Farm Equipment - just another dumb oil question

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just another dumb oil question

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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=14784
Printed Date: 03 Feb 2025 at 9:47am
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Topic: just another dumb oil question

Posted By: Josh(NE)
Subject: just another dumb oil question
Date Posted: 05 Jul 2010 at 9:08pm

I see in my manual that on a 190 gas or diesel the bearing clearences are same. So my question is why, other than oil additives, do they take different weight in oil? IE 10w 30 in a gasser and 15w 40 in the diesel.

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Allis Express
'65 190XT, 37 B, '72 170, '83 8030, and the IH 560 was a mistake

Replies:

Posted By: mooboy
Date Posted: 05 Jul 2010 at 9:16pm

I wonder if the bore & stroke are the same for the gasser and diesel. If diesel has longer stroke, bearing loads could be larger. Also, diesel engines tend to have more torque at lower RPM's, and compression ratio is about twice that of a gas engine.

Posted By: Coke-in-MN
Date Posted: 05 Jul 2010 at 9:38pm

Additave packages in the oil differ, a diesel runs at a different temp internaly. The 15/40 is a good all purpose oil for most engines but is not graded for gas use.

Gas engines in automotive use were using a 10/40 for a few years but it was found the lubricity of it was not good enough for severe service in smaller engines and 10/30 was made standard. Now the 5/30 synthetic is used in many.

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Faith isn't a jump in the dark. It is a walk in the light. Faith is not guessing; it is knowing something.
"Challenges are what make life interesting; overcoming them is what makes life meaningful."

Posted By: Gerald J.
Date Posted: 06 Jul 2010 at 12:09am

There is a whole lot more impact at ignition in the diesel than in the gas engine. Just listen to the rattle. Takes tougher oil to keep the inserts from hitting the crank.

Gerald J.