Why would oil pressure go up when you reduce exhaust back pressure? I just hollowed out my cat conv and put a short muffler and exited in front of the rear wheel greatly reducing flow restriction. My oil pressure went from 25 psi at 2k rpm to 37. What do you think? 1990 ford f250 5.8l
OIl pressure and exhaust back pressure
- Thread starter liberty
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Same operating temperature? I don't know why it would make a difference there.
I dont see any immediate correlation. I will think about it though...
Originally Posted By: JRed
Your oil pressure gauge/sender is probably flaking out for some reason.
+1
Maybe a corroded or loose wire. Gauges can "Fail High" OR "Fail low."
If taking out gauge, make sure its wired up correctly sometimes Gauges and senders need changed. Sometimes.
Knew someone w a 2003 Tahoe, Oil Pressure was showing as 120Psi all the time. Gauge "Failed High."
Now, another car, its indicating higher than normal pressures, but it could be anything. Gauges, engine, no worry at all, actual OP.. Any of the above. Its still within operating range, so it will only be touched as part of Dash re-wiring/cleaning/wiring clusters.
Your oil pressure gauge/sender is probably flaking out for some reason.
+1
Maybe a corroded or loose wire. Gauges can "Fail High" OR "Fail low."
If taking out gauge, make sure its wired up correctly sometimes Gauges and senders need changed. Sometimes.
Knew someone w a 2003 Tahoe, Oil Pressure was showing as 120Psi all the time. Gauge "Failed High."
Now, another car, its indicating higher than normal pressures, but it could be anything. Gauges, engine, no worry at all, actual OP.. Any of the above. Its still within operating range, so it will only be touched as part of Dash re-wiring/cleaning/wiring clusters.
It is a Sun Pro mechanical guage that works perfectly. How do I know this? It is brand new. Just installed before the exhaust to monitor a low oil pressure condition. I am running Mobil One 15w50 to maintain adequate pressure. I always had 25 psi hot at 2k rpm. I am now getting 37 psi.
I too, do not see the correlation between the said 2.
Remember: there's no direct link between the 2 (oil is running/lubricating inside your engine moving parts, exhaust gas only gets handled through combustion chamber+ valves + exhaust piping , resonators and cats, and they (between oil/oil pressure and exhaust gas generation + routing) do not come into any form of contact.
I'm with ARCOGraphite on this one.
Q.
Remember: there's no direct link between the 2 (oil is running/lubricating inside your engine moving parts, exhaust gas only gets handled through combustion chamber+ valves + exhaust piping , resonators and cats, and they (between oil/oil pressure and exhaust gas generation + routing) do not come into any form of contact.
I'm with ARCOGraphite on this one.
Q.
Originally Posted By: liberty
It is a Sun Pro mechanical guage that works perfectly. How do I know this? It is brand new. Just installed before the exhaust to monitor a low oil pressure condition. I am running Mobil One 15w50 to maintain adequate pressure. I always had 25 psi hot at 2k rpm. I am now getting 37 psi.
That is great that the great oil M1 15W-50 sounds like it will give more Oil pressure, but the only thing i can think of is blown Head Gasket. That DOES Make pressures including Oil pressure go up.
How are you measuring Exhaust Back Pressure? Didnt know it could be.
Big engine too!
Are all your Cylinders firing? Not trying to joke.. there must be -something- going on, and unless something is amiss, like its getting into another area (blown something?) then yeah the issue might be elsewhere.
Is your IMG Intake Manifold Gasket ok? Has to be -something.- .. Vacuum?
HTH
It is a Sun Pro mechanical guage that works perfectly. How do I know this? It is brand new. Just installed before the exhaust to monitor a low oil pressure condition. I am running Mobil One 15w50 to maintain adequate pressure. I always had 25 psi hot at 2k rpm. I am now getting 37 psi.
That is great that the great oil M1 15W-50 sounds like it will give more Oil pressure, but the only thing i can think of is blown Head Gasket. That DOES Make pressures including Oil pressure go up.
How are you measuring Exhaust Back Pressure? Didnt know it could be.
Big engine too!
Are all your Cylinders firing? Not trying to joke.. there must be -something- going on, and unless something is amiss, like its getting into another area (blown something?) then yeah the issue might be elsewhere.
Is your IMG Intake Manifold Gasket ok? Has to be -something.- .. Vacuum?
HTH
Stuff something removable but constrictive into your exaust pipe and re-test.
