Welcome! Please use the navigational links on your left to explore our website.

Company Logo Shop Now
   Allis Chalmers Case Farmall IH Ford 8N,9N,2N Ford
   Ferguson John Deere Massey Ferguson Minn. Moline Oliver
 
Marketplace
Classified Ads
Photo Ads
Tractor Parts
Salvage

Community
Discussion Forums
Project Journals
Your Stories
Show & Pull Guide
Events Calendar
Hauling Schedule

Galleries
Tractor Photos
Implement Photos
Vintage Photos
Help Identify
Parts & Pieces
Stuck & Troubled
Vintage Ads
Community Album
Photo Ad Archives

Research & Info
Articles
Tractor Registry
Tip of the Day
Safety Cartoons
Tractor Values
Serial Numbers
Tune-Up Guide
Paint Codes
List Prices
Production Nbrs
Tune-Up Specs
Torque Values
3-Point Specs
Glossary

Miscellaneous
Tractor Games
Just For Kids
Virtual Show
Museum Guide
Memorial Page
Feedback Form

Yesterday's Tractors Facebook Page

Related Sites
Tractor Shed
Ford 8N/9N Club
Kountry Life
  
Ford Tractors Discussion Forum
:

low oil pressure in diesel

Welcome Guest, Log in or Register
Author  [Modern View]
dean schultz

07-19-2014 18:36:28




Report to Moderator

I own a 1958-1962 01 series tractor. I don"t know what model, all of the numbers above the starter have corroded away. It is a diesel. When started the oil pressure is around 40psi but after warming up it drops to 18-20psi. I am wondering if I could get away with dropping the pan and installing new bearings? I cannot afford to have it rebuilt. I"m really hoping someone here can help me fix this as cheaply as possible. The tractor starts very easily and works pretty good otherwise.

[Log in to Reply]   [No Email]
Dean Schultz

07-21-2014 12:49:05




Report to Moderator
 Re: low oil pressure in diesel in reply to dean schultz, 07-19-2014 18:36:28  
If I plastiguage the mains and they are out of spec how do I determine which size bearings to buy. I haven't worked on a tractor in 30 years and want to get it right the first time. Also, thank you all for taking the time to reply to my dilemma.



[Log in to Reply]  [No Email]
Bern

07-21-2014 14:30:58




Report to Moderator
 Re: low oil pressure in diesel in reply to Dean Schultz, 07-21-2014 12:49:05  
If the old bearings are standard size, they'll either be stamped with a "STD" on the backside, or nothing at all. If they are undersized, they'll be stamped ".010" or something similar.

If your plastigauge check shows that you are only a few thousandths out of spec, that simply means a worn bearing and you can go back to whatever size was already in there.

Be advised that standard size bearings are available in red and blue. I usually get whatever is cheaper.

[Log in to Reply]  [No Email]
Dean Schultz

07-21-2014 12:43:47




Report to Moderator
 Re: low oil pressure in diesel in reply to dean schultz, 07-19-2014 18:36:28  
If I plastiguage the mains and they are out of spec how do I determine which size bearings to buy? I haven't worked on a tractor in 30 years and want to get it right the first time.



[Log in to Reply]  [No Email]
TimInd

07-20-2014 20:42:34




Report to Moderator
 Re: low oil pressure in diesel in reply to dean schultz, 07-19-2014 18:36:28  
Sorry I did not get back to all you sooner. The way that you can really foul things up by installing new bearings in an old engine is this;
As the rod bearings wear, the piston drops a little in the bore, since the top bearing half is now thinner. At the same time, the cylinder ridge at the top of the bore gets a little wider, since the piston has dropped because of the bearing wear. Put in new bearings, and you now reset the piston travel upwards, like when it was new. Except that now, the top piston ring will hit the old, now wider ridge on the cylinder. Pow, broken ring or cracked ring land, or both. I suppose this same effect could be done on worn main bearings, since the whole assembly has dropped due to the worn bottom main bearing halves.

[Log in to Reply]  [No Email]
sotxbill

07-21-2014 05:43:42




Report to Moderator
 Re: low oil pressure in diesel in reply to TimInd, 07-20-2014 20:42:34  
If you roll in a new top bearing that is thicker and back to spec,, would it not drop the crank back down to center????

