I'm sorry, but that just isn't correct. The reason you have a loss of oil pressure due to bearing failure is the increased clearance. You have that no matter where the crank is. You either have it at one end or the other...depending on whether or not the thrust side is "loaded". The oil will leak from one side or the other.

I'm not saying he doesn't have a thrust issue...I'm saying the reasoning isn't correct. Now, if the thrust was so bad that it allowed the crank to move far enough that it uncovered an oil hole in the block, that's different. But man...that thing would have to be moving a LOT to do that.

 

What do mean moving a lot? I had .040 of movement and all the crank counterweights were rubbing ridges in the main caps and supports from forward push. The crank walked UNDER LOAD only, and that's where you saw an oil pressure dip. At idle it was fine. So what I said is still right

 

Thanks for all the help. I will be pulling my motor and bringing it to the machine shop, most likely will get some new heads to go with the cam, depending on how much they tell me it is to refresh them. I got a quote from a sponsor to do the motor, $4000 to refresh the motor while keeping the stock heads and the cam in it. Im pretty sure I can do it cheaper than that.

 

Have you measured endplay yet?

 

No, can you do this with the motor in the car?

 

Yep, remove the two belts on the front and get a prybar and a dial indicator with a metal base. Set the indicator to measure the crank pulley's forward movement, and pry it forward while watching the dial. Pretty simple. Working from under the car of course.

 

Good conversation here...

My question to you is...

If you have .040 clearance, it does not change whether you are at idle, WOT or anything in between, right? So why does where the crank is located make any difference in oil pressure? Whether the crank moves forward, backwards or in the middle, it always has .040 clearance regardless. Unless it moves far enough to uncover an oil feed hole, (doubtful at .040) it should make no difference.

 

Ill have to get a dial indicator, probably go to harbor freight

 

If you pull the car up on ramps, you could have the belts off and have your measurement in 10 minutes or less. I pry softly against the front cover with a HF prybar. You stick the prybar between the front cover and the pulley and when you push towards the rear, it pushes the pulley forward. Don't go crazy, go easy. If your endplay is within spec .004-.008 then the pulley isnt gonna move much and you are going to have to pay attention to clearly see it. It will make a light tap and then when you release tension it will settle rearward and tap again. On an engine with .004-.008 endplay, you can force the crank to go further by prying. So be gentle and feel for the free movement. If you get a huge clunk forward, that would be a trashed thrust bearing.

 

I just measured it, took the belts off also. It came out to .003 to .005". Seems ok to me. Im going to get a mechanical oil pressure gauge and hook it up and see what it does.

 

On stock motors in good condition I usually measure about .004.

 

So it sounds like Im good on that end. I was going to put a mechanical gauge on but its a pain with the BBK intake, I ended up taking the intake off and putting a new sending unit on, oil pressure still drops.

Its odd how it doesnt do it everytime though. Why would this be?

 

Well no replies and I was bored.

I pulled the motor apart, going to check that O ring to see if its pinched.

 

I pulled the oil pump out, o ring was not pinched. Took the pump apart, didnt see anything odd. I put it all together and took it for a drive.

So 18 miles to work today, must have floor it in 2nd gear alll the way up to 6800 rpms, oil pressure stayed at 45 to 50 psi. It did this all the way to work when i floored it. Of course it was raining on the way home, so I couldnt get on it, but when revving it in neutral to 6000, oil pressure is about 55 to 60 psi.

So, thats about where I am at.

 

Things that make you go h-mmm. Good luck with it.

 

6800 rpm on stock 99' rod bolts

as you said, you have metal in the oil, why bother with anything else, whats the purpose of the mechanical gauge at this point? accept the fact that there is a bad bearing in your motor and the more you drive it the more its getting fucked up. you should have installed the oil pump pickup tube girdle.

 

So i have a lift now, pulled the motor out the bottom. I just took the heads off, lifters out and cam.

So the culprit is a couple flat lifters and a couple flattened lobes. Looks like i am going to have to rebuilt her.

 

Mystery unraveled.

 

So I assume this was caused by lack of oil pressure?

 

Wow, don't hear many people wiping cams out. How are the bearings?