your torque wrench (with some unknown accuracy), it took more torque than spec to move the bolts that have been in there for some time. No surprise there.

[Wally]

I understand thanks. At this point nothing more i can do about that. I have another torque wrench coming in today to verify all the current torque settings to degree possible. I think having them bolts set at proper torque specs is best thing i can do at this point going forward.

[Zed Head]

Even if they were over-torqued that's not going to be the cause of your problem.

You've spent a lot of words on torque settings.  How did the parts look?  The pickup tube and the bearing clearances?  Not seeing any signs that you found the source of low pressure.

[siteunseen]

Apparently I've bumped my head and missed a few days.

You were driving it a few days ago and had a gauge on there showing it was dropping psi with higher engine speed. Now you're able to remove the main bearings.

Since it is apart take the oil filter off and push on that shiny metal ball and check how stiff or soft it is to push in. Just for poops and giggles I'd like to know. It should be about as hard to push down as poking in the sidewall of the tires a little bit. Pretty hard I'd say. Thanks

[Zed Head]

He said he checked it in post #55.  But that would not cause his system pressure problem.  It just bypasses the oil filter.

Won't be a surprise if the problem remains when it's all back together.  

Here's a question for the engine builders.  Maybe it's in Monroe's book.  Are there oil galley plugs that could be loose or missing?  Of course, they would have to be internal since there are no huge oil leaks.

I just did a quick Google and found a reference.  Different engine, still Nissan.

https://www.311s.org/phpBB3/viewtopic.php?t=10024

[Zed Head]

Here's another interesting thread from before my time on the forum.  Says that there are also crankshaft plugs.  Makes sense, anywhere a passage is created there will be an end that needs plugging.

 

[Wally]

2 hours ago, Zed Head said:

Even if they were over-torqued that's not going to be the cause of your problem.

You've spent a lot of words on torque settings.  How did the parts look?  The pickup tube and the bearing clearances?  Not seeing any signs that you found the source of low pressure.

everything looked super clean, brand new. no scuffs, nicks... nothing.

[Patcon]

I agree with Zed's thought process. To have lower pressure than idle when revving would be an exceptional loss of pressure. So open oil galley. Bad oil pump. Missing or broken spring in the oil pump(an easy check). Something really strange...

[Wally]

I havent read all recent posts yet....but i may have made things worse.

I put everything back together per service manual specs. New oil pump, new Filter etc..

I turned car on and car dash gauge registered absolutely nothing. I put in the mechanical oil gauge. At idle it showed 38 and when i revved engine up it hit 55.

Not sure if this is good or bad.... i will get a helper and take some #s at certain RPMs and post.

 

Edited February 4, 2023 by Wally

[Patcon]

I would much prefer my dash gauge being wrong and having 38 psi at idle and more revving than what you had before. Now you have a gauge issue but not a mechanical engine issue! I would consider that progress!

[Zed Head]

Did you turn the Nissan gauge by the body and not by the nut at the base?  You can twist the wires off inside.  Sounds like an electrical problem.

At least you have good numbers.  Mystery unsolved.  Cause not found.