I would only worry about the ridge if you just replacing the bottom bearing.. On the last engine that I helped a bil do, we replaced all bearings except the thrust bearing as it was too tight... replace oil pump and he got another 90,000 out of the engine before he retired it. Oil pressure went back to normal. It was on a construction van used to haul equipment to and from the job.

[Log in to Reply]  [No Email]
Bern

07-20-2014 21:35:07




Report to Moderator
 Re: low oil pressure in diesel in reply to TimInd, 07-20-2014 20:42:34  
I understand what you are saying, in theory only. My question to you below was, are you speaking from experience here, or is this something someone told you in passing?

I'd argue that the opposite occurs, however. More than once I've seen rod bearings that have gone out, and the result is pistons hitting the cylinder head and/or valves. Why? On the exhaust stroke, the inertia of the piston coming up allows it to over-travel when the bearings are worn.

On the compression stroke, I could see your point, however on the exhaust stroke, I'd argue that the opposite occurs. This would negate the concerns you have about putting new bearings in an old engine.

I have never heard of your concern until you brought it up, and evidently, neither has anyone else who has responded.

[Log in to Reply]  [No Email]
TimInd

07-21-2014 10:09:58




Report to Moderator
 Re: low oil pressure in diesel in reply to Bern, 07-20-2014 21:35:07  
In response to the other post, no, the piston is lifted when a new bearing top is installed. In answer to your post, "Yes absolutely", it has not happened to me or my friends who are aware of this danger, but there have been incidents especially in the old tractor fraternity I belong to where this has happened. Remember, the person who does this either 1.) did not know what happened after the calamity, and did not investigate, or 2.) won't tell anyone of the foul up. That is why many people have not heard of this little complication. I stand by what I have said. If someone wants to take a chance (especially on an expensive, high compression diesel) without addressing this ridge issue, at least they are aware if they read this forum.

[Log in to Reply]  [No Email]
showcrop

07-21-2014 13:59:39




Report to Moderator
 Re: low oil pressure in diesel in reply to TimInd, 07-21-2014 10:09:58  
Quoting Removed, click Modern View to see

Tim, I can understand a concern along the line of thinking that the little extra thickness of a new bearing would push the piston a little higher, so that it could hit the ridge. However if that were to be possible it would be counteracted by the other half of the new bearing having a little more thickness and preventing the piston from getting quite as close to the ridge. Therefore myth busters have to declare this a busted suburban myth.

[Log in to Reply]  [No Email]
TimInd

07-21-2014 20:30:58




Report to Moderator
 Re: low oil pressure in diesel in reply to showcrop, 07-21-2014 13:59:39  
Your explanation makes no sense. By restoring the original height to the piston, you will run into the ridge, of which there is no clearance between the ridge and the top ring. The bottom half of the rod bearing cannot overcome that simple fact, unless it squashes the top bearing down, in which case the engine won't turn. The bottom bearing half is of no consequence, since the top of rod rests on top half bearing. Work it out on paper an you will understand. And, using an out of place quote from a class B TV program does not enhance your response.

[Log in to Reply]  [No Email]
Sean in PA

07-21-2014 12:19:51




Report to Moderator
 Re: low oil pressure in diesel in reply to TimInd, 07-21-2014 10:09:58  
Quoting Removed, click Modern View to see

So you are saying that you know that it has happened because other people have had unexplained engine failures who have either:

1.) Not known what caused the failure.

and/or

2.) Not admitted to doing what you claim was the cause of the failure.

And you are just proclaiming that this was the cause?



[Log in to Reply]  [No Email]
TimInd

07-21-2014 16:12:07




Report to Moderator
 Re: low oil pressure in diesel in reply to Sean in PA, 07-21-2014 12:19:51  
Well, I have only one indirect involvement. A friend of a friend bought a junk yard SBC. He put in new rod bearings (I don't know how bad the old ones were). He fired up the engine, and it started burning oil, and continued to do so until a complete rebuild several months later. My friend said they found cracked top rings and broken top ring lands, mix or match, on every cylinder, which had ridges. Normal wear that this SBC had did not do that kind of damage over the course of time. Also, based on all of the responses to this thread, if Schult wants to take a chance and go ahead with the new bearings, if there is enough slop in the piston pins, enough slop in the bore, and the original bearings were not worn thin, and the stars align, I will be the first one to say that he may get away without serious damage.

