So, I'm looking to replace my xj's '00 4.0
This is my DD so I don't have tons of time to spend rebuilding the engine, and I'm not familiar enough to spend so much time and money only to screw something up and cost myself more in the long run. I'm too broke to have someone else do it, so a reman is my only option at this point.

I have found lots of different options, but two remanufactured 4.0 companies I've heard things about are Titan and ATK.
The Titan will run me about $2100, but comes with an upgraded cam shaft which will (so they say) give a little more HP and a little better mileage.
ATK is just bare stock, but just under $2400. I've heard better things about ATK however. Should I just go with ATK? Is there much difference at all?

Alternatively, I could buy a short block for $900
https://www.parts.com/index.cfm?fuse...ep-SHORT-BLOCK

Or another short block from MABBCO for ~$1100
https://www.mabbcomotors.com/catalog...Warranty_/1213

But the problem is that I don't know anything about those two short blocks, and they don't really have a warranty.

Should I go the short block route and save some cash, or should I go long block?

 

What's gone wrong with the current engine?

 

It was misfiring really bad on the 5 and 6, then running rough in general, got significantly worse... I've pretty much narrowed it down to a bad cam shaft or crank.

 

usually a bad camshaft is worn out lobes or broken, I don't believe it is your cam, possibly the timing chain set makes more sense. How is the harmonic balancer? in good shape? You stated you "narrowed it down" does that mean you checked the 5&6 fuel injectors for function and verified the wiring appears okay? compression check okay? are you finding metal in the engine oil? don't give up on your 4.0 that quick

 

No metal when I opened the oil pan, but compression on 6 was 90, went up to 130 after adding oil. After a few days of light driving, it went down to 40 as it progressively got worse.

Checked injectors, took them out, cleaned them too.
Wiring harness continuity test was positive, as was coil packs.

took it to my mechanic who I trust, and he said it's the engine without a doubt. He didn't go too deep looking for reasons why, neither did I. When he opened up the valve cover the exhaust push rod on 6 was snapped too...

I'm just inquiring about engines at this point, not looking to find the problem with my current one, since multiple people and multiple tests of my own have pointed me in the direction that my motor is toast.

This comes after the entire upper end was sludged up from a coolant leak from a cracked head.

 

ATK over titan.

 

What are the reasons why? I've heard a lot of people say that.

 

Because ATK is quality and Titan is not.

 

Because they don't have any control over what the end user does with it.
It sounds like ultimately you are in need of a cylinder head as well so just a short block is pointless. For a "new" engine installed you'll be in to it for ~ $3000, is the vehicle in the top 20% as far as overall condition and worth it?

 

I replaced the cylinder head a month ago, and it's a new casting from Clearwater heads... Pretty sure this problem is from coolant mixing the oil and causing a lack of lubrication internally.
I plan on doing the swap myself and can get an ATK for just over 2k. Wondering if it's better to save some money and buy the short block for 1100.

 

Buy an engine & sell your cylinder head if it's in good condition.

 

Yup. I wasn't trying to second-guess your decision, just trying to determine if you could move parts over to a short block or needed the whole engine.

ITA with ATK, drop it in and sell the new head. There's a pretty steady market for good heads.

 

right on.
What do you mean by ITA? If I sell the head, I don't get the core, so I might as well send the motor back for the core (350 bones).
I'm also conflicted because the head is beefier than a reman one that'll come with the ATK motor.... I'm afraid I'll have to replace the head again down the line, and I'm really scared of having the same issue in another 160,000 miles.

 

You may want to check but if you swap the head it will probably void any type of warranty. Those replacement engines have seals and markings so they can tell if it's been molested.

 

I'm assuming so :/