Oil pressure woes
#31
Rennlist Member
You're not quite understanding how the parts interact.
Here's a picture I found on a google images search. Those two gears are the actual oil pump part - that gear set is upside down in the pic so you can see them... the side you see goes against the inside of the aluminum pump housing. The oil only goes between the sets of teeth, no where else. There is no oil interaction between the oil pump drive sleeve (which has the spline on it) and the inner gear.
As you say, "if air was getting in there" it couldn't get inside the gear set... The oil you see coming out and making a mess is residual oil that's supposed to drain back into the oil pan. Because your front seal is old and brittle, and because the oil pump drive sleeve has a groove, a small percent of the oil draining back into the pan is working its way past the seal and making a mess.
What you need to do is take out the OPRV and crank the engine over. If not much oil is coming out of the hole, then there is a problem on the suction-side of the oil pump system - which is the oil pickup tube and the passage way between the girdle and the block. If the pump is really "pumping air", then dollars to donuts it's a crack oil pickup tube. Of course out-of-time balance shafts or bad engine mounts can contribute to the pickup tube cracking, but I see no reason why the tube *can't* crack even if those are good.
Here's a picture I found on a google images search. Those two gears are the actual oil pump part - that gear set is upside down in the pic so you can see them... the side you see goes against the inside of the aluminum pump housing. The oil only goes between the sets of teeth, no where else. There is no oil interaction between the oil pump drive sleeve (which has the spline on it) and the inner gear.
As you say, "if air was getting in there" it couldn't get inside the gear set... The oil you see coming out and making a mess is residual oil that's supposed to drain back into the oil pan. Because your front seal is old and brittle, and because the oil pump drive sleeve has a groove, a small percent of the oil draining back into the pan is working its way past the seal and making a mess.
What you need to do is take out the OPRV and crank the engine over. If not much oil is coming out of the hole, then there is a problem on the suction-side of the oil pump system - which is the oil pickup tube and the passage way between the girdle and the block. If the pump is really "pumping air", then dollars to donuts it's a crack oil pickup tube. Of course out-of-time balance shafts or bad engine mounts can contribute to the pickup tube cracking, but I see no reason why the tube *can't* crack even if those are good.
#33
Rennlist Member
If you're going to remove the pan, check that oil pickup tube first...
Support the engine from the top, remove the cross member, and then you can remove the oil pan.
Support the engine from the top, remove the cross member, and then you can remove the oil pan.
#35
Burning Brakes
Join Date: Dec 2009
Location: Montreal, Quebec, Canada
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Before you pull the oil pump I would check the pickup and the pickup seal. My experience is that its not that likely that the problem is the oil pump.
#36
Drifting
Thread Starter
To get at the tube I have to pull the pan. At that point there is no point to not pulling the pump. It's gonna be such a pita it's not even funny. I'm fighting the idea of dropping the pan. I think if I can loosen the pan enough to get the pump off I can at least check visually to see the tube is cracked. My bet is that there is a bad seal against the block on the back side of the pump.
#37
Drifting
Thread Starter
Ok! Got an oil pump from a buddy. When we were pulling the pulleys from the front of the motor, I noticed that there was another washer on that oil pump that was not previously noticed on mine. I don't specifically remember if that concave washer was inside the drive sleeve or not. As it is I am beginning to remember hearing that the incorrect installation or lack thereof can cause oil pressure issues. I did not think this to be a problem on mine, as I don't recall it being there when I took it apart last year and it has run without oil pressure issues to this point.
Which brings me to this question. Could this be the issue?
Also since last night I have seems to misplaced same. Major face palm!!! I hope it's still in his driveway or somewhere in the bowls of my trunk. Otherwise I'm going to be pulling the pan and pump for absolutely no reason.
If it doesn't turn does anyone happen to have one??
Which brings me to this question. Could this be the issue?
Also since last night I have seems to misplaced same. Major face palm!!! I hope it's still in his driveway or somewhere in the bowls of my trunk. Otherwise I'm going to be pulling the pan and pump for absolutely no reason.
If it doesn't turn does anyone happen to have one??
#38
Burning Brakes
Join Date: Dec 2009
Location: Montreal, Quebec, Canada
Posts: 1,045
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Ok! Got an oil pump from a buddy. When we were pulling the pulleys from the front of the motor, I noticed that there was another washer on that oil pump that was not previously noticed on mine. I don't specifically remember if that concave washer was inside the drive sleeve or not. As it is I am beginning to remember hearing that the incorrect installation or lack thereof can cause oil pressure issues. I did not think this to be a problem on mine, as I don't recall it being there when I took it apart last year and it has run without oil pressure issues to this point.
Which brings me to this question. Could this be the issue?
Also since last night I have seems to misplaced same. Major face palm!!! I hope it's still in his driveway or somewhere in the bowls of my trunk. Otherwise I'm going to be pulling the pan and pump for absolutely no reason.
If it doesn't turn does anyone happen to have one??
Which brings me to this question. Could this be the issue?
Also since last night I have seems to misplaced same. Major face palm!!! I hope it's still in his driveway or somewhere in the bowls of my trunk. Otherwise I'm going to be pulling the pan and pump for absolutely no reason.
If it doesn't turn does anyone happen to have one??
#39
Drifting
Thread Starter
So it seems the "missing link" is actually a green o-ring. I'd bet dollars to donuts I have one in the tool box. According to the Porsche dealer I talked to it's a 28x2.58 mm I ring.
#41
Drifting
Thread Starter
Yup! I'm going to go back together with it. I know for a fact that I ring was not there when I took it apart Saturday. Worst case if I still have priming pressure issues I'll drop the pan. May not get home in time today to work on it but tommorow
#42
Drifting
Thread Starter
Well this sucks!
I was hoping against hope that my problem was as simple as a lack or torque or missing o ring. Nope!
Next step is to lower the pan enough to remove the pump, maybe visually inspect the pick up tube.
If I don't see any visual confirmation of lack of seal between the pump and block, it's going to be a big disappointment. Will also mean completely removing the pan, and re sealing the girdle unless there is obvious cracking on the pick ip tube.
So! Wish me luck!
I was hoping against hope that my problem was as simple as a lack or torque or missing o ring. Nope!
Next step is to lower the pan enough to remove the pump, maybe visually inspect the pick up tube.
If I don't see any visual confirmation of lack of seal between the pump and block, it's going to be a big disappointment. Will also mean completely removing the pan, and re sealing the girdle unless there is obvious cracking on the pick ip tube.
So! Wish me luck!
#45
Rennlist Member
If oil is copiously squirting out, then you have a problem after the oil pump. If nothing comes out, or if its just a dribble, then its the pump or something earlier.