This site is not affiliated with AGCO Inc., Duluth GA., Allis-Chalmers Co., Milwaukee, WI., or any surviving or related corporate entity. All trademarks remain the property of their respective owners. All information presented herein should be considered the result of an un-moderated public forum with no responsibility for its accuracy or usability assumed by the users and sponsors of this site or any corporate entity.
The Forum Parts and Services Unofficial Allis Store Tractor Shows Serial Numbers History
Forum Home Forum Home > Allis Chalmers > Farm Equipment
  New Posts New Posts
  FAQ FAQ  Forum Search   Events   Register Register  Login Login


B Oil pressure needle bouncing, dirty inside gauge

 Post Reply Post Reply
Author
Message
resurrection20 View Drop Down
Bronze Level
Bronze Level
Avatar

Joined: 14 Nov 2023
Location: Oregon
Points: 78
Post Options Post Options   Thanks (0) Thanks(0)   Quote resurrection20 Quote  Post ReplyReply Direct Link To This Post Topic: B Oil pressure needle bouncing, dirty inside gauge
    Posted: 20 Mar 2024 at 2:10pm
Hi all, me again,

See pix for details. Oil level is full (choke still on, lol).

I was working my B pretty hard today and I looked down and noticed the oil pressure gauge was bouncing quite a bit. The white backing inside is peeling and turning brown and there seems to be a film on the inside of the glass.

After reading quite a few forum posts... seems like it's just a bad gauge.


My girl's really being needy lately!



Edited by resurrection20 - 20 Mar 2024 at 2:12pm
Back to Top
Sponsored Links


Back to Top
Codger View Drop Down
Orange Level
Orange Level
Avatar

Joined: 23 Dec 2020
Location: Illinois
Points: 2053
Post Options Post Options   Thanks (0) Thanks(0)   Quote Codger Quote  Post ReplyReply Direct Link To This Post Posted: 20 Mar 2024 at 2:30pm
Old girls need love too as they say. Most likely a bad gauge with a compromised solder connection internally. That happens and reproduction gauges in both direct reading, or electrical are available to emulate the original(s). 
A career built on repairing and improving engineering design deficiencies, shortcomings, and failures over 50 years now.
Back to Top
resurrection20 View Drop Down
Bronze Level
Bronze Level
Avatar

Joined: 14 Nov 2023
Location: Oregon
Points: 78
Post Options Post Options   Thanks (0) Thanks(0)   Quote resurrection20 Quote  Post ReplyReply Direct Link To This Post Posted: 20 Mar 2024 at 4:25pm
After I fired it back up, the needle was behaving. Of course, I don't trust it now. Better order a new one.

Edited by resurrection20 - 20 Mar 2024 at 4:26pm
Back to Top
PaulB View Drop Down
Orange Level
Orange Level


Joined: 12 Sep 2009
Location: Rocky Ridge Md
Points: 4727
Post Options Post Options   Thanks (0) Thanks(0)   Quote PaulB Quote  Post ReplyReply Direct Link To This Post Posted: 20 Mar 2024 at 7:21pm
That is inherent in the small block oiling systems as they have a 2 vane oil pump which gives a pulsing oil flow. The good quality oil pressure gauges have a very small orifice into the gauge to level this out. Probably your gauge going bad. Don't get worked up over it. I be more concerned about your filter not having the proper restriction to maintain the needed oil pressure to the camshaft and crankshaft. 
If it was fun to pull in LOW gear, I could have a John Deere.
Real pullers don't have speed limits.
If you can't make it GO... make it SHINY
Back to Top
Jim2 View Drop Down
Bronze Level
Bronze Level
Avatar

Joined: 20 Feb 2024
Location: Wisconsin
Points: 26
Post Options Post Options   Thanks (0) Thanks(0)   Quote Jim2 Quote  Post ReplyReply Direct Link To This Post Posted: 22 Mar 2024 at 9:06am
That's a nice looking piece of equipment for $500 just judging from the sheet-metal.  You did alright!  

Have only run my tractor a few times around the yard but from what I can tell mine stays pegged at maximum while running.  Then goes back to that line below "NORMAL" when the engine is off.  Was thinking I'd just run it that way.  Doesn't have numbers anyway and gives a pretty good indication that it has pressure, which is all a new gauge would show anyway.  
Back to Top
resurrection20 View Drop Down
Bronze Level
Bronze Level
Avatar

Joined: 14 Nov 2023
Location: Oregon
Points: 78
Post Options Post Options   Thanks (0) Thanks(0)   Quote resurrection20 Quote  Post ReplyReply Direct Link To This Post Posted: 03 Apr 2024 at 2:31pm
Thanks! It came with a spray rig on the back and 20 gallons of Roundup. If I used Roundup, it would have been a great savings.

