Oaky.. here it goes..
I have a 1991 XJ I6-5speed manual

1) the fram on the left came off the truck.. fits great.. and yes I know fram sucks
2) second from the left.. napa.. in the book as the right for the truck (dont know about napa filter quality)
3) the third from the left.. Mobil1.. is an oversized filter that is supposed to fit.. good quality filter.. added filter area.. = better filtration (i want to do this)
4) the orange fram on the right is the only fram I can find that is supposed to work..
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#1 came out and goes back in great
#s 2-4 are supposed to work but only go on 1/4 turn
#2 is in the book as the right one
#4 is in the book as the right one
#3 is same width and thread size as 2 & 4

The consensus at this point is that I have the "old metric" style.. but the thread looks like a coarse thread on #1... and #s 2-4 look like they have a fine thread..

So my question:
Please help me find an up-sized mobil 1 with a thread like the Fram TG3985

thanks to any and all who can help

Tom

 

m1-207 and Mo289 are both metric and listed for the 4.0.
I dont know if theyre oversized filters though

 

awesome.. info confirmed... thank you very very much

 

Metric size placard under the hood on my 1990 XJ says M20x1.5

Jeep 1990 XJ oil filter thread pitch placard

 

A Ford Z9 fits great and is about twice the volume of the Jeep filter, and cheaper.

It is used on the Oz Ford 4.0L inline six

Dont know if that engine exists in USA

 

Sounds like the filter for the old Ford 5.0 V8, which is what I use