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Originally Posted By: HangerHarley
Originally Posted By: liberty
It is a Sun Pro mechanical guage that works perfectly. How do I know this? It is brand new. Just installed before the exhaust to monitor a low oil pressure condition. I am running Mobil One 15w50 to maintain adequate pressure. I always had 25 psi hot at 2k rpm. I am now getting 37 psi.
That is great that the great oil M1 15W-50 sounds like it will give more Oil pressure, but the only thing i can think of is blown Head Gasket. That DOES Make pressures including Oil pressure go up.
How are you measuring Exhaust Back Pressure? Didnt know it could be.
Big engine too!
Are all your Cylinders firing? Not trying to joke.. there must be -something- going on, and unless something is amiss, like its getting into another area (blown something?) then yeah the issue might be elsewhere.
Is your IMG Intake Manifold Gasket ok? Has to be -something.- .. Vacuum?
HTH
How in the ***** is a blown head gasket going to increase oil pressure???????? There is NO connection between any of the cylinders and the oil galleries.
Originally Posted By: liberty
It is a Sun Pro mechanical guage that works perfectly. How do I know this? It is brand new. Just installed before the exhaust to monitor a low oil pressure condition. I am running Mobil One 15w50 to maintain adequate pressure. I always had 25 psi hot at 2k rpm. I am now getting 37 psi.
That is great that the great oil M1 15W-50 sounds like it will give more Oil pressure, but the only thing i can think of is blown Head Gasket. That DOES Make pressures including Oil pressure go up.
How are you measuring Exhaust Back Pressure? Didnt know it could be.
Big engine too!
Are all your Cylinders firing? Not trying to joke.. there must be -something- going on, and unless something is amiss, like its getting into another area (blown something?) then yeah the issue might be elsewhere.
Is your IMG Intake Manifold Gasket ok? Has to be -something.- .. Vacuum?
HTH
How in the ***** is a blown head gasket going to increase oil pressure???????? There is NO connection between any of the cylinders and the oil galleries.
1. Your engine cooled off while you were hollowing out the cat. When you started it back up the oil was thicker, hense the higher pressure (trick question answer)
2. Your partially plugged cat was causing your engine to run hotter, thereby thinning the oil and causing the lower pressure. Unplugging the cat caused your engine to run cooler and achieve normalized pressure (non trick question answer).
2. Your partially plugged cat was causing your engine to run hotter, thereby thinning the oil and causing the lower pressure. Unplugging the cat caused your engine to run cooler and achieve normalized pressure (non trick question answer).
Sounds plausible. Hot pistons = hot oil. Now about that 50 weight oil in a water cooled engine?!
i have said this before, so please dont get mad. when useing a mechanical guage, DONT use a copper, or nylon tubing. i found if dont steel breake line tubing i have trouble. it only took one time to find out that cooper or nylon WILL cause trouble. i found its a little harder to install, but well worth the work.
OVERKILL
$100 Site Donor 2021
Originally Posted By: morris
i have said this before, so please dont get mad. when useing a mechanical guage, DONT use a copper, or nylon tubing. i found if dont steel breake line tubing i have trouble. it only took one time to find out that cooper or nylon WILL cause trouble. i found its a little harder to install, but well worth the work.
I had an exciting adventure with Nylon (never had a problem with copper however). Nothing like having your heater box fill with Mobil 1. That was fun.
i have said this before, so please dont get mad. when useing a mechanical guage, DONT use a copper, or nylon tubing. i found if dont steel breake line tubing i have trouble. it only took one time to find out that cooper or nylon WILL cause trouble. i found its a little harder to install, but well worth the work.
I had an exciting adventure with Nylon (never had a problem with copper however). Nothing like having your heater box fill with Mobil 1. That was fun.
Originally Posted By: OVERK1LL
How in the ***** is a blown head gasket going to increase oil pressure????????
Glad some one else questioned that theory!
How in the ***** is a blown head gasket going to increase oil pressure????????
Glad some one else questioned that theory!
Originally Posted By: liberty
Why would oil pressure go up when you reduce exhaust back pressure? I just hollowed out my cat conv and put a short muffler and exited in front of the rear wheel greatly reducing flow restriction. My oil pressure went from 25 psi at 2k rpm to 37. What do you think? 1990 ford f250 5.8l
Did the idle RPM increase? That would account for higher oil pressure.
Why would oil pressure go up when you reduce exhaust back pressure? I just hollowed out my cat conv and put a short muffler and exited in front of the rear wheel greatly reducing flow restriction. My oil pressure went from 25 psi at 2k rpm to 37. What do you think? 1990 ford f250 5.8l
Did the idle RPM increase? That would account for higher oil pressure.
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