AMC 4.2L vs. Jeep 4.0L Dipsticks

[OverKnight]

My son and I are installing a 4.0L engine from a 1993 Jeep Wrangler Sahara into his 1986 AMC Eagle Limited.  A caveat with this installation is crankcase pan and oil pump pickup from the AMC 4.2L engine must be used, because the Jeep pan will interfere with the chassis crossmember.  Both of these parts fit onto the Jeep block without any issues, but then we became concerned about what the proper oil level should be.  The dipstick tube from the 4.2L engine was broken and all we had was the Jeep tube.  We were finally able to find a 4.2L tube, and we've made some measurements between the two to resolve any oil level questions.

The AMC 4.2L dipstick measures 9-7/16" from dipstick tube stop (where the tube is pressed into the engine block) to full mark.  The 4.0L Jeep dipstick measures 9-11/16" from dipstick tube stop to full mark.  Therefore, if using the Jeep 4.0L dipstick with the AMC 4.2L crankcase pan, the correct full oil level will be 3/16" above the top of the SAFE area on the dipstick.  Use of the AMC 4.2L dipstick and dipstick tube with the AMC 4.2L crankcase pan with the Jeep 4.0L engine should result in a correct dipstick reading.  The AMC dipstick tube fits readily into the 4.0L block, except the brace is bolted into a different mounting boss from the Jeep part.

3/16" really isn't a big deal, but it's good to know exactly what the correct oil level should be.

Other measurements: the AMC dipstick reads ¾" between ADD and FULL marks, while the Jeep reads 5/8" between ADD and top of SAFE area.

The part number of the AMC dipstick is 3242442 M, and the number on the Jeep dipstick is 33007167.  These numbers are from the dipsticks; I don't know the part numbers of the dipstick tubes.

I hope this is helpful to anyone installing the 4.0L engine into an AMC Eagle.

[89 MJ]

That's good information, thanks for reporting that back. I just know that Eagle's take 5 quarts of oil, but that wouldn't help much between oil changes.