Farm Equipment - no oil pressure when hot

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no oil pressure when hot

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=28320
Printed Date: 01 Mar 2025 at 4:19am
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Topic: no oil pressure when hot

Posted By: somebody
Subject: no oil pressure when hot
Date Posted: 01 Apr 2011 at 6:32am

Hey guys I got a problem maybe some of you might offer a little advice. I have worked as equip. mechanic for 30 years but that don't mean I'm the sharpest tack in the box.

Well here goes recently rebuilt a allis chalmers 226 gas engine, had to replace a main bearing cap, so had block line bored, crankshaft turned, new cam bearings, cam is good. main and rod bearings, rings sleeves the works engine runs good, when it first starts up oil pressure is 30-35 lbs. by the time it gets to 180 degrees oil pressure is 0, Gauge is good tried two different ones, can't find an oil pump other than a used one does anyone have any ideas.

Thanks and hope everyone has a great weekend.

GOD BLESS

Replies:

Posted By: MACK
Date Posted: 01 Apr 2011 at 6:43am

Get a 10 lb gauge and instal when hot to see what it has then. MACK

Posted By: Chris/CT
Date Posted: 01 Apr 2011 at 6:48am

Which oil filter/pressure system does your engine have? Early/Late?

Posted By: Osage_Orange
Date Posted: 01 Apr 2011 at 8:28am

Be sure the metal tube that goes inside the oil filter is there.

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Why is there never time to do it right the first time, but always time to go back and fix it?

Posted By: DMiller
Date Posted: 01 Apr 2011 at 8:34am

Could be relief valve for oil pump is too weak, spring may have broken or collapsed, may need to recheck main bearing/rod bearing clearances with plasti-gauge as .001-.002 extra can rob oil from the bearings. Should try to keep oil clearance to lower end of the spec.

Posted By: Gerald J.
Date Posted: 01 Apr 2011 at 11:04am

What filter? Is the oil pressure regulator working? Its usually a pressure relief valve, might be sticking when cold, 35 psi is high for many Allis engines, then sticking open when hot. A pleated paper filter in the bypass system leads to zero pressure because the Allis pressure regulation depends on considerable flow restriction in the filter that the pleated paper filter doesn't supply.

Gerald J.

Posted By: CTuckerNWIL
Date Posted: 01 Apr 2011 at 11:23am

A broken or weak spring in the pressure relief would not allow good pressure when cold. If the filter tube was missing, i don't think you would have any pressure when cold. How are you measuring 35 PSI when cold? Do you have a 60 lb gauge on it? A 60 lb gauge won't register well in an Allis bypass system at running temp, it should have a 30 psi gauge.
I guess all this depends on if you are working on a bypass system or a late D17 with full flow system.

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Lena 1935 WC12xxx, Willie 1951 CA6xx Dad bought new, 1954WD45 PS, 1960 D17 NF

Posted By: mlpankey
Date Posted: 01 Apr 2011 at 12:11pm

if your luck is like mine it will need bearings.

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people if they don't already know it you can't tell them. quote yogi berra

Posted By: somebody
Date Posted: 01 Apr 2011 at 2:29pm

This is a D17 series 1 tractor I assume it is the bypass system. The pressure when cold was 25 and I removed the valve on side of engine and added shims to get 35 lbs, and yes I am useing a 60 lb. gauge and 10w30 oil. I think before I go any further I will change gauge to a 40 lb.max. and change oil to 40 weight just to see what happens.

Thanks for all info. guys

Posted By: BobHnwO
Date Posted: 01 Apr 2011 at 3:08pm

Shimming the spring won't help when it's hot.

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Why do today what you can put off til tomorrow.

Posted By: CTuckerNWIL
Date Posted: 01 Apr 2011 at 4:01pm

Bob, why not? It takes so much pressure to overcome the spring pressure to by pass. The spring doesn't care if the oil is hot or cold, it should take the same amount to by pass. There could possibly be a slight difference if the spring heats but I doubt you could tell it on a 60 lbs gauge.

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http://www.ae-ta.com" rel="nofollow - http://www.ae-ta.com
Lena 1935 WC12xxx, Willie 1951 CA6xx Dad bought new, 1954WD45 PS, 1960 D17 NF

Posted By: BobHnwO
Date Posted: 01 Apr 2011 at 5:59pm

I meant at idle speed, btdt.

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Why do today what you can put off til tomorrow.

Posted By: DrAllis
Date Posted: 01 Apr 2011 at 7:57pm

If it's the old "bypass" system, the lines to the oil filter base take a 7/16" wrench. There must be a tube from the center of the filter base to go up inside of the filter. Oil pressure on those systems was only 10-12 psi with hot oil. If cam brgs are new and mains and rods are new and fitted correctly ( -.010" brgs for -.010" journals) and the rocker arms have the oil tube connected, the only reason for less than spec oil pressure would be a worn out oil pump or a blown gasket on the pump gear plate on the bottom. If the pump has the newer pressure regulator built in (replaced one time with the newer style pump) and it was stuck open, that could also give you low oil pressure.

Posted By: David (in Mi.)
Date Posted: 01 Apr 2011 at 8:03pm

make sure you have tube to rocker arm assembly and plugs in the end of rocker arm tube. Oil filter and tube into are important also.

Posted By: j.w.freck
Date Posted: 01 Apr 2011 at 9:55pm

i am in agreement with dr.allis.take the oil pump out and check your geroter to end clearance on the end plate.dont have my o/h manual in here,but i believe that clearance is around .0015 on the gear to plate contact.when you remove the cover plate,ck for circular wear marks in the cover.most of them can be lapped out to obtain your gear clearance.ck the clearance with plastigage or soft lead wire...