[Log in to Reply]  [No Email]
Bern

07-21-2014 11:22:39




Report to Moderator
 Re: low oil pressure in diesel in reply to TimInd, 07-21-2014 10:09:58  
OK, that's fine, however I stand by my theory as well, that is, your concern really is a non-issue for the reasons I stated earlier.

Many reputable engine manufacturers (Cummins, Detroit, Cat, etc.) have no problem with rolling in new main and rod bearings on a engine with high hours. If that's good enough for them, it's good enough for me.



[Log in to Reply]  [No Email]
TimInd

07-21-2014 16:15:05




Report to Moderator
 Re: low oil pressure in diesel in reply to Bern, 07-21-2014 11:22:39  
Please, I would like to see a direct quote from Cummins et al that the ridge on a bore can have no impact when new bearing halves are installed.



[Log in to Reply]  [No Email]
Bern

07-21-2014 19:52:05




Report to Moderator
 Re: low oil pressure in diesel in reply to TimInd, 07-21-2014 16:15:05  
You won't find a quote from any of these engine manufacturers that states exactly what you say, however neither will you find from them any kind of a caution with regards to your concern. If it truly was a potential issue, I'm sure it would have been addressed.



[Log in to Reply]  [No Email]
TimInd

07-21-2014 20:23:29




Report to Moderator
 Re: low oil pressure in diesel in reply to Bern, 07-21-2014 19:52:05  
Bern: It could have been addressed by mechanics simply not making the mistake.



[Log in to Reply]  [No Email]
Bern

07-21-2014 22:21:12




Report to Moderator
 Re: low oil pressure in diesel in reply to TimInd, 07-21-2014 20:23:29  
If it was a legitimate concern, I maintain that the engine manufacturers would issue cautions about it. Since it's a non-issue, you won't find these types of warnings from them. I can't prove this to you because it's simply not there to be found.

As I have said before, I have worked on engines that had rod bearings go out where the piston smacked the head and/or valves because of the loose bearings. This is directly opposite of what you maintain, which is why I don't buy your theory.

I'm not trying to be rude or difficult. I just don't buy into your theory.

[Log in to Reply]  [No Email]
NNP

07-20-2014 15:45:10




Report to Moderator
 Re: low oil pressure in diesel in reply to dean schultz, 07-19-2014 18:36:28  
don't know diesels,

but on gas engines with that problem,

I do the same as posted.

all new bearings same size that's in there, re-do the oil pump, 15w-40 or 20w-50 oil

and run it until time and money to do it right come along.

Does it fix everything?....no, but it will improve it a little.

And more importantly, a little peace of mind that the engine will keep all its parts inside, until I get to it the right way.

[Log in to Reply]  [No Email]
Bern

07-19-2014 19:50:02




Report to Moderator
 Re: low oil pressure in diesel in reply to dean schultz, 07-19-2014 18:36:28  
20 PSI at hot idle or above idle speed? If 20 PSI at idle, rest easy and leave it be. If above idle, start digging.



[Log in to Reply]  [No Email]
Sunbeam

07-19-2014 19:37:01




Report to Moderator
 Re: low oil pressure in diesel in reply to dean schultz, 07-19-2014 18:36:28  
Ford used very hard beatings in those diesels that tend to ware the crank. I know that's not what you wanted to hear.



[Log in to Reply]  [No Email]
soundguy

07-19-2014 19:04:58




Report to Moderator
 Re: low oil pressure in diesel in reply to dean schultz, 07-19-2014 18:36:28  
1, replace the gauge

2, what oil are you using?

3, yeah.. GENERALLY you can pick up a few psi with a set of new mains and rods rolled in. you can just pull what you got and get the same size and know they fit and bypass the plastigauge.

not ideal.. but you knew that when you asked. so no big deal.

4, 18 psi hot idle, while pretty low for a red tiger.. is still enough pressure to keep stuff from bumping together. My most ragged out 172 gasser has similar pressures at hot idle after hours of mowing. ie. about 20-23 psi and cold throttle of 40-45.. 35 hot throttle

I plan on running her much longer before doing anything.

