SDman - 3/20/2025 22:13

If its got the older engine oil filter, more than likely what has happened is that the #2 piston ring land has broken on the piston, usually resulting in the #2 ring getting broken.

The first 8.3L engines had a nickle insert around the #1 piston ring land for strength, but didn't have it on the #2 ring land. More than likely a cost-cutting thing.

When CaseIH started putting these engines in the 1660s/80s at the time, this problem showed up right away in them...and CaseIH installed new sleeves/pistons on the combine engines....but rolled the dice on the tractor engines...and usually won.

7130s and 7140s got the better pistons with nickle insert(called Ni-Resist) on the second piston ring land right away; the lower HP tractors got the updated pistons at a later engine serial #. Here again, I'm sure they had a bunch of the older-style pistons at the factory, and the bean counters told the plant they had to get used up, so....

As far as low engine oil pressure....does this show up under 1800 engine RPM? Older Magnums like this had 2 oil pressure sensors....1 for over 1800 RPM, 1 for under 1800 RPM.