Farm Equipment - Oil filters & Oil Pressure

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Oil filters & Oil Pressure

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Category: Allis Chalmers
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URL: https://www.allischalmers.com/forum/forum_posts.asp?TID=175691
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Topic: Oil filters & Oil Pressure

Posted By: Longmire
Subject: Oil filters & Oil Pressure
Date Posted: 03 Nov 2020 at 11:43am

Greetings! I'm new to this site and thought I would pose a question to the wise minds in this forum.
I know this topic has been discussed thoroughly in the past but thought I would pose this observation I recently came across during an oil change on my 49 WD.
The oil pressure on this engine has always carried in the R & M range of the gauge at cold crank and start/idle. During this maint. interval I purchased a Baldwin T-300M oil filter vrs the AutoZone/Carquest 84011 filter previously used. After the oil change and compression testing I noticed my cranking oil pressure would struggle to get to the N on the gauge. My curiosity told me to put the Carquest filter back on and run test again. This time the cranking pressure climbed back to the R-M range. I just ordered another 84011 filter and will repeat the test.
Observation of the rocker shaft oiling indicates go flow from the rocker arm oil passage throughout the entire shaft during cranking.
My suspicion tells me based on the gauge location on the filter housing that the 84011 may be more restrictive than the T-300M filter thus causing more back pressure on the gauge.
I've run this test twice with the same results. The only reason I bring this subject back up is because I've read where there were issues with lower pressure from some of the various filter manufacturing. I've confirmed that both filters appear to have the cotton filler (only visual not cut open).
The other thought to this test is that possibly the regulator valve is opening up during the test with the 84011 filter. This is the same thought from some of my wrenchhead buds. If this is the case then the 84011 filter has more restriction.
Inquiring minds are interested in your thoughts please. Carl

Replies:

Posted By: Jim.ME
Date Posted: 03 Nov 2020 at 3:09pm

There is some difference in how tightly different filters are packed. There can also be a difference between a used filter and new one. I often see a bit lower pressure with a new filter of the same brand.

Posted By: steve(ill)
Date Posted: 03 Nov 2020 at 4:19pm

I would not worry much about the cranking pressure. You should have a MAX of about 15 psi when running at higher throttle ( over 1000 RPM).... You would like to see a MIN of 5 psi at idle.. Of course 10- 15 would be GREAT !... You can change the pressure slightly with different manufactures of the filter, as you mentioned... and also by useing a higher viscosity oil .... Cooler winter startups would also give more initial pressure than summer..... it all depends on how much oil you can push thru that little tube in the center of the filter, back to sump.. That is the "LOST pressure".

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Like them all, but love the "B"s.

Posted By: Bill_MN
Date Posted: 03 Nov 2020 at 4:22pm

You say you are only getting to the N during cranking with the new one, that is still normal and more than enough to run these engines. Have you actually started it? You are comparing apples to oranges with a new vs. used filter, run it and let the new filter get fully saturated then see where you're at. These bypass systems are different, you will have less pressure with a new filter initially because it is cleaner and less restricted. Keep the Baldwin on it, it's a good filter.

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1951 WD #78283, 1918 Case 28x50 Thresher #76738, Case Centennial B 2x16 Plow

Posted By: garden_guy
Date Posted: 03 Nov 2020 at 4:38pm

I have a new Baldwin T-300M filter ready to install on my WDs next season, and am replacing an old Deutz Allis filter on one and an old Carquest filter on the other... Curious to see the discussion on these filters.

Posted By: Longmire
Date Posted: 03 Nov 2020 at 7:26pm

Appreciate all the responses on this discussion. Makes perfect sense what everyone is saying here about these older oil pressure systems and this packing in these filters. I'll fire it up with the Baldwin and see how the pressure responds after the saturation period. Thanks again on all your insight. Carl