I really hope those is the right section for this post. Please forgive me if not. Okay so I took my cylinder heads to the engine shop to be machined down for head gasket replacement (‘94 4.0L ZJ). While there, they ran (I’m assuming) some kind of compression test and called me back to tell me my heads were shot. They said there were several micro fractures throughout it I understood them correctly. Obviously I’m in need of new heads but with 300k on the engine, what would you guys replace? I was planning to just replace the heads (I recently purchased new lifter rods and rockers) but my dad seems to think it would be in my best interest to buy a long block. It will be a daily driver. I would prefer the smart option over the cheap option 80/20. If we’re talking $200 vs $2000 I’d cheap it. But if we’re talking $500 to nervously run 20,000 miles vs $2000 to run another 100k miles, I’d go with the later. If I’m missing any info you’d like feel free to ask! Thanks guys!

 

What engine?

 

what a mistake lol. The 4.0L

 

It was no mistake. You said so in your post, but talked about HEADS as opposed to the one head it has. Mabbco Engines in Tyler TX has a premium long block with no core required and a limited 1 year warranty for $1300. I bought a short block for my 2000 WJ for $920 and reconditioned my "Clearwater" head. It has 6000 miles on it now and doesn't use a drop of oil and runs perfectly. The jeep has 259K miles on it and the only part of the drivetrain that's original is the front axle.

Just don't expect it to run another 300K miles because unless EVERYTHING is spot on factory specs, it won't last that long, but you should be able to get 100K more out of it with not many problems. Remember the rest of the drive train is tired as well.

 

Yeah, tha'ts what threw me.


If'n it twas me, I'd rebuild it myself, and make sure it was done right. Ask around for a trustworthy local machine shop, and do it.

 

Depending where your located and what you decide to do
https://cosprings.craigslist.org/ptd...171121955.html

 

I really like the tube header on the green one. It's set up for the CA cats.