Gutless with blue smoke

[93xj97347]

We bought my wife's xj almost a year ago with 230k on it. It's up to 246k now. It's a 93 w/4.0 Ever since we bought it it has had it's oil changes on time and all maintenance done on time. I lifted it about 6 months ago. I noticed a small decrease in power with its new 31's because of not regearing it yet due to lack of fund's. About 3 month's ago it started becoming really gutless. My 93 with 35's and stock gearing has more get up and go. Then about 2 week's it started pouring blue smoke. I'm burning about a quart for a tank of gas. I'm thinking that the ring's are bad and I'm losing compression. What are some things I should look for before I decide to build a new motor to drop in there?

[cantab27]

compression test will tell ya .......oily exhaust ???

[93xj97347]

Nope. Just a lot of blue smoke. I'm gonna get a compression tester this next week

[Mudderoy]

Nope. Just a lot of blue smoke. I'm gonna get a compression tester this next week

Let us know what you find out. Seems like you're looking for 140 lbs and all the cylinders should be close to the others. There's a percentage, I think, but can't remember.

[4.3LXJ]

Does it smoke all the time or just when you let off the gas?

[Cheromaniac]

There should be no more than a 10% variance in compression between cylinders but if they're all below 140psi, the engine's toast anyway.
If you repeat the compression tests and get significantly higher readings after adding a teaspoon of engine oil to each cylinder (allow a few mins. for the oil to soak around the rings), you'll know for sure there's ring/bore wear.
Depending on your budget and the timeframe you have to get your Jeep back to full health, your choices are:

1. Stock rebuild of your existing engine.
2. Stroker rebuild of your existing engine.
3. Swap in a lowish mileage stock junkyard engine.
4. Buy a reman. stock 4.0 engine.
5. Buy a stroker long block engine.

[93xj97347]

Smoke's all the time. Doesn't matter if it's cold or warm. Got to wait til Wednesday to get a compression tester

[slvmart]

Leak down test should be able to identify if you have a ring or valve problem. Back in the day a common problem used to be the valve guide seals.

https://www.youtube.com/watch?v=WgrfT0LFMhc#t=1082

[4.3LXJ]

Smoke's all the time. Doesn't matter if it's cold or warm. Got to wait til Wednesday to get a compression tester

If it smokes all the time, then probably bad rings. The compression tester will verify that I think