What I've learned from this forum (experts abound here) is that excessively high pressure can mean your oil filter is plugged up and all the oil is bypassing it.

Or that little tube in the middle that shoots the oil into the filter could be clogged or the opening might not be wide enough Someone told me they could get pushed closed. The tube comes up and out to check all the orifices.

Neither are the end of the world, but your oil isn't getting cleaned like it should.

Or maybe you just have a messed up gauge.

Edited by resurrection20 - 03 Apr 2024 at 2:39pm
Back to Top
Jim2 View Drop Down
Bronze Level
Bronze Level
Avatar

Joined: 20 Feb 2024
Location: Wisconsin
Points: 26
Post Options Post Options   Thanks (0) Thanks(0)   Quote Jim2 Quote  Post ReplyReply Direct Link To This Post Posted: 03 Apr 2024 at 5:28pm
Will have to have a look at that.  Tractor is sitting there with the timing cover and oil pain off right now in an effort to fix leaking front crankshaft seal.  

Found out when I pulled the oil pan that the screen had fallen out of the strainer and was lying loose in the bottom of the pan.  Looked at the filter, but haven't changed it yet.  Looks like new from the bottom.  Didn't think to check to see if tube is plugged or to examine the orifice.  That's a great tip!

We're getting hit with snow here this week.  Planning to paint a few things before I button it up again, but will have to wait for better weather.

Jim


Back to Top
steve(ill) View Drop Down
Orange Level Access
Orange Level Access
Avatar

Joined: 11 Sep 2009
Location: illinois
Points: 81102
Post Options Post Options   Thanks (0) Thanks(0)   Quote steve(ill) Quote  Post ReplyReply Direct Link To This Post Posted: 03 Apr 2024 at 10:47pm
there is a spring loaded ball  (relief valve) in the pump that tries to maintain 15 psi going to the filter ( and dumps the rest down the hollow cam shaft)...

If you remove the filter or the 1/4 inch tube, you will run too much oil back to the sump and will not be able to maintain the 15 psi setting ( hi idle).... If you PLUG the filter or the 1/4 inch tube then you have NO filtered oil dumping to sump and ALL of the oil is going thru the hollow cam shaft... and it SHOULD be maintained about 15 psi.

Now if your motor / pump is worn out and you can only get 10 psi at high idle or have only 2-3 psi at low idle ... then plugging the 1/4 inch line or the filter SHOULD make all the oil go thru the cam and RAISE you pressure.. ( you might get 5-10 psi at idle ??)... but remember, the relief valve is trying to maintain 15 psi. at High idle.
Like them all, but love the "B"s.
Back to Top
steve(ill) View Drop Down
Orange Level Access
Orange Level Access
Avatar

Joined: 11 Sep 2009
Location: illinois
Points: 81102
Post Options Post Options   Thanks (1) Thanks(1)   Quote steve(ill) Quote  Post ReplyReply Direct Link To This Post Posted: 03 Apr 2024 at 11:00pm
Here is a picture of the pump on the back of the hollow cam shaft. you can see the discharge of the pump has the "RELIEF VALVE" that helps maintain 15 psi.

Also in the second picture you will see there is a restrictor "PLUNGER" at the FRONT of the cam shaft that plugs most of the hollow cam and allows SOME of the oil to spray thru it onto the front timing gears.. If you take out that plunger, you will also LOOSE pressure in the system.





Like them all, but love the "B"s.
Back to Top
Jim2 View Drop Down
Bronze Level
Bronze Level
Avatar

Joined: 20 Feb 2024
Location: Wisconsin
Points: 26
Post Options Post Options   Thanks (0) Thanks(0)   Quote Jim2 Quote  Post ReplyReply Direct Link To This Post Posted: 04 Apr 2024 at 8:35am
Hate to ask too many questions on resurrection20's thread, but kind of wondering if anyone has thoughts as to what effect my strainer failure might have on oil pressure?  I can't remember where, but saw someone else's strainer and it was pretty well plugged up.  I'm sure that would impede flow and reduce pressure.

Like I said, haven't looked at my filter tube, but seems like it may well be plugged just judging from the way the filter looked and the high reading at the pressure gauge.

