Recent Topics
02' Silverado 5.3L Differential gasket
by Gito
07/23/18 10:46 AM
Changed the oil in the Taurus on Saturday
by redhat
07/23/18 10:45 AM
Good Porcelain Wet Saw Blade Suggestions
by ssamaroo01
07/23/18 10:25 AM
2012 suburban steering joint problem
by jstutz
07/23/18 10:12 AM
Corelle brand dish exploded
by sprite1741
07/23/18 09:40 AM
Hemi Tick
by dawgn86
07/23/18 09:25 AM
Zoro Promo Code
by Zee09
07/23/18 09:22 AM
Smell after Car Shuts off
by mbacfp
07/23/18 09:19 AM
Gumout High Mileage Fuel Injector Cleaner
by 2015_PSD
07/23/18 09:00 AM
Oshkosh ATC on youtube
by Oldmoparguy1
07/23/18 08:43 AM
Appropriate HTHS & KV100 In An Oil You Will Run ?
by ChrisD46
07/23/18 08:11 AM
What is your favorite brake pad material?
by ZZman
07/23/18 07:51 AM
Office 2016 Desktop vs. Office 365
by doitmyself
07/23/18 07:34 AM
Progressice Snapshot
by Duffyjr
07/23/18 06:51 AM
Ford TPMS 19 tool
by Black_Thunder
07/23/18 03:57 AM
If Tradies Owned a Pub
by SR5
07/23/18 02:44 AM
Sister call the number
by WhyMe
07/23/18 01:44 AM
Low oil pressure at idle
by Spetz
07/22/18 11:43 PM
Buy an extended warranty on HF Pressure washer?
by David2431
07/22/18 11:21 PM
2009 Matrix Bosal muffler
by expat
07/22/18 10:58 PM
Newest Members
UN1203, Cerivera, motogp46, Kyle0651, cavisco
65536 Registered Users
Who's Online
96 registered (2James1, 330indy, 2009Edge, 10ecfarmer, 2012AccentSE, 10 invisible), 1593 Guests and 39 Spiders online.
Key: Admin, Global Mod, Mod
Forum Stats
65536 Members
67 Forums
287517 Topics
4796327 Posts

Max Online: 3590 @ 01/24/17 08:07 PM
Donate to BITOG
Topic Options
#4584043 - 11/24/17 09:19 PM Oil Filter Effect on Pressure
bunnspecial Offline


Registered: 11/23/15
Posts: 785
Loc: US
When I bought my MG, it had a Fram Ultra-Guard on it and ran 40-45 psi at warm idle. Since then, out of preference, I've been running a Motorcraft FL-300 and managed the same oil pressure.

I changed the oil today, but opted for the larger FL-1A filter this time around. I'm still using the same oil as what I drained-VR-1 20W-50 but I'm now seeing 65psi at warm idle and the engine will bounce off the oil pressure relief valve(75 psi) at speed.

If anything, I'd expect the larger FL-1A to give me lower pressure than the FL-300. The FL-1A was bought new from the local Ford dealer on Wednesday. The removed FL-300 was bought some time in the fall of 2016.

Has there been some other change in Motorcraft filters that would have led to this?
_________________________
2010 Lincoln MKZ-Mobil 1 5W-30
1970 MG MGB Roadster-Valvoline VR-1 20W-50

Top
#4584054 - 11/24/17 09:29 PM Re: Oil Filter Effect on Pressure [Re: bunnspecial]
2009Edge Online   content


Registered: 06/10/09
Posts: 256
Loc: Texas
Larger filter
more media
more surface area for filtration
lower differential pressure.

Top
#4584076 - 11/24/17 09:53 PM Re: Oil Filter Effect on Pressure [Re: bunnspecial]
ZeeOSix Offline


Registered: 07/22/10
Posts: 17934
Loc: PNW
An oil filter is not going to effect the idle oil pressure because the positive displacement oil pump is not in pressure relief. Your old oil was probably thinned down and diluted from use, and the new oil was thicker than the old, thereby giving you higher idle oil pressure and also causing the pump to hit pressure relief. Only time oil filter A vs oil filter B (if one was more restrictive than the other) would affect the oil pressure (with sensor after the filter) is at high engine RPM when the oil pump goes in to pressure relief.

Top
#4584147 - 11/25/17 02:53 AM Re: Oil Filter Effect on Pressure [Re: bunnspecial]
Johnny2Bad Offline


Registered: 05/20/13
Posts: 1927
Loc: Saskatchewan, Canada
The more restrictive the filter, the lower the Oil Pressure after the filter, and vice versa. Perfectly normal, but it illustrates why OEMs don't use filters with very low size particle entrapment.

This might seem counter-intuitive, but if you place a pressure gauge on each side of a filter you can read the pressure drop directly. Pressure is also related to flow rate; a high flow will lower pressure and vice versa. So it's possible to manage the pressure by manipulating the two (filter beta and oil flow).

Having said all that, it's extremely unusual to have drastic changes in pressure with just a filter change ... fairly large differences in filter restriction have little effect normally. So perhaps your experience is somewhat unusual.
_________________________
'57 FL Straight 50 wt
'90 Miata 1.8L w/Rotrex Supercharger [Mobil1 0W-40]
'96 Ram 1500 [3.7L Mobil1 0W-20 / 1L 15W-50]
'01 PT Cruiser [Mobil1 0W-40]

Top
#4584166 - 11/25/17 04:55 AM Re: Oil Filter Effect on Pressure [Re: Johnny2Bad]
ZeeOSix Offline


Registered: 07/22/10
Posts: 17934
Loc: PNW
Originally Posted By: Johnny2Bad
The more restrictive the filter, the lower the Oil Pressure after the filter, and vice versa.


