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Model B Oil Pressure
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Morgan in AR View Drop Down
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Joined: 25 Mar 2010
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Points: 54 		Post Options Post Options   Thanks (0) Thanks(0)   Quote Morgan in AR Quote  Post ReplyReply Direct Link To This Post Posted: 05 Aug 2016 at 6:33pm
Creston, keep us updated. I just overhauled a CA, and I have the same problem.
If we loose freedom here there is no place left to escape to. This is the last stand on earth. -Ronald Reagan
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CrestonM View Drop Down
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Points: 8391 		Post Options Post Options   Thanks (0) Thanks(0)   Quote CrestonM Quote  Post ReplyReply Direct Link To This Post Posted: 05 Aug 2016 at 7:30pm
Will do. I'm thinking since I'm going to be really busy and maybe only home every other weekend or so, I may find a good pump and swap them. If it helps, great!! If it doesn't....well....I don't know...
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49clipper View Drop Down
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Points: 7 		Post Options Post Options   Thanks (0) Thanks(0)   Quote 49clipper Quote  Post ReplyReply Direct Link To This Post Posted: 22 Mar 2024 at 11:57am
Interesting forum.   I did not have an issue with the oil pump leaking down until I changed oil to 10-30W.  Now the freshly rebuilt pump leaks down and will not show external oil pressure until primed.   I prime by removing the filter and using a small oil can pump into the port where the vertical tube goes and pump three or four times.   Quickly reinstall tube and filter and then I get oil pressure after about 15 seconds.  Now why.   apparently the external 1/4" tube leading out of the oil pump is bleeding oil back down that tube.   Why???   I made a fixture when I rebuilt the pump to measure the clearance between the cover plate and the rotor.   My manual says it has to be .00" or less.   I got mine down to .001" by using two .005" gaskets in the kit and dressing the cover down.  My new rotor sits proud of the pump housing by about .007-8" thousandths, just like the old one.  I see how the system works, but looking for the answer to this riddle.  From what I see, the filter cannot affect oil pressure.  the oil is pumped up the tube and gravity feeds the filter media and then just drains back into the case.  the line to the guage is just measuring the oil that gets dripped into the filter.  Its free flow.   Someone mentioned a Wix filter.   How is that different?
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steve(ill) View Drop Down
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Points: 81414 		Post Options Post Options   Thanks (0) Thanks(0)   Quote steve(ill) Quote  Post ReplyReply Direct Link To This Post Posted: 22 Mar 2024 at 1:02pm
The filter material is PACKED COTTON... It does cause a few psi backpressure to the syste. YEs there is a 1/4 inch tube with a 1/8 inch orifice inside the filter housing that is doing MOST of the restriction, but the filter  helps.  20 years ago WIX made filters with paper material instead of PACKED COTTON and they lost pressure due to that.

If your system drains back to sump, then you possibly have an air leak.. Look for a damp spot on the 1/8 inch pipe out of the bell housing, the 1/4 inch tube fittings, or the filter o-ring itself.. You have to get AIR into the system to allow the tubing to drain backward.
Like them all, but love the "B"s.
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49clipper View Drop Down
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Points: 7 		Post Options Post Options   Thanks (0) Thanks(0)   Quote 49clipper Quote  Post ReplyReply Direct Link To This Post Posted: 22 Mar 2024 at 2:00pm
Yes, air is a must, but I have checked for those multiple times with no leaks.  
For the filter to be part of the oil pressure result, it would have to be flooded all the time.  It is not flooded.  I filled the canister as much as I could, but it just drains to the crankcase with gravity flow and then would be partially drained by the next start.  My filter is filled with cotton, and I have tried two new filters with no change.   Amazingly, I went out to the shop today and started it and it showed oil pressure without any priming.   Wow, First time since I rebuilt the pump!!  I guess this is going to be a guessing game on oil pressure.   It is sort of a baffling system.  Thanks for your reply.
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steve(ill) View Drop Down
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Points: 81414 		Post Options Post Options   Thanks (0) Thanks(0)   Quote steve(ill) Quote  Post ReplyReply Direct Link To This Post Posted: 22 Mar 2024 at 6:31pm
filter does not have to be flooded... It is like a WET TEE SHIRT crammed into a box.. Try to blow thru that.... PRESSURE on the top forces the oil down thru the WET COTTON and then it drains back to the sump... BUT on top of the filter, there is a few pounds of pressure....  On a good engine you have  15 psi at the gauge ... When they get OLD, you might have 5 psi at idle and over 10 psi at full throttle.