I'm thinking that I may want to drill a hole in the pickup tube to wire that strainer in place. . . .  Anyone else make similar modifications?
Back to Top
steve(ill) View Drop Down
Orange Level Access
Orange Level Access
Avatar

Joined: 11 Sep 2009
Location: illinois
Points: 81102
Post Options Post Options   Thanks (0) Thanks(0)   Quote steve(ill) Quote  Post ReplyReply Direct Link To This Post Posted: 04 Apr 2024 at 9:33am
If you have access to a gauge with numbers... i would try that... The "most common" mode of "high pressure reading" is the gauge.
Like them all, but love the "B"s.
Back to Top
Jim2 View Drop Down
Bronze Level
Bronze Level
Avatar

Joined: 20 Feb 2024
Location: Wisconsin
Points: 26
Post Options Post Options   Thanks (0) Thanks(0)   Quote Jim2 Quote  Post ReplyReply Direct Link To This Post Posted: 04 Apr 2024 at 10:42am
Don't know that I've got a gauge w/ numbers.  If I did, would be doubtful that it would be sensitive enough for these low pressures.

Just came back in from another look at filter, base, oil tube, etc.  Pulled the 1/4" oil tube out, and it was as clean as a whistle--no dirt or debris of any kind and holes looked good as well.  

Only question that comes to mind is that the oil filter mounting base is full of oil.  Shouldn't that just drain down into the sump?  I'm wondering if there could be an obstruction *after* the filter that would be artificially raising my oil pressure?  Could just pull it off and try to figure it out, I guess.  

Have plenty of time, so more inclined to watch some YouTube videos or ask you all rather than get into more trouble by digging into something that really isn't an issue at all.  Likely overthinking this, but don't have a wealth of experience to draw on, so. . . .


Back to Top
steve(ill) View Drop Down
Orange Level Access
Orange Level Access
Avatar

Joined: 11 Sep 2009
Location: illinois
Points: 81102
Post Options Post Options   Thanks (0) Thanks(0)   Quote steve(ill) Quote  Post ReplyReply Direct Link To This Post Posted: 04 Apr 2024 at 1:09pm
The oil filter housing has a lip before it drains back into the crankcase... If you remove the filter, there will be a PUDDLE of oil about 1/4 inch deep or more in the housing base.

If you REALLY have more than 15 psi of pressure, its Possible that someone changed the spring inside the oil pump last time they rebuilt it, with a "will fit"..

--------------

In the PICTURE above you see item #12 and 13 are the "RELIEF VALVE".... lets not call it that.. Its more of a PRESSURE SETTING VALVE.. No matter what the valve is adjusted to, the pump puts out a given quantity of oil..  The 1/4 inch tube and orifice and filter are sized so that 15% of the oil goes thru the filter.. The other 85% of the oil goes thru the camshaft... If you TIGHTEN the spring on the "pressure setting valve", then you could get ( lets say 5 or 10) pounds more pressure inside the pump.... but the flow still remains about the same as the FILTER and the HOLLOW CAM always get a portion of the flow.


Edited by steve(ill) - 04 Apr 2024 at 1:16pm
Like them all, but love the "B"s.
Back to Top
Jim2 View Drop Down
Bronze Level
Bronze Level
Avatar

Joined: 20 Feb 2024
Location: Wisconsin
Points: 26
Post Options Post Options   Thanks (0) Thanks(0)   Quote Jim2 Quote  Post ReplyReply Direct Link To This Post Posted: 04 Apr 2024 at 2:04pm
Thanks, Steve--that matches what's going on here.  Seems like there's nothing to worry about.Big smile
Back to Top
resurrection20 View Drop Down
Bronze Level
Bronze Level
Avatar

Joined: 14 Nov 2023
Location: Oregon
Points: 78
Post Options Post Options   Thanks (0) Thanks(0)   Quote resurrection20 Quote  Post ReplyReply Direct Link To This Post Posted: 04 Apr 2024 at 2:56pm
Originally posted by Jim2 Jim2 wrote:

Thanks, Steve--that matches what's going on here.  Seems like there's nothing to worry about.Big smile


Steve(ill) is the best. He's been answering my annoying questions since November!
Back to Top
 Post Reply Post Reply
  Share Topic   

Forum Jump Forum Permissions View Drop Down

Forum Software by Web Wiz Forums® version 11.10
Copyright ©2001-2017 Web Wiz Ltd.

This page was generated in 0.061 seconds.


Help Support the
Unofficial Allis Forum