HELP, no oil pressure...!

[fred cook]

After looking at the oil flow diagram, I believe that my next step will be to drop the driver side SSI heat exchanger (ugh!) and check the safety valve on the bottom side of the sump. Since that is the first thing "down the line" from the pressure side of the pump, any debris such as a piece of the oil seal might show up there. And, if the safety valve is being help partially open, that would explain the oil pressure drop. As I said earlier, the scavenge side of the pump seems to be working well, maybe even better than before the rebuild. Since my engine and Jesper's engine are experiencing the same symptoms, maybe I'll find an answer for both of us! Wish me luck, I'm Goin' In!

[Walt Fricke]

Jesper

The engine oil thermostat, which prevents oil from going through the engine mounted oil cooler when the engine is cold, and directs it there when the engine is hot, has a failure mode. When it fails, oil doesn't flow through the cooler no matter how hot the oil gets.

If there were a correlation between oil pressure drop and oil temperature in daily or track driving - if the oil got "too damn hot" as Bruce Anderson used to put it - a bad thermostat could be at the root of things - engine gets too hot for oil's viscosity. But that is a much longer term effect than you are describing with your motor. An engine idling or being driven for a few minutes without pushing it isn't going to build up that kind of heat.

[jsveb]

Walt, thanks

The oil temp of my engine never got above Approx. 80C

-Where does this leave me?

-What do you suggest I check?

[Flat6pac]

Jesper, i still think you need to look in the pressure reliefs, both in your hand and make sure there isnt any thing snagging them and keeping them seated. If you ruin the cap, I m sure I have extra in the parts drawer.
Bruce

[Walt Fricke]

I don't have any suggestions beyond what Bruce says and you have been trying to do.

Rereading this discussion, I don't see where you say that after the initial higher reading, and the quick drop to 1 bar or so, you then recorded oil pressure at 1,500 rpm, and 2,000 rpm, and 2,500 rpm, and 3,000 rpm, and maybe higher. So you can see if it hits a rather low plateau at very low RPMs and never rises, or whether oil pressure actually does rise some with RPM, just not at the rate of climb you want.

Fred's seems to be the later.

[jsveb]

Thanks Bruce. I will try and do that.

Regarding oil pressure. When I rev the engine, the oil press doesn't climb proportionally. It just stays down.

[fred cook]

Had a note from another PP member, he suggested this:

Hey.
I have a thought about your oil pressure problem.
Are you running oil fed tensioners? If the valve on a tensioner had come apart or fell out on the right side of the engine where the oil pressure sender is located, it would definitely give you lower readings as there would be a unrestricted flow of oil leaking out of the tensioner. just a thought for something to check into.
take care and good luck

[fred cook]

Originally Posted by jsveb

Thanks Bruce. I will try and do that.

Regarding oil pressure. When I rev the engine, the oil press doesn't climb proportionally. It just stays down.

My engine was doing this and I replaced the oil sender at the rear (pulley end) of the engine. Turns out that the old sender had decided to go bad while off the engine. I replaced it and now the gauge will respond at least some. With the engine warm, the gauge is showing 2 bars of pressure at about 4K rpms. At idle it drops to about 1/2 bar.

On another topic, does your engine have the Carrera pressure fed tensioners? If so, when you had the top end work done, were they changed for new ones or did you reuse the old ones?

[jsveb]

I have changed the sender once to check that part, wasn't it.
I then mounted a wet gauge at the same location as the oem sensor to check the dash gauge.

The wet gauge pretty much agreed with the factory stuff.

It does have hydraulic tensioners, I don't think they were replaced, but it am not certain.

The car is just sitting, I have zero time to work on it - aaaargh

[jsveb]

I had an hour in the garage this afternoon. I managed to pull the right side headers off and the cross-over tube.

The pressure release plug was on really tight. But eventually it gave in and I hit my elbow hard on the engine, oil pipe and muffler clamps, but it was worth it...progress

I peaked in there after pulling out the plug and the spring. I used my Bluepoint pencil magnet,cand was able to pull out the piston.

except for the last part it was nice and smooth in the bore. by the last part, i mean jusrt before it exits out past the threads. i dont think this has anything to do with this problem.

If family allows... I will go out there again and pull the safety valve as well. just need to remove the LH side headers as well.

[jsveb]

Just back in from the garage.

I have removed the safety valve as well. I don't think that's it either. There was no debris in there. The piston was moving ok, with only slight binding which may be caused by an off center pull or moving it beyond the intended travel.
Pictures, let me know what you think:


You can see some wear on the piston, is this OK?



I decided to remove the valve covers to see if there was any obvious damage:




Based on this, I got two questions. I could find nothing apparently wrong. Do you see anything?

Where do I go from here, what's next?

[fred cook]

Originally Posted by jsveb

Just back in from the garage.

Based on this, I got two questions. I could find nothing apparently wrong. Do you see anything?

Where do I go from here, what's next?

It appears that the rockers are oily, indicating that at least some oil is being fed to them. That's good! I agree, based on what I could see in the pictures, everything appeared to be where it is supposed to be! So, where to go next? At this point, I am pretty convinced that your engine and my engine are experiencing the same problem. So, if we can solve the puzzle for one, we will solve for both. The only real difference between the two is that I split the case and you did not. That tells me that the issue is somewhere outside the block. Keep the faith, eventually we will solve the question!

