Port for oil pressure

[coach]

Hello Guys,
I am putting an oil pressure gauge in my console gauge pod. I am running the line up into the tranny tunnel where I drilled my hole for my aftermarket shifter cable to come thru. Is there a place on the rear of the block to get a good reading? I have enough room in the grommet to run the line there.

Thanks
Coach

 

[LOT]

no

Nothing on the back of block that you can do anything with @ this point. If you have the eng. out--yes. IMO the best place to get it now is to add a T @ the oil pressure sending unit.--- Lee Thompson

 

[coach]

Thanks Lee,
Starting over with new I.D.??? Hows Kentucky???

Thanks for all your help and I wish you would have gotten to build a motor for me. This damn economy messed that up. Well at least I made you some oil plates.

Thanks
Donnie

 

[charlief1]

The front location is the best for oiling Coach. If you want to know the difference between the best and worst in the engine you can tap off the block in the back to check it so you know if you have a pressure problem but don't use the back of the block for your main pressure readings.

 

[Boost231]

here is the best picture i can come up with.

This is how i did mine. Not super clean but it works.

 

[LOT]

???

The front location is the best for oiling Coach. If you want to know the difference between the best and worst in the engine you can tap off the block in the back to check it so you know if you have a pressure problem but don't use the back of the block for your main pressure readings.

And why would you not want to come off the back of block for your main pressure reading?

 

[dr_frankenstein]

yea explain this one to me too charlie...

I have always taken my readings off the back of the block.... i prefer to know pressure after it has passed to cam and rods.... seems more accurate.

A.j.

 

[charlief1]

The lowest point of pressure is on the drivers side rear. If you want to know how low the pressure really is when the engine is running that's the place you need to tap into. The main gallery on the passenger side has to go through several turns before it gets to the main galley so by the time it gets there you loose about 30-35 pounds of pressure. If I remember right, each 90 degree turn looses 10 pounds of pressure.

 

[LOT]

Wrong and wrong again

The lowest point of pressure is on the drivers side rear. If you want to know how low the pressure really is when the engine is running that's the place you need to tap into. The main gallery on the passenger side has to go through several turns before it gets to the main galley so by the time it gets there you loose about 30-35 pounds of pressure. If I remember right, each 90 degree turn looses 10 pounds of pressure.

I will agree with you that if getting it off the rear to use the passenger side (only reason I say this is because the front cam bearing could wreck havoc with the reading).
If you place a gage @ the front (sending unit area) and one @ the rear galley opening passenger side they will read the same assuming gages are accurate. Jim Ruggles and I talked about this years ago and I placed gages @ both places to see for my self--no difference in pressure. To make the test true I switched gages--same pressure reading @ both ports with eng. running and HOT--rev the eng. and both gages read the same.Also if each 90 degree bend lost 10 psi then the guys with 20 psi @ hot idle ( reading of the pump area) would have negative oil pressure @ the bearings. I have had this argument more than once in the past and I know what I'm talking about.
If anyone don't believe me I can give more info. Tired of typing now.--Lee

 

[coach]

I agree with Lee. A pressurized system is a constant no matter how many turns or hills or whatever. That is like saying your air line looses 10 lbs of pressure for every bend in the hose. The velocity of the oil might change at a 90 dgr bend, but not the pressure. The size of the passages would affect pressure, but they should be all the same. Any engineer knows that, so I would assume these blocks have the same size passages throughout the entire system.

Thanks
Coach

 

[LOT]

Not an engineer but

I agree with Lee. A pressurized system is a constant no matter how many turns or hills or whatever. That is like saying your air line looses 10 lbs of pressure for every bend in the hose. The velocity of the oil might change at a 90 dgr bend, but not the pressure. The size of the passages would affect pressure, but they should be all the same. Any engineer knows that, so I would assume these blocks have the same size passages throughout the entire system.

Thanks
Coach

Exactly what I was trying to say---The only reason the pressure would be less @ the bearing as compared to @ the pump would be if it passed through an orfice that would not flow enough oil to supply the loss @ the bearings. There is no such restriction in the eng. Not built in anyway--maybe with some foreign materail but in that case you would have major problems. Bearing clearance is a controlled oil leak-- assuming all bearings had .003 clearance--that is 10 X .003--not enough loss that a .500 supply line can;t satisfy. If there is any difference in pressure @ the bearing as compare to @ the pump it will not be detected with the gages we use.

 

[Robert Wilson]

I have had the same gauge plumbed to the front and back of my engine and did not notice any discernable difference in pressure.

 

[charlief1]

I was going off of the Buick Power Source and info my dad told me. He was an engineer and delt with hydrology issues all the time. If it's incorrect it's been a very long time since he told me the info. He died in June of 90 and I think it was mid 80's when we talked about it.

 

[gnxtc2]

Now since on the subject of volume and pressure.

If you take an oil pump that very efficient and supplies volume do you still need to run high pressure?

As a crankshaft is spinning, there is hydrodynamic wedge of oil between the "bearing" and crank. As the crank is spinning, it's forming a vacuum effect on the oil.

We all know that when there is pressure, there is heat build up. Now with all the heat, the bearing clearance change

Billy T.
gnxtc2@aol.com

 

[Blazer406]

Now since on the subject of volume and pressure.

If you take an oil pump that very efficient and supplies volume do you still need to run high pressure?

As a crankshaft is spinning, there is hydrodynamic wedge of oil between the "bearing" and crank. As the crank is spinning, it's forming a vacuum effect on the oil.

We all know that when there is pressure, there is heat build up. Now with all the heat, the bearing clearance change

Billy T.
gnxtc2@aol.com

Billy,

IMHO.... yes.... you need the pressure. Volume is good.... that is why race motors are built loose IMHO..... so the volume will be greater thru each bearing therefore providing the cooling effect.

Pressure is also needed..... as HP numbers go much higher.... and/or engines run more RPM's...... the load on the crank journals increase exponentially..... and to keep that hydrodynamic wedge in place..... not allowing metal to metal contact....... you need increased pressures. It becomes somewhat a math problem........higher loads need higher pressures....and higher rpm's and loads.... heat the bearings.... requiring an increased volume flow through the bearing.... to keep it cool.

The above info is my own opinion.... but is based on mechanical engineering principles.... you guys feel free to critique as needed.