[Log in to Reply]  [No Email]
TimInd

07-19-2014 21:59:16




Report to Moderator
 Re: low oil pressure in diesel in reply to soundguy, 07-19-2014 19:04:58  
DO NOT install new bearings if the engine has a lot of hours on it. The cylinder ridges will most likely break the top rings or the piston ring lands.



[Log in to Reply]  [No Email]
showcrop

07-20-2014 17:31:49




Report to Moderator
 Re: low oil pressure in diesel in reply to TimInd, 07-19-2014 21:59:16  
Quoting Removed, click Modern View to see

How could that happen?



[Log in to Reply]  [No Email]
David G

07-20-2014 09:36:09




Report to Moderator
 Re: low oil pressure in diesel in reply to TimInd, 07-19-2014 21:59:16  
I have never heard this either, how did you come by this?



[Log in to Reply]  [No Email]
Bern

07-20-2014 06:35:54




Report to Moderator
 Re: low oil pressure in diesel in reply to TimInd, 07-19-2014 21:59:16  
I've never heard of that concern before. Are you speaking from experience here, or just somebody else's speculation?



[Log in to Reply]  [No Email]
Dean Schultz

07-20-2014 07:41:50




Report to Moderator
 Re: low oil pressure in diesel in reply to Bern, 07-20-2014 06:35:54  
These pressures are at speed, not idle. I need to keep this tractor running as cheaply as possible so any advice is welcome. I don't understand how new bearings could damage the piston rings. Please explain.



[Log in to Reply]  [No Email]
Bern

07-20-2014 15:00:55




Report to Moderator
 Re: low oil pressure in diesel in reply to Dean Schultz, 07-20-2014 07:41:50  
If it was mine and I was on a very tight budget, I'd drop the pan and check the bearing clearances with plastigauge (support crank when checking mains). If the bearing clearances were out of spec, I'd roll in new bearings. If the clearances were within spec, I'd disassemble the pump and inspect for wear. If that looks OK, check the relief valve and spring closely.



[Log in to Reply]  [No Email]
Sunbeam

07-20-2014 14:11:02




Report to Moderator
 Re: low oil pressure in diesel in reply to Dean Schultz, 07-20-2014 07:41:50  
I had the same problem with a 801 went from 30W to 20w 50 and it helped.



[Log in to Reply]  [No Email]
[Options]  [Printer Friendly]  [Posting Help]  [Return to Forum]   [Log in to Reply]

Hop to:


TRACTOR PARTS TRACTOR MANUALS
We sell tractor parts!  We have the parts you need to repair your tractor - the right parts. Our low prices and years of research make us your best choice when you need parts. Shop Online Today. [ About Us ]

Home  |  Forums


Today's Featured Article - What Oil Should I Use? - by Francis Robinson. I keep seein this question pop up over and over again in discussion groups all over the web. As with many things there are often several right answers and a few wrong ones. Some purist I'm sure will disagree to no end with what I will tell you but most of us out here in the real world don't really care do we ? Some of them only bring their noses down out of the air long enough to look down them anyway. If you are like me you are only doing this old tractor stuff because you enjoy it. You ... [Read Article]

Latest Ad: Farmall A. A complete restoration of a 1939 Farmall A. Parade ready. Whole motor has been went through. New tires. Everything factory except the stack. Crank start only. OBO [More Ads]

Copyright © 1997-2021 Yesterday's Tractor Co.

All Rights Reserved. Reproduction of any part of this website, including design and content, without written permission is strictly prohibited. Trade Marks and Trade Names contained and used in this Website are those of others, and are used in this Website in a descriptive sense to refer to the products of others. Use of this Web site constitutes acceptance of our User Agreement and Privacy Policy

TRADEMARK DISCLAIMER: Tradenames and Trademarks referred to within Yesterday's Tractor Co. products and within the Yesterday's Tractor Co. websites are the property of their respective trademark holders. None of these trademark holders are affiliated with Yesterday's Tractor Co., our products, or our website nor are we sponsored by them. John Deere and its logos are the registered trademarks of the John Deere Corporation. Agco, Agco Allis, White, Massey Ferguson and their logos are the registered trademarks of AGCO Corporation. Case, Case-IH, Farmall, International Harvester, New Holland and their logos are registered trademarks of CNH Global N.V.

Yesterday's Tractors - Antique Tractor Headquarters

Website Accessibility Policy