akw408

Okay, this is going to be long, but just want to make sure people know the full story, so...

I recently put in a new oil pump because the previous one had a stuck relief valve. It was a ported oil pump. I had noticed that the oil pressure had started to read lower at idle than when I first got the motor (which was only about 3500 miles ago).

Anyway, I put a stock oil pump in and now the oil pressure is reading even lower, probably because the ported oil pump had some shims with the spring. But now, the oil pressure is like 28psi cold at idle and 16psi hot at idle, 10W30 Mobil 1. This is about 10-15psi lower than what I had with the ported oil pump. It's not the o-ring gasket on the oil pump pickup tube because I saw the mechanic put the gasket on the tube before he put the pump on. As far as I know, that's all you need to do right? It'd be great if it was a bad gasket, but right now I don't think that's it since I saw him put it on with my own eyes.

And what's really puzzling is when I start driving, no matter what temp the oil is and what rpms I'm at (up to around 3500rpms), the oil pressure always stays around 32-36psi. I would figure the oil pressure would drop when the oil gets hot, like it does at idle. But it's not like that, at any temp and rpm, the oil pressure is always 32-36psi. I haven't reved past 3500rpms yet, but I have driven it pretty hard up to 3500rpms and the car runs great. No knocking, nothing. I would have no idea anything was wrong if I didn't have an oil pressure gauge staring me in the face. It's as smooth and quiet as any car with my cam and Comp R lifters could be, I think.

So I figured it might be the oil pressure sender, replaced that. Same reading basically. The last things I can think of are bad oil pump (don't know what the odds of that are) or worn bearings. But the bearings are only 3500 miles old, but maybe when I started my car with the relief valve stuck, it caused some damage. But I only had the car started for maybe 20 seconds max. But I guess it could happen. For those that have had bad rod bearings before, what was your oil pressure at? And what kind of behavior did your oil pressure have, like did it build up quickly and then go down slow? Is there anything else it could possibly be besides the oil pump and bearings? Those are the two obvious things, but are there other things that could cause low oil pressure? Is there any screen for the oil pump pickup that could be clogged?

I am pretty puzzled. The oil that was drained out of the car when doing the oil pump swap was pretty clean and did not show any bearing material (to the naked eye). I plan to drive the car for maybe 300 miles or so and then drain the oil and get the oil sent to some oil test lab. But right now, honestly, bad bearings doesn't seem like a high likelihood because the car just runs so smooth. Or am I fooling myself? Anyway, any suggestions would be great. Anything I haven't checked yet or thought of?

<small>[ November 17, 2002, 08:03 AM: Message edited by: akw408 ]</small>

StevieZ

iTrader: (3)

Maybe the O-ring is there but improperly seated and letting air in??

bae_98Z

The o-ring may have ripped when installing... Happened to me.

Kyung

akw408

</font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by bae_98Z:
<strong>The o-ring may have ripped when installing... Happened to me.

Kyung</strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">When it happened to you, what did your oil pressure look like? Does it sound similar to what I see? And was it a stock or ported pump?

If you put the o-ring on the pick up tube and slide the pump onto the pick up tube, are there really parts of the pump that can pinch or rip the o-ring?

DrkPhx

iTrader: (15)

There is nothing there to pinch the o-ring. When the tube is seated properly the rim of the tube sits directly on the oil pump. Whose ported oil pump is it?

Also make sure you have enough oil, I run 6 quarts.

<small>[ November 17, 2002, 07:07 PM: Message edited by: BLKTA ]</small>

akw408

</font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by BLKTA:
<strong>There is nothing there to pinch the o-ring. When the tube is seated properly the rim of the tube sits directly on the oil pump. Whose ported oil pump is it?

Also make sure you have enough oil, I run 6 quarts.</strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">I put in a stock oil pump. And the oil level is full. I was pretty sure it wasn't the o-ring, because I saw it installed, but I guess it's one more thing to check.

Is there any kind of screen before the oil pump where anything could get stuck?