Not true with a positive displacement oil pump unless the pump is in pressure relief.

Pump pressure relief usually only happens at high engine RPM when the oil is cold. After the oil is fully hot (200+ F) the pump will typically not hit pressure relief unless a much heavier than specified oil is being used.

Top
#4584211 - 11/25/17 07:03 AM Re: Oil Filter Effect on Pressure [Re: bunnspecial]
dnewton3 Offline



Registered: 05/14/07
Posts: 7410
Loc: Indianapolis, IN
There is always a little bit of dP across the filter media, but Zee is right; it's minimal for sure. The greatest dP is the lube circuit itself.
See Jim Allen's data from his thread testing dP.
How many times do we have to go over this? (sigh ......)

Consider worst case conditions ...
the dP across media is high, and the filter BP opens. So what?
Seriously, who the heck cares?
If it's common (happens all the time), then where's the proof that this is descrutive? Where are all the dead engines at the side of the road?
Conversely, if this is rare (which data shows it is), then why worry over something that is a minimal event?

Either way, when someone comes forth with credible data directly showing correlation thus linking the dP/BP events to dead engines, I'll give a darn.
Until then, this is typical BITOG hysteria over nothing.




Edited by dnewton3 (11/25/17 07:12 AM)
_________________________
The act of preventative maintenance, in and of itself, is FAR MORE important than brand/grade/base choices among lubes and filters.
- under maintaining something is akin to abuse/neglect; that can kill equipment by shortening the lifespan
- over maintaining something has never been proven to be anything but a waste of time and money

Top
#4584290 - 11/25/17 08:23 AM Re: Oil Filter Effect on Pressure [Re: bunnspecial]
bullwinkle Online   confused


Registered: 10/09/04
Posts: 7744
Loc: Cincinnati, OH, USA
I didn't see what weight oil you were using? As mentioned above, likely your old oil was fuel diluted somewhat, maybe sheared, causing viscosity loss. My 6.2 diesel GMC is kind of my filter test bed-it gets 10W30 synthetic blend (T5) in winter, whatever 15W40 I have laying around in summer, and it will bounce off the relief (around 70 PSI) on cold starts, if it's cold enough, no matter what's in the crankcase-UNTIL it warms up, or the oil has 3K or more miles-then it won't go above 50 PSI, and it's done the same with whatever filter is on it, from cheap Puro Classics to Fram Ultras.
_________________________
06 Ram 3500 CTD 4X4(FG Venturi), 93 GMC C3500 6.2, 89 F-450 7.3, 98 XJ 4.0(XG8A), 05 xB(XG3600), 15 Transit 3.7, 03 Merc Grand Marquis 4.6 2V(XG2)

Top
#4584383 - 11/25/17 10:38 AM Re: Oil Filter Effect on Pressure [Re: bunnspecial]
bunnspecial Offline


Registered: 11/23/15
Posts: 785
Loc: US
As I said in the opening post, the oil is VR-1 20W-50.

I have NEVER seen pressure this high in this engine, even with a fresh change.
_________________________
2010 Lincoln MKZ-Mobil 1 5W-30
1970 MG MGB Roadster-Valvoline VR-1 20W-50

Top
#4584446 - 11/25/17 12:06 PM Re: Oil Filter Effect on Pressure [Re: dnewton3]
Linctex Offline


Registered: 12/31/16
Posts: 6186
Loc: Waco, TX
Originally Posted By: dnewton3

See Jim Allen's data from his thread testing dP.
How many times do we have to go over this? (sigh ......)


https://bobistheoilguy.com/forums/ubbthreads.php/topics/3197094
_________________________
"The evidence demands a verdict".
(Re:VOA)"it's nearly impossible to actually know the particular additives that are in there at what concentrations."

Top
#4584478 - 11/25/17 12:49 PM Re: Oil Filter Effect on Pressure [Re: bunnspecial]
ZeeOSix Offline


Registered: 07/22/10
Posts: 17934
Loc: PNW
Originally Posted By: bunnspecial
When I bought my MG ...

Do you know for sure if the oil pressure sensor is located before or after the filter?

If the sensor is located before the filter, then you would see the oil pressure change due to the filter's flow restriction.

If the sensor is located after the filter then the oil pressure will not be affected by the filter unless the positive displacement oil pump is in pressure relief, which happens rarely as mentioned earlier - ie, very thick oil and high engine RPM.

Top
#4584516 - 11/25/17 01:30 PM Re: Oil Filter Effect on Pressure [Re: ZeeOSix]
bunnspecial Offline


Registered: 11/23/15
Posts: 785
Loc: US
Originally Posted By: ZeeOSix
Originally Posted By: bunnspecial
When I bought my MG ...

Do you know for sure if the oil pressure sensor is located before or after the filter?

If the sensor is located before the filter, then you would see the oil pressure change due to the filter's flow restriction.

If the sensor is located after the filter then the oil pressure will not be affected by the filter unless the positive displacement oil pump is in pressure relief, which happens rarely as mentioned earlier - ie, very thick oil and high engine RPM.


That honestly is something I should know but don't. The take-off for either the mechanical gauge(62-67, 73-80) or electric gauge sender(68-72) is located right next to the rear oil cooler take off. That is located just BEHIND the distributor, which should be just in line with the oil pump out.

I have a block in the storage building that I'm planning on having machined this winter so I can start assembling it for my MGA. I'll try to look at it and see if I can figure it out if I can't find the answer elsewhere.
_________________________
2010 Lincoln MKZ-Mobil 1 5W-30
1970 MG MGB Roadster-Valvoline VR-1 20W-50

Top