Update: changed the oil to 20w50, but the pressure is still 0 psi at idle when warm.
Could this mean that the bearings are fine, and the oil pump is causing this?

Also, the mechanical pressure gauge was installed at the bottom of the block above the oil filter and I got the same readings as as the gauge in the dash whish reads from the top of the block.

 

Ok, I'm a bit confused then. I ran my car with no oil pressure for 30 seconds and it seized up quick. It dragged the tires down the road when it happened, till I pushed in the clutch. So, if his car is idling fine, it MUST have SOME oil pressure, correct? Could it not be just enough for the bearings, and when above idle, all is good? I just don't see how a car can realistically run for 4 months with no oil pressure. Maybe he used ZMAX in it??

 

Couldn't say!!!!!!!!!

 

So, it it fair to say that since pressure didn't increase after putting 20w50 in -- that oil pump is probably causing this?

 

Got a 50/50 chance.It's either brgs or pump IF the manual guage is working correctly that ya checked it with.
In any event the engine should be torn down for inspection and replacement of any worn parts and an oil pump is automatic.
It could be a welch plug in the lifter galley's came out,who knows,it just needs to be torn down and checked before it get's REAL expensive.

 

Is this on a stock motor or rebuild?

 

BTW... (and im surprized i'm the first to say this) Oil pressure doesn't mean crap. Well, it does, but let me explain... If you have bad oil pressure, there is a reason. Just fixing increasing oil pressure will not solve anything... If the problem is bearings, which it probably is, then puting a high volume pump in, or changing the pressure relieve spring, or putting thicker oil in, isn't going to fix your problem. Yeah, it will give you higher pressure, but it won't fix what's wrong with the engine. My advise... tear it down and take some measurments... And it's not always just a spun bearing... they could just be worn.


EDIT: I forgot something... it could just be a bad pump too... start off by replacing the oil pump with a stocker... not a high volume. High volumes arn't always bad, but your tryin to find your problem. A high volume in your situation, right now anyway, might give you a false sence of "fixing the problem."

 

This is a completely stock motor, only 80k on it. For what it is worth, I took the valve covers off, started it up and oil is definately getting to the top of the block.

I'm replacing the pump next week and will take a look at the bearings while I am at it. How hard is it to drop the oil pan for somebody who has never done it before?

 

Put the pump in and run it. If a bearing was bad, you'd have heard something abnormal. I've run zero oil pressure for 20-25 miles at freeway speeds. I don't know, maybe 3000 RPM. Thot the gauge was wrong. Didn't touch a bearing. The one ******d sign was a dull main bearing thump at idle. The SBC is about as easy as it gets to oil. An engine builder once remarked you could oil a SBC with an oil can. Joking of course, but it don't take much. Don't make a mountain out of a mole hill.

What the hell. What is wrong with the word ******d? ******d... ******d.. Software getting paranoid. ******d OK. Here we go. OUT...WARD... O.U.T.W.A.R.D!!! Looks like I invented a NEW dirty word. Now that I've circumvented the language software, what's next? If the moderator makes house calls, I'll run out and get some beer to put in the frig.

 

I have had trouble with that word, too.

 

******d

Well, I dont think its going to sieze if it hasnt yet, my car started knocking and acting up..(power loss) immediately following low pressure. Goodluck! You must feel like youre on thin ice!