C Allis No oil Pressure
Printed From: Unofficial Allis
Category: Allis Chalmers
Forum Name: Farm Equipment
Forum Description: everything about Allis-Chalmers farm equipment
URL: https://www.allischalmers.com/forum/forum_posts.asp?TID=211733
Printed Date: 18 Sep 2026 at 6:58am
Software Version: Web Wiz Forums 11.10 - http://www.webwizforums.com
Topic: C Allis No oil Pressure
Posted By: rma1998
Subject: C Allis No oil Pressure
Date Posted: 19 Jul 2026 at 11:41am
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We are working on a 40's C Allis. The tractor was rebuilt in 1988. We were told it was parked around 1998 due to low oil pressure. The previous owner is not with us anymore to ask exactly why it was parked. We cleaned up this little C, we went through the carb & magneto, Changed the oil with Rotella 15w40 . We noticed the tube in the filter was plugged, so we cleaned the tube and Installed a Fram C159. We also replaced the old oil pressure Gauge (0-30 psi). Before Starting the tractor, we removed the oil filter, and hand cranked the tractor over. Oil shot out of the filter tube. Yes oil got all over. We started the tractor, but had 0 oil pressure on the gauge. I let it run for about a minute, no change, so we shut it down. Any suggestions on what we should try. Thanks |
Replies:
Posted By: PaulB
Date Posted: 19 Jul 2026 at 12:16pm
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the tube is pushed too far onto the filter base. Remove the gauge and you will see this. ------------- 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 |
Posted By: rma1998
Date Posted: 19 Jul 2026 at 12:28pm
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We'll give that a try. |
Posted By: steve(ill)
Date Posted: 19 Jul 2026 at 12:36pm
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this is a BYPASS filter system... 85% of the oil out of the pump goes down the cam shaft and lubes the engine internals... 15% of the oil goes outside the engine thru the small 1/4 inch pipe to the filter and gauge.. That 15% is cleaned and then dumped to sump.. Not used as lube oil.. as Paul said, you might have the gauge blocked by the tube.. OR the tube may be the problem... Tube is suppose to have a VERY SMALL HOLE in the top of it.. m aybe 1/8 inch... That RESTRICTS the oil to 15% LOSS... If your 1/4 inch tube is wide open or hole too big, you will loose MOST of your oil thru the filter and back to sump...... In theory you can block the tube COMPLETELY and all the oil goes from the pump thru the cam shaft... but dont block the gauge hole with the tube.
A GOOD engine will put out 15 psi at hi idle....Should be more than 10 at an idle if it was REBUILT... If its old and tired it could be 5 psi..
------------- Like them all, but love the "B"s. |
Posted By: tbran
Date Posted: 19 Jul 2026 at 2:00pm
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We have diagnosed low oil pressure for years and as stated it is usually bleed off though the filter - on those that this is not the issue - we use a made fitting to screw into the oil passage and pressurize the system at a low regulated pressue and listen for the air leaks which would = oil leaks - several times were have found the pin that drives the oil pump in the end of the cam has worn and leaves two slots that leak around the pin . We also use a ball in the end of the cam such as in the 149-160 with a weaker spring. These 125 engines have holes drilled in the cam that spray oil in a pattern that lines up with holes in the rod big end that lubes the rod brgs. ------------- When told "it's not the money,it's the principle", remember, it's always the money.. |
Posted By: dfwallis
Date Posted: 19 Jul 2026 at 2:03pm
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My 52 CA still has pretty good pressure of 15PSI. I cleaned the pump during engine rebuild but it's never actually been rebuilt. It was for a while occasionally starting with no pressure, in which case I primed it and it was fine for a while. Recently, I have not had any need to prime it. A suction pipe leak might be possible. Might have "gummed up" enough to maintain prime after running awhile. ------------- 1952 CA13092, CA Pickup Plow, CA Cultivator, CA Two Row Planter, Dunham-Lehr GC78 Disc, Grader Blade, 3pt Fm180 Finish Mower |
Posted By: HudCo
Date Posted: 19 Jul 2026 at 3:24pm
| over fill the engine an extra gallon and see if it has oil pressure to see if there is a crack on the pick up sump tube where it screws to the block and is just sucking air |
Posted By: steve(ill)
Date Posted: 19 Jul 2026 at 3:39pm
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Before Starting the tractor, we removed the oil filter, and hand cranked the tractor over. Oil shot out of the filter tube. Yes oil got all over. We started the tractor, but had 0 oil pressure on the gauge. It would appear his pump is working and pumping oil to the filter... The oil is either a complete loss thru the filter, or the gauge is plugged up and he really has oil pressure ?? ------------- Like them all, but love the "B"s. |
Posted By: rma1998
Date Posted: 19 Jul 2026 at 5:12pm
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We checked the tube, it looks fine. We took the new oil pressure gauge off, I put an oil pressure tester in its place and it showed 12 psi at idle. Reinstalled the Oil pressure Gauge, reads zero. Bad Gauge. Thank you all for you help. I've been researching this issue for a couple weeks now. |
Posted By: Les Kerf
Date Posted: 19 Jul 2026 at 5:27pm
Thanks for the update  It's always nice to hear what the results are.
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rma1998 wrote:Posted By: John426
Date Posted: 21 Jul 2026 at 12:36pm
What is the correct length onto the filter base? How to ajust it? is it with shims? |
Posted By: steve(ill)
Date Posted: 22 Jul 2026 at 6:19pm
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its just a tube that pushes into a drilled hole... there is a CROSS DRILLED hole at the bottom to send oil to the gague.. If you BOTTOM OUT the TUBE when you install it, you could cut off the feed to the gauge.. Pull it up 1/8 inch and that is plenty of room for the oil signal to the gauge..... or cut a notch in the bottom of the tube so it can not cut off the oil passage. ------------- Like them all, but love the "B"s. |