Yeh it drove me crazy for a while, The engine was new(1000 miles) I was running it one day and looked down at the oil pressure right before I was going to shift and it was dropping. Only did it in the upper rpm ranges under heavy load. Kept seeing the silvery metal stuff in the oil after repeated oil changes so I pulled it out disassembled it upside down on the stand and found nothing...two days later I flipped the engine block back upright on the stand and found the cam bearings eaten up on the bottoms.


David

 

I will try new oil tomorrow. I will put 4 quarts in and see what happens. I believe the pump is an M55s. I measured the distance from the tube to the bottom of the pan with info from this site. I assembled it and marked the position. I took it and had it tacked. If it is a bearing problem I will have to park my car. I simply can not afford to fix it right now.

 

The engine I lost last summer to a spun main had similar dropping oil pressure symptoms. Then the vibration started. It all happened in less than a hundred miles.

 

I am going to pick up some oil tomorrow. I have a new AC filter I am going to put on. Does anyone have a suggestion on brand and weight of oil I should try?

 

What does your machine shop recommend?

 

He didn't have any recommendations as far as oil goes. I usually put 5-30 Penzoil in it. I was just wondering if one brand is better than another. I am not going to try synthetic this time because there may be other problems.

By the way, the pump is a M155

 

i just had this exact same problem. finally figured it out today. last night I started up the car at work and BAM no oil pressure. I was freaking at this point. so I had it towed home. First I dumped out the oil. No glitter so that is a relief. I'm sure it doesn't mean no damage but...

I stuck a screw driver in the low oil sensor hole and I could feel the p/u was in place.

So I pulled the intake and yanked out the drive gear in desperation of not having to pull the engine.

it was the drive gear. half the teeth are missing. not sure what happened there... now I wonder where those missing teeth are???

 

I had that happen on my old engine. I found the teeth in my pump and filter. This is completely different. It has oil pressure until I am under a load. I found several posts that are similar to mine. Most of them were also missing the windage tray. I am going to change my oil and see what that does. I am currently trying to find an oil pan with a built in tray or a tray that works with factory main bolts with the studs.

 

yea mine was under load only as well. usually only 1st and 2nd when I would really get on it. I would have 55-70psi cold 40-50 warm then 20-30 if I stepped on it

 

I will check this also. I just hope I don't have to pull the engine.

 

Update: I changed my oil and put 4 quarts of 10-30 in it. It is keeping good pressure now. It is not losing it under a load and it is behaving like it did before. I have some questions. What would have caused this? Will it hurt anything to run it a quart low? I plan on putting a windage tray in it this Summer. What is the part number for the factory piece? Is there a better one that will work with the factory bolts?

 

I would think it is a windage issue which means the next step would be to take the pan off and see what is happening. Was the stock baffle modified in any way for the new engine?

 

The pan is stock and I left the factory tray out simply because I didn't have one. I have the bolts that hold it and I will probably go back with a stock one. I am not looking forward to dropping the pan. Now I need to find a part number for the factory tray.

 

the part number for the oil deflector tray that I have is 12554816

 

Wow... I was confused. I thought when you said the baffle was in there you meant the tray.