Jeep LS Swap Part 2: Donor Teardown

“You’re going to do what with this truck?”

Wait, let me back up.  When I started the not-so-harebrained-project of swapping my Jeep XJ’s lump of iron 4.0 for a Chevy Gen III small block (AKA “LS”), I did what I always do: read everything and scour the Internet for parts.  One of the first pitfalls I ran into wasn’t so much finding a suitable engine, but finding one that I could trust without spending a bunch of money basically building a new one, as well as a lot of the other supporting parts needed to make this swap a success.

The last nail in the coffin for a junkyard donor was my timeline for this project would also nullify any major component warranties, so it would be a crap shoot for me if there was a problem.  Decision made, I set my sights and online classifieds search for a suitable donor vehicle.  Timing being everything, I literally found a 2003 Chevy Suburban 1500 with 4WD within a week.  A couple of blocks from my house.

Sorry Suburban, you are NOT going to like what happens next…

Before I continue, I must make a sad announcement: this engine swap as it sits will never be legal in the state of California due to the fact that I made a major mistake on engine classifications, combined with some recent revisions to the engine change process.  Turns out that despite the fact that my engine is classified as a ULEV engine, which is more stringent than the “meh, air quality’s overrated” Tier 1 Federal emissions package on my 4.0, I can’t swap it into my Jeep because it is classified as a Medium Duty Vehicle in California.  See, the EPA has emissions classes, and the Suburban falls into LDT just like my Jeep does, but in California (of course it’s different), the Suburban is certified to Medium Duty Vehicle standards.  The reason this is no longer legal is because you cannot cross certifications, even if the certification is more stringent.  An LDT engine must go into an LDT vehicle, regardless of whether it’s cleaner or not.

Before checking any engine change donor, check its emissions label to make sure it’s compatible with your vehicle from a CARB standpoint, not EPA. As you can see, this engine bears the MDV class.

Amusingly, Chevy went back to the LDT2 standard for the LM7 Vortec 5300 in 2007 for Silverado/Sierra Classics and Express 1500 vans.  I will see what can be done to adapt my engine to these standards, or if I’m completely hosed and will need to start over.  Either way, learn from me, make sure to get an LDT engine prior to spending a bunch of time on this.

So, outside of perusing shitboxes in the junkyard for lables, how do you find out what class your donor engine is certified to?  Not easy.  First, go to ARB’s Onroad Certification Program’s listing and click on the date (why a date? Dunno) next to the model year under “PC_LTD_MDV_MDEV” to be confronted by an insane list of documents with the manufacturer’s abbreviation followed by gobbledygook for file names.  In my case, I went to the filenames starting with “GM” and then looked for filenames that ended with “5d3” which refers to the LM7’s 5.3L displacement.  If you clicked on 2003 like I did, you’ll see that literally ALL of the Gen III smallblocks have either MDV or PC in the filename, which means Medium Duty Vehicle or Passenger Car, neither of which are legal in my LDT1 Jeep.  Fack.

Page of research fail on my part. As you can see: there are no 5.3L engines in LDT, and I’ve clicked on a lot of files here in some vain hope ARB just named the document incorrectly…

In any case, this swap is happening.  I’ve gone this far, I’ll see what I can do on the other side with the ref, or I’ll just go full stupid and green sticker the vehicle.  Anyway, back to your regularly scheduled vehicular lunacy.

The Suburban itself was cosmetically not so great, but engine started right up, the AC blew cold, and there were no bad sounds coming from underhood other than a slight tick from an exhaust leak.  With 200,000 miles on the clock, there was the expected check engine light, but my code scanner pointed to the ubiquitous misfire code and considering I was going to refresh the entire ignition system, not cause for serious concern.  After disclosing there were backfees, I explained that wasn’t a concern since I was using it for parts (hence the response at the beginning of this article), a deal was struck for a measly $1500 (engine/trans/wiring harness combos sell for about this, no emission equipment included) and I drove my new find home.  Since the tags were expired, I didn’t take it for an extended drive, but I live in the lightly-enforced sticks, so there was much hoonage on the way home.  Despite hauling around a giant soccer tank, the trusty old LM7 could still put down a solid pair of black stripes (though there was some alarming ping due to pretty old gasoline) and the not as trusty (but 100% original) 4L60E transmission shifted solidly through all gears.  Score.


    1. Pretty much. From James Madison:

      The internal effects of a mutable policy are still more calamitous. It poisons the blessings of liberty itself. It will be of little avail to the people, that the laws are made by men of their own choice, if the laws be so voluminous that they cannot be read, or so incoherent that they cannot be understood: if they be repealed or revised before they are promulgated, or undergo such incessant changes, that no man who knows what the law is to-day, can guess what it will be to-morrow.

  1. Very interested in the project. Hoping to do the same thing in my 2000 Discovery some time over the next year or 2. Fortunately, I don’t have any emissions requirements.

Leave a Reply

Your email address will not be published. Required fields are marked *