The Ford Barn

01-01-1970, 12:00 AM

Step 1: checked oil pressure from port @ rear of engine with mechanical gauge=60psi

Step 2: installed by pass oil filter lines with .040" restrictor, checked oil pressure downsteam from restrictor=20psi

Question: Is the psi reading being affected by the restrictor? I should mention that the restrictor dumps into a TEE: left side dumps into oil filter canister, right side goes to the gauge. My thought is to put a gauge into the line upstream from restictor to check pressure just to be sure. A 40psi difference is worth checking into. Thanks much for any thoughts.

03-28-2005, 06:44 PM

The pressure at the tee on the non restricted side is the normal place to sense the oil pressure.

The restrictor passes such a small amount of oil to the oil filter in relation to the output of the oil pump it should not make much difference.

The 40 psi difference between the supply side of the restrictor and the filter side really don't matter as the oil in the filter just goes back to the oil pan any way.

If you are getting 60 psi at idle at normal operating temperature it sounds like a lot to me.

At normal a operating temperature at idle around 20 psi is about normal.

Newton

03-28-2005, 10:47 PM

20 lbs. is fine. ken ct.

03-29-2005, 10:06 AM

The oil filter circuit dumps into the pan through an open line, and is essentially a leak in the main circuit. There is high pressure before the restrictor because the restrictor cuts flow through the line to way less than is available. On the other side, the oil coming to the filter is restricted only by the filter element and the open steel line to the hole in the pan, which have more flow capacity than the restrictor, so pressure drops. If you measured on the OUT side of the filter, you'd probably get close to zero. Actually, the engine's total oil pressure in the main passages is also based on leakage rates--the oil is at high pressure because the pump is trying to stuff in more oil than can leak out around the edges of the bearings! The maximum pressure possible is governed by the oil pressure relief valve, which just adds a big leak when max pressure is passed.

03-29-2005, 06:37 PM

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Thanks, so it's not something to worry about. I didn't think so , but wanted to be sure.

01-01-1970, 12:00 AM	#1
Guest Posts: n/a	Oil pressure question Step 1: checked oil pressure from port @ rear of engine with mechanical gauge=60psi Step 2: installed by pass oil filter lines with .040" restrictor, checked oil pressure downsteam from restrictor=20psi Question: Is the psi reading being affected by the restrictor? I should mention that the restrictor dumps into a TEE: left side dumps into oil filter canister, right side goes to the gauge. My thought is to put a gauge into the line upstream from restictor to check pressure just to be sure. A 40psi difference is worth checking into. Thanks much for any thoughts.

03-28-2005, 06:44 PM	#2
Guest Posts: n/a	Re: Oil pressure question The pressure at the tee on the non restricted side is the normal place to sense the oil pressure. The restrictor passes such a small amount of oil to the oil filter in relation to the output of the oil pump it should not make much difference. The 40 psi difference between the supply side of the restrictor and the filter side really don't matter as the oil in the filter just goes back to the oil pan any way. If you are getting 60 psi at idle at normal operating temperature it sounds like a lot to me. At normal a operating temperature at idle around 20 psi is about normal. Newton

03-28-2005, 10:47 PM	#3
Guest Posts: n/a	Re: Oil pressure question 20 lbs. is fine. ken ct.

03-29-2005, 10:06 AM	#4
Guest Posts: n/a	Re: Oil pressure question The oil filter circuit dumps into the pan through an open line, and is essentially a leak in the main circuit. There is high pressure before the restrictor because the restrictor cuts flow through the line to way less than is available. On the other side, the oil coming to the filter is restricted only by the filter element and the open steel line to the hole in the pan, which have more flow capacity than the restrictor, so pressure drops. If you measured on the OUT side of the filter, you'd probably get close to zero. Actually, the engine's total oil pressure in the main passages is also based on leakage rates--the oil is at high pressure because the pump is trying to stuff in more oil than can leak out around the edges of the bearings! The maximum pressure possible is governed by the oil pressure relief valve, which just adds a big leak when max pressure is passed.

03-29-2005, 06:37 PM	#5
Guest Posts: n/a	Re: Oil pressure question Sponsored Links (Register now to hide all advertisements) Thanks, so it's not something to worry about. I didn't think so , but wanted to be sure.