Take a foot long piece of 1/2 inch pipe... Cut up a tee shirt into a 6 x 6 square.. Soak it in oil and POUND it into the pipe with a hammer and screw driver... Then BLOW on the end if it...Wink


Edited by steve(ill) - 22 Mar 2024 at 6:34pm
Like them all, but love the "B"s.
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Dakota Dave View Drop Down
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Points: 3940 		Post Options Post Options   Thanks (0) Thanks(0)   Quote Dakota Dave Quote  Post ReplyReply Direct Link To This Post Posted: 22 Mar 2024 at 7:54pm
My CA had low pressure when it locked up It had water changed to Ice in the pickup. When I took it apart the plug was missing from the front end of the cam. I got one and the spring from the Agco dealer when I put it back together. It had normal pressure. The only thing I did to the pump was replace the sheared drive pine in the rear end of the cam.
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john2189 View Drop Down
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Points: 304 		Post Options Post Options   Thanks (0) Thanks(0)   Quote john2189 Quote  Post ReplyReply Direct Link To This Post Posted: 23 Mar 2024 at 7:43am
Ok I’ve read this post a couple of times. What I get from it is that low or no oil pressure doesn’t effect the rods and mains since it is a splash system.
And that all the oil pump does is pump oil into the oil filter and cam bearings.
I have not seen anything about how the oil pump pumps oil to the valve rocker arms and in the newer engines to the governor

Edited by john2189 - 23 Mar 2024 at 7:47am
'41 Allis B
'45 Allis B
'49 Farmall Cub
'72 IH Cub
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steve(ill) View Drop Down
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Joined: 11 Sep 2009
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Points: 81414 		Post Options Post Options   Thanks (0) Thanks(0)   Quote steve(ill) Quote  Post ReplyReply Direct Link To This Post Posted: 23 Mar 2024 at 7:54am
No.... the pump does NOT pump oil thru passages in the crank and FORCE oil thru the main and crank bearings, like a regular car/ truck engine..

What it does is pump oil down a HOLLOW CAM SHAFT from back to front.. There are several pin holes in the cam that point at the pistons / rods that SPRAY the 15 psi oil at the  bearings and rod... the oil drips down into a hole in each rod bearing and gets into the bearing area.... Think of a SPLASH LUBE on the old Briggs & Stratton engines..

That is 85% of the oil... The other 15% of the oil comes out from the bellhousing thru the 1/4 inch pipe toward the filter... You will see a couple small tubes on the filter housing that go to the TOP END ROCKER ARMS and to the GOVERNOR Bearing.... The 15% oil in the filter is cleaned and dumped back to sump...

If you PLUG the filter, you get 100% oil THRU THE CAM and SPRAY at the internal bearings... If you have a HOLE in the filter or NO FILTER, you allow too much of the oil to run back to sump and maybe only have 50% for lube and 50% lost to sump.
Like them all, but love the "B"s.
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steve(ill) View Drop Down
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Joined: 11 Sep 2009
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Points: 81414 		Post Options Post Options   Thanks (0) Thanks(0)   Quote steve(ill) Quote  Post ReplyReply Direct Link To This Post Posted: 23 Mar 2024 at 7:59am
Reread the 5th post from DICK L several years ago... He explains that BEARING WEAR does not effect the PRESSURE since the bearings are SPRAY LUBED... You have to have PRESSURE and OIL to make the system work.

There are two BIG differences in the "B" engine compared to a TRUCK...

-- One is that 15% of the oil goes thru the filter and dumps to sump on the B.. On a truck 100% of the oil goes thru the filter and then LUBES THE BEARINGS.

--Second, the "B"  SPRAYS the oil at the bearings, similar to a SPLASH LUBE mower engine, as compared to a truck that FORCES OIL PRESSURE into the bearings thru oil galleys.


