Can change from copper to nylon oil line affect pressure?

[Charles P.]

I just finished replacing the oil pressure line, due to a leak, on a 73 SB. I believe it had at some point been changed to copper.
The pressures with the copper line were always above 35 pounds. Now with the new nylon line installed the pressure reading is significantly under at approximately 25 to 30 while idling.

Could the lumen size or length of the line affect the pressure reading? Also I did not prime the line reading here it was not necessary.

I have checked the line for leaks and don't see any. Also the needle is not bouncing which might indicate a leak

Anyone familiar with this?

[Cathy S.]

Re: Can change from copper to nylon oil line affect pressure?

Not if it's the same I.O.

[Terry M.]

Re: Can change from copper to nylon oil line affect pressure?

Jack Humphrey will tell us whose law it is, but in a closed container the pressure is equal on all parts of the container. I can still remember the drawing with arrows pointing toward all the surfaces of a cylinder from my high school Physics book. The diameter of the line makes no difference to the pressure. A smaller diameter line may dampen the response of the gauge to changes in pressure -- that is the needle will rise or fall more slowly if the inside diameter of the line is very small, but that is the dynamic response and not a steady reading like one would find at idle.

[Michael W.]

Re: Can change from copper to nylon oil line affect pressure?

The length, diameter, routing, material or contents of the line will make no difference. If 35 psi goes in, 35 psi comes out. Numerous laws of physics and hydraulics apply.

[Larry M.]

Re: Can change from copper to nylon oil line affect pressure?

Pressure should (will) be the same.

The nylon tubing has brass or steel ferrules that keep the tubing from collapsing or restricting. Did you use these during your installation??

Larry

[Charles P.]

Re: Can change from copper to nylon oil line affect pressure?

The length, diameter, routing, material or contents of the line will make no difference. If 35 psi goes in, 35 psi comes out. Numerous laws of physics and hydraulics apply.

I guess we can tell the physicians to take a flying leap when they prescribe vasodilators to lower blood pressure then!

[Charles P.]

Re: Can change from copper to nylon oil line affect pressure?

Larry--I just replaced the line with a backup and all is well. Could have been a restriction somewhere. The tapered? ferrules looked intact. Thanks

[Jim D.]

Re: Can change from copper to nylon oil line affect pressure?

I guess we can tell the physicians to take a flying leap when they prescribe vasodilators to lower blood pressure then!

You're confusing STATIC and RESIDUAL pressures.

[Michael W.]

Re: Can change from copper to nylon oil line affect pressure?

You're confusing STATIC and RESIDUAL pressures.

Exactly.