[JJ 911SC]

Fred/Jesper

I feel for both you guys.

Right now I'm having problem with basic EFI tuning and its driving me banana (just like Walt with his #5 not firing right problem).

Hang in there, eventually we'll get there

[jsveb]

Well, I have it back together except for the exhaust, which will need some gasket sealer due to some of the exhaust studs not having very good threads, and this I can't do until I get some oil since the gasket speaker will need heat to cure.
I will get some rotella T this time since it is cheaper than the VR-1, and frankly I suspect I'll have to drain it after testing.

I ordered a new plug and some washers from pelican to make sure it wouldn't leak etc.

When I wanted to install the safety valve piston, I actually noticed some small black flakes of some sort. I don't know what is was or where it came from. I was wearing brand new vinyl gloves, so I don't think I introduced it.
Anyways, I cleaned out the bore real good, and installed piston and spring.

As mentioned, next will be oil and exhaust and then fire it up, hoping for the best.

[jsveb]

After I cranked up the car, I had two immediate thoughts.

2. I wish you, Fred, get your car sorted ASAP.

1. Yes!!!

When I fired it up. The oil pressure went up to about 6 bar, and stayed high.

After checking for leaks and such, I took it for a spin. What a thrill!

The oil pressure stayed good, between 3-4 doing second and third gear on back roads.

I don't know what it was, the only thing I have messed with, was removing inspection and cleaning the two pistons.

All I can say is, if I do a rebuild in the future, these two items will be included in my to-do list. Way to much grief.

Thanks for the feedback guys. I'll report back if the situation changes, hope not.

[fred cook]

Originally Posted by jsveb

After I cranked up the car, I had two immediate thoughts.

2. I wish you, Fred, get your car sorted ASAP.

1. Yes!!!

When I fired it up. The oil pressure went up to about 6 bar, and stayed high.

After checking for leaks and such, I took it for a spin. What a thrill!

The oil pressure stayed good, between 3-4 doing second and third gear on back roads.

I don't know what it was, the only thing I have messed with, was removing inspection and cleaning the two pistons.

All I can say is, if I do a rebuild in the future, these two items will be included in my to-do list. Way to much grief.

Thanks for the feedback guys. I'll report back if the situation changes, hope not.

On finding/solving your oil pressure problem! It appears that one of your oil pressure relief valves was not seating completely. I checked both of the valves on my engine but with no success. Looks like I will be splitting the block again to change out the oil pump and block seals with a different brand of seals. At least everything is new and clean this time!

[mreid]

Having followed both this thread and Fred's thread since the beginning, I feel for you both. First, congratulations, Jesper, that is a wonderful feeling!

I've had a similar problem in that my 75 2.7 CIS engine starts with 50 psi, but within 2 minutes it drops to zero. When I rev it, the pressure comes up to around 25 psi, but drops back to zero at idle.

Yesterday, I replaced the old spring loaded tensioners and sump plate. The plate was installed with the drain plug towards the rear of the car and some po had jacked up the rear of the car, denting the plate. When I removed the plate, the dent was right under the pickup. I also noticed that in all the pictures in Wayne's book (at least the ones I was looking at), the plug is oriented to the side. Long story short, I started the car and the oil pressure went up to 50 and then only when warm dropped to about 20 psi, increasing with rpm. My problem seemed to be a restriction at the pickup.

Probably doesn't help you, Fred, but at this point any tidbit of data has to be helpful. Good luck!

[fred cook]

Originally Posted by mreid

Having followed both this thread and Fred's thread since the beginning, I feel for you both. First, congratulations, Jesper, that is a wonderful feeling!

I've had a similar problem in that my 75 2.7 CIS engine starts with 50 psi, but within 2 minutes it drops to zero. When I rev it, the pressure comes up to around 25 psi, but drops back to zero at idle.

Yesterday, I replaced the old spring loaded tensioners and sump plate. The plate was installed with the drain plug towards the rear of the car and some po had jacked up the rear of the car, denting the plate. When I removed the plate, the dent was right under the pickup. I also noticed that in all the pictures in Wayne's book (at least the ones I was looking at), the plug is oriented to the side. Long story short, I started the car and the oil pressure went up to 50 and then only when warm dropped to about 20 psi, increasing with rpm. My problem seemed to be a restriction at the pickup.

Probably doesn't help you, Fred, but at this point any tidbit of data has to be helpful. Good luck!

might be the problem on my engine. However, I pulled the sump plate off to make certain that it was oriented correctly and found that it was. The sump plate on my engine does not appear to have been damaged or dented so I tend to think that is not the problem. I have considered putting an extra gasket under the plate just to see if the extra spacing makes any difference.

[HawgRyder]

Fred...remember...it only takes a microscopic piece of dirt to inhibit the pressure relief valves!
If the crud gets stuck in the wrong place it can run you around the bush many times trying to find it.
Bob

[jsveb]

Originally Posted by Flat6pac

Jesper, i still think you need to look in the pressure reliefs, both in your hand and make sure there isnt any thing snagging them and keeping them seated. If you ruin the cap, I m sure I have extra in the parts drawer.
Bruce

I just want to awknowledge Bruce advice above - thanks!

I am really looking forward to take it for a spin again soon. Just to confirm all is good.