Edited by steve(ill) - 23 Mar 2024 at 8:09am
Like them all, but love the "B"s.
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john2189 View Drop Down
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Joined: 11 Sep 2009
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Points: 304 		Post Options Post Options   Thanks (0) Thanks(0)   Quote john2189 Quote  Post ReplyReply Direct Link To This Post Posted: 23 Mar 2024 at 8:10am
Ok I kinda get it now.Its been years since I’ve rebuilt a B engine but I have an old engine from a C. I guess I will have to take it apart so I visualize it better.
'41 Allis B
'45 Allis B
'49 Farmall Cub
'72 IH Cub
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steve(ill) View Drop Down
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Joined: 11 Sep 2009
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Points: 81414 		Post Options Post Options   Thanks (0) Thanks(0)   Quote steve(ill) Quote  Post ReplyReply Direct Link To This Post Posted: 23 Mar 2024 at 8:12am
Drawing in manual with circles around the SPRAY HOLES in the cam shaft.. You NEED flow thru the cam and spray out of these holes for bearing lube... Dick says the oil is THROWN OUT of the cam by centrifugal force... I like to think there is some PRESSURE in the cam and it is SPRAYED out of the holes..

Note items 10 and 11 at the front end of the cam..That plugs the hole and helps maintain SOME pressure inside the cam oil passage.

 


Edited by steve(ill) - 23 Mar 2024 at 8:15am
Like them all, but love the "B"s.
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BrianC View Drop Down
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Points: 1619 		Post Options Post Options   Thanks (0) Thanks(0)   Quote BrianC Quote  Post ReplyReply Direct Link To This Post Posted: 23 Mar 2024 at 8:59am
Re-read this post and others. One thing I need to 
know is, where is GeraldJ?
He always had good info to add.
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Les Kerf View Drop Down
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Points: 793 		Post Options Post Options   Thanks (0) Thanks(0)   Quote Les Kerf Quote  Post ReplyReply Direct Link To This Post Posted: 23 Mar 2024 at 9:11am
Originally posted by steve(ill) steve(ill) wrote:

...

If you PLUG the filter, you get 100% oil THRU THE CAM and SPRAY at the internal bearings....


Ummm... doesn't some of that oil still go to the top end even if the filter is plugged?
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steve(ill) View Drop Down
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Joined: 11 Sep 2009
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Points: 81414 		Post Options Post Options   Thanks (0) Thanks(0)   Quote steve(ill) Quote  Post ReplyReply Direct Link To This Post Posted: 23 Mar 2024 at 9:17am
YES... my point was if the FILTER is plugged, then no oil is dumped to sump... I  goes thru the cam and it goes ( at the filter housing) thru the 1/8 inch tubes to the rocker arms and governor.

Gerald left in Jan of 2021 ............ ???


Edited by steve(ill) - 23 Mar 2024 at 9:20am
Like them all, but love the "B"s.
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Les Kerf View Drop Down
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Points: 793 		Post Options Post Options   Thanks (0) Thanks(0)   Quote Les Kerf Quote  Post ReplyReply Direct Link To This Post Posted: 23 Mar 2024 at 9:47am
I re-read the manual and noticed that the oil pressure relief dumps the excess oil to the inside of the camshaft where it can still be utilized; clever.
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IBWD MIke View Drop Down
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Gerald left in Jan of 2021 ............ ???
[/QUOTE]I believe Gerald J. should be added to the Memorial section. I had forgotten about him, he did have lots of knowledge.
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Points: 3560 		Post Options Post Options   Thanks (0) Thanks(0)   Quote HudCo Quote  Post ReplyReply Direct Link To This Post Posted: 24 Mar 2024 at 11:24am
take the pickup tube off and replace it , i belive it is 3/8 npt about 8 1/2 inches long  ,ifinley replaced mine it had a tiny crack in the pipe up close to where it threads inthe block and would suck air .     i had done the pump when i put a clutch in it didnt help worked the fiilter base didnt help filled it a gallon over full and had oil presure but would loose it going ing down a hill  .    i ran mine that far over full for two years cnat believe the main didnt leak 
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