Oil Pump Spring?

[Giamanut]

First, I'm not trying to step on your toes but simply clarify/correct the stated operation for the benefit of others...

Weather the excess goes back to the crankcase or pump matters when explaining/understanding the system.

There is more to it than semantics-
"Maintaining a given PSI" is not the same thing as "regulating/limiting/bleeding off it to a spec max oil pressure." The former yields a constant pressure. (The pressure regulator in the FD (PPR) is a good example.) The latter yields varying pressure, up to the spec. (Which is how the oil pumps actually work.) The PPR maintains -- The OP relief valve limits.

I get that totally agree but the way the PPR is Constant Is because the Pump Is Constantly above Valve working Pressure! Electric pump vs mechanical but when either is at Valve working pressure they work Identical. Poppet and spring.
Think about this for a second say your an engineer and you have to lubricate any mechanical system you know there is an ideal pressure but you can not get that ideal pressure 100% of the time because at 0 rpm you have zero pump pressure from a mechanical pump. Plus cold vs warm oil, etc etc all you can do is relive pressure at the Ideal psi on a warm engine at the most used rpm I am not saying you are going to maintain a given oil pressure at all rpm at all under the valve working pressure it is going to go with rpm. What I am saying is that Max oil pressure is By Design and most oil pumps will have an inherent Max PSI at any RPM 75 maybe 85 psi maybe even 100 psi.
The biggest difference in or train of thought here ( which is good by the way) is this you say the oil pump valve is designed to protect the oil seals / filter etc from over pressure, and it does do that however I say it is designed to provide the best possible lubrication. In short the Oil Pump is not designed around the seals rather the seals are designed around the Best Possible Lube. The valve in the FD and the Oil pump function on the same principal, but the PPR has a constant 100 or more psi behind it from a constant speed pump. The difference is in the pump not the function of the valves.

[Ron]

I get that totally agree but the way the PPR is Constant Is because the Pump Is Constantly above Valve working Pressure! Electric pump vs mechanical but when either is at Valve working pressure they work Identical. Poppet and spring.
Think about this for a second say your an engineer and you have to lubricate any mechanical system you know there is an ideal pressure but you can not get that ideal pressure 100% of the time because at 0 rpm you have zero pump pressure from a mechanical pump. Plus cold vs warm oil, etc etc all you can do is relive pressure at the Ideal psi on a warm engine at the most used rpm I am not saying you are going to maintain a given oil pressure at all rpm at all under the valve working pressure it is going to go with rpm. What I am saying is that Max oil pressure is By Design and most oil pumps will have an inherent Max PSI at any RPM 75 maybe 85 psi maybe even 100 psi.

When the PPR valve is at its working pressure, it is in its normal state -- It remains active to maintain a given pressure.
When the OP valve is at its working pressure, it is not in its normal state -- It will remain active only as long as pressure exceeds the limit.
They both return unwanted pressure to the tank, but that is where the similarity ends. They don't work identically. One is in its normal state, while the other is not. One maintains pressure, while the other limits it.
If we look at normal system pressure(s), one constantly relies on its valve, while the other's valve is usually dormant.

The biggest difference in or train of thought here ( which is good by the way) is this you say the oil pump valve is designed to protect the oil seals / filter etc from over pressure, and it does do that however I say it is designed to provide the best possible lubrication. In short the Oil Pump is not designed around the seals rather the seals are designed around the Best Possible Lube. The valve in the FD and the Oil pump function on the same principal, but the PPR has a constant 100 or more psi behind it from a constant speed pump. The difference is in the pump not the function of the valves.

I didn't say the pump or valve was designed around anything. (I can see how blending purpose/design/function would make it sound that way. Are you a lawyer ;-) I said the valve's purpose is not to maintain a certain pressure, because you said that was its sole purpose in life, and I disagree. I said, "It is to limit pressure", because its function is to protect the oil system. I will say that it is the oil pump that is designed to provide the best possible lubrication ("adequate" in the real world ;-) And that the valve is designed around the maximum system pressure, in order to perform its function/purpose. You said, "if you use a stronger spring you will have higher Oil pressure", which I also disagree with. That's all I had a problem with -- I basically agree with the rest...
To me, what you first said would be like saying, "I have worked on a gazillion alternators and that thermal breaker's sole function in life is to maintain current at a given amperage. If you use a higher rated breaker you will have higher amperage." Would you buy that? I hope not.

[Giamanut]

When the PPR valve is at its working pressure, it is in its normal state -- It remains active to maintain a given pressure.
When the OP valve is at its working pressure, it is not in its normal state -- It will remain active only as long as pressure exceeds the limit.
They both return unwanted pressure to the tank, but that is where the similarity ends. They don't work identically. One is in its normal state, while the other is not. One maintains pressure, while the other limits it.
If we look at normal system pressure(s), one constantly relies on its valve, while the other's valve is usually dormant.


