My Daughter bought a 88 Jeep Wrangler YJ for her first car with her own money a little over a year ago.

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[Linked Image from live.staticflickr.com]


The 258 inline six is burning oil, we're to the point it's burning 5-6 quarts every oil change and we're doing a spark plug change every 3K miles as well. Engine has great compression in it 125-130 psi on all six cylinders. The engine is a rebuilt and I had sitting on a stand in my garage for a few years as a spare for my Jeep, that we swapped in after her original engine tested 50-60 psi on cylinders 5 and 6. Engine was properly broke in after install, but it has always used oil. This makes me think the rings were installed wrong or the valves never seated properly. She tried to get 6K miles out of the last set of plugs (L to R cylinders 6 to 1):

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I converted it to PFI Systems TBI fuel injection shortly after she bought it, which made it a lot more reliable as far as starting and running. She wants to keep the Jeep which I understand as I have an 84 CJ7 that I love, and she has another vehicle to drive that's very reliable and she can take it with her when she graduates HS in the spring. She's 17 currently and a pretty good driver, but she's 17.

So I'm looking at options for the engine, and here is what I come up with.

1. Rebuild her 258 ci engine that's currently on my stand or order a rebuilt long block. $2500

2. Find a 4.0L core and drop a rebuilt/reman 4.0L running the current intake with TBI fuel injection. $3000

3. Find donor Jeep with a 4.0L and AX15 transmission, upgrading her to MPFI and a stronger transmission to eventually run bigger tires. I have a line on a running 99 XJ Cherokee with 150K on it but hit hard in the rear quarter for $1500 obo. I'm guessing $5-6K total if I decide to go through the engine and transmission before swapping with over runs on things.

4. Install a 4.3l V6 and AX15 transmission, this will set her up for a future LS motor swap and bigger tires. I just don't think shes ready for a 300 HP V8, that'll drop 100+/- lbs of weight total on the vehicle. So that's my reasoning for not going with a 5.3 or 4.8L motor right now.