I didn't say the pump or valve was designed around anything. (I can see how blending purpose/design/function would make it sound that way. Are you a lawyer ;-) I said the valve's purpose is not to maintain a certain pressure, because you said that was its sole purpose in life, and I disagree. I said, "It is to limit pressure", because its function is to protect the oil system. I will say that it is the oil pump that is designed to provide the best possible lubrication ("adequate" in the real world ;-) And that the valve is designed around the maximum system pressure, in order to perform its function/purpose. You said, "if you use a stronger spring you will have higher Oil pressure", which I also disagree with. That's all I had a problem with -- I basically agree with the rest...
To me, what you first said would be like saying, "I have worked on a gazillion alternators and that thermal breaker's sole function in life is to maintain current at a given amperage. If you use a higher rated breaker you will have higher amperage." Would you buy that? I hope not.

You know who Invented copper wire?
2 Attorney's fighting over a Penny.
It's all Good.
You obviously have very good understating and I don't mean to dispute anything really, because it is pretty minor differences.
So why do so many D's peg the OP gauge when cold? No way there making 80 PSI the book specs. 65 PSI @4000 RPM so I doubt they ever see a legit 80 psi. Sending unit maybe? Thoughts?

[Parzival]

You know who Invented copper wire?
2 Attorney's fighting over a Penny.
It's all Good.
You obviously have very good understating and I don't mean to dispute anything really, because it is pretty minor differences.
So why do so many D's peg the OP gauge when cold? No way there making 80 PSI the book specs. 65 PSI @4000 RPM so I doubt they ever see a legit 80 psi. Sending unit maybe? Thoughts?

Its the sending unit, they were not correct from the factory.

[Bitsyncmaster]

So why do so many D's peg the OP gauge when cold? No way there making 80 PSI the book specs. 65 PSI @4000 RPM so I doubt they ever see a legit 80 psi. Sending unit maybe? Thoughts?

That is a good question. My guess is they do get 80 PSI when the oil is cold and the pump design lets that thick oil build more pressure.

[Ron]

You know who Invented copper wire?
2 Attorney's fighting over a Penny.
It's all Good.
You obviously have very good understating and I don't mean to dispute anything really, because it is pretty minor differences.
So why do so many D's peg the OP gauge when cold? No way there making 80 PSI the book specs. 65 PSI @4000 RPM so I doubt they ever see a legit 80 psi. Sending unit maybe? Thoughts?

LOL - Since the drawing process wasn't around back then, I wonder who got the dust when they sawed that tiny spiral...and who paid for doing it?

Agreed.

I agree with Dave, most of them are really getting 80psi. When cold, the oil is thicker and the clearances are smaller so the resistance to flow increases. A lot of people dump STP etc. into the crankcase... I wouldn't dismiss the gauges entirely though (The DeLorean electrical system in general leaves a lot to be desired.) W/O working it out, I would suspect that the many different style alternators (integrated voltage regulators), cold components and replenishing the battery after a cold start might come into play...Probably insignificant.

You can get a mechanical gauge setup with several adapters for less than $25.00 and check it out easily since the sending units are easy to get to. (Good tool to throw on the shelf ;-)

[Bertone80]

Definitely, that will help.

I used assembly lube and always primed the oil pump before firing the engine. There are different ways depending on the type of engine to do this. On my recent Magnum build, the engine builder recommended STP Oil Treatment (15 oz) along with the normal spec engine oil. Change at 1,000 miles.

I think you are saying to prime the oil pump with assembly lube. I have heard of such before but wondered how this is done. Is it by taking apart the pump (4 bolts) then fill up the space inside the pump then reassemble it? Just want to make sure it is done this way, or else.

The reason I ask is because I have been working on resealing the liners and reassembling my B28F engine of my Volvo Bertone. Hope you guys don't mind a Volvo guy kind of getting all the know-how and wisdom from the Delorean group here. I have completed the reassembling of the liners and torqued the heads down. I have also reassembled the timing chain cover and torqued the crankshaft pulley. Then I realized that I should have primed my oil pump before this last step. What a mistake!

I can loosen the pulley and remove the timing chain cover and prime the oil pump. But can it be done in a different way? There is a plug on the top of the engine located right beneath the water pump. Can I fill oil into the hole by opening up the plug (it's a large screw)? I already tried it. The oil quickly flowed into the oil filter through the center tube. So the oil did not really flow into the pump. Looks like this will not prime the pump.

Any recommendations? I hate to have to go back to tear down the timing chain cover. Thanks a lot everyone!

[Bertone80]

Here is an image of the front end behind the timing chain cover of a B28F PRV engine. You can see the plug that I am talking about actually open s up a path into the oil passage from there oil will flow up into the cylinder heads. The oil pressure sensor switch can be seen on the left side of the oil passage on the picture. I though if I could fill up the oil there the oil pump can be primed. I am not sure about it now.
B28F-01.jpg

[Bertone80]

Here is a picture that shows the plug.
B28F-02.jpg

[Ron]

"Remove the oil filter and inject some engine oil through hole (A) with an oil can to prime the oil pumps. (Fig. 111)"
Fig111.jpg

20 W 40 ABOVE -10°C (14°F)

The above is from the Workshop Manual, C:10:02, available for download in the Resources section, HERE.

FWIW- Many people like to also put oil in the filter, disable the ignition and turn the engine over until they see the pressure start to rise before 1st startup. But, not a good idea if the cams are not broke in....