Eva Brown: The Build Begins

"Rock Bottom" (rockbottom81)
08/20/2014 at 09:57 • Filed to: None

So yesterday, I started my journey towards installing a Mercedes diesel engine (an OM617, to be exact) in my Cherokee. Why an OM617? Glad you asked. In a word: simplicity. I love that these engines, with basic care, last pretty much forever. Wiring is simple, power is adequate, and they fit reasonably well where a 4.0 once lived.

I do love the 4.0... sometimes. It makes the right sounds and is plenty powerful, but it has a habit of knowing exactly when to have odd electrical problems. Like a Porsche 928, it can smell fear. Oh, you're 10 miles deep in the woods? I don't think you need a functioning throttle position sensor here! Late for work? How about I help you by ignoring the crank position sensor... again. MAP sensor? Who needs a MAP sensor??? I know, I know: all of these are totally normal and totally fixable problems (except for that pesky once-a-month misfire that NOBODY can diagnose), but I'm using them as an excuse to build the Cherokee I really want.

And for the record, I'm not planning to do anything wild like burn veggie oil or biodiesel. At least not at first...

Read this little bit about the OM617, if you have time to waste: !!!error: Indecipherable SUB-paragraph formatting!!!

So, here's the Jeep. It's a 1991, California car (now living in Michigan), drives perfect but has just enough electrical oddities to get on my nerves!

And here's the heart to be transplanted: a 1983 Mercedes OM617. It's dirty (which is understandable for a 31 year old engine), but it runs. It definitely needs some pump tuning, glow plugs, and new fuel filters, but the turbo is in good health and it has pretty good compression. I'm going to degrease it, remove the EGR, and clean up the vacuum lines. I might pull the pan off it and look at the rod bearings while it's on the stand.

And here's the W123 getting it's heart ripped out. If anyone wants to come to South East Michigan for a cheap, low-rust W123 with no engine, let me know.

So I got the engine out around 9:00pm last night with the help of my bad-ass cousin. I need to get a bunch of really long metric bolts to stick it on the stand today. Then the degreasing shall begin...

DISCUSSION (23)

505Turbeaux > Rock Bottom
08/20/2014 at 10:01

those 617's are HEAVY motors. Pulled quite a few. Any reason you went with a 617 over a 603? 603 too long or do you hate the pre combustion chamber engines?

RamblinRover Luxury-Yacht > Rock Bottom
08/20/2014 at 10:03

cheap, low-rust W123 with no engine, let me know.

Well, I'll ask him, but I don't think he'll be very keen. E's already got one, you see!

Frenchknight.jpg

Actually the family does already have a 240D with the engine out, a 240D with the engine in, and a 300D we're fixing fenders on. In addition, we've got an OM617 on the shelf that's going to be stuck in a 60s Land Rover, because that's how we roll.

RamblinRover Luxury-Yacht > 505Turbeaux
08/20/2014 at 10:09

A 603 would be too long for a Rover, I know that. The 617 is kind of too big, but can be made to fit just right.

*insert convoluted sexual reference involving Goldilocks*

505Turbeaux > RamblinRover Luxury-Yacht
08/20/2014 at 10:11

lol oh man.

I just know the 4.0 renault/AMC 6 lump is a pretty long motor, didn't know if there was space for that. 2.5T 602 from a w124 would go in there though

Cé hé sin > Rock Bottom
08/20/2014 at 10:11

Did you ever get diesel Cherokees in America? When they arrived in Europe they had a VM diesel and were quite common for a while before gradually dying a death.

yamahog > Rock Bottom
08/20/2014 at 10:14

Oh, you're 10 miles deep in the woods? I don't think you need a functioning throttle position sensor here! Late for work? How about I help you by ignoring the crank position sensor... again. MAP sensor? Who needs a MAP sensor???

HAHAHAHA, yuuuuup. The 4.0L itself will keep truckin til the second coming, (mine's at 244k) but the sensors and everything else around it? Not so much. One of the mods on a Cherokee forum has the tagline "IT'S ALWAYS THE SENSOR."

And not that it's relevant anymore, but my misfire was just a fouled cyl. 5 spark plug, it didn't throw a code until it was acting up real bad on a particularly rainy day.

Good luck with the swap and hope to see more build pics and eventually trail pics!

Rock Bottom > yamahog
08/20/2014 at 10:19

Yeah, mine never throws a code. Ever. It's the most mysterious thing! I work with a guy who was a calibrator on the HO at Chrysler back in the day and even he has no idea what is did to deserve this! Whatever it is, more compression ignition will fix it!

Rock Bottom > Cé hé sin
08/20/2014 at 10:22

We had diesel Cherokees back in the late 80s, but those used a Renault engine that was known for dying an early death. It also made less than 100 hp, so they were supposed to be pretty awful to drive. I would love to drive a VM Cherokee some day, but they never made it to this side of the pond :(

Rock Bottom > 505Turbeaux
08/20/2014 at 10:28

The OM603 is longer than the OM617 and would require a little cosmetic surgery to work. I saw a build thread where a guy had to lengthen his Jeep by like 4 inches to fit one. That's WAY more work than I want to do! I did consider an OM602 (they're SUPER cheap), but then basically tripped over this one so I snatched it! Plus, several people have already done this exact swap, so I won't be breaking any new ground. I hate being a guinea pig!

And the 617 has precombustion chambers, too. I think all Mercedes diesels do??? It's also not really much heavier than the boat-anchor that is the 4.0. The Jeep engine weighs like 525 lbs! I guess that's why they live so long, mechanically...

VincentMalamute-Kim > Rock Bottom
08/20/2014 at 10:28

"If anyone wants to come to South East Michigan for a cheap, low-rust W123 with no engine, let me know"

Crap, why do you have to say things like that? Have you no concern for others? Now I have to seriously think about the thought of towing that back across to the other side of the lake, sourcing an LS engine and plugging that in there. I love the W123 body style, hated the ridiculously low power of the turbodiesel. By cheap, I assume you mean really really cheap, right?

505Turbeaux > Rock Bottom
08/20/2014 at 10:37

oh yeah I forgot the 617 wasnt an IDI. Yeah the 602 is a good choice too but hell the 617 will run literally forever. Psyched for you to keep us up to date on this!

Rock Bottom > VincentMalamute-Kim
08/20/2014 at 11:00

I would entertain any reasonable offer! And for the record, when I drove it home, I kept thinking "Man, this thing would be really nice with an LS in it!" It rides super nice and goes down the road amazingly well. It just needs more power!

Rock Bottom > 505Turbeaux
08/20/2014 at 11:01

Thanks! I'm super excited to get this thing together and on the road!

VincentMalamute-Kim > Rock Bottom
08/20/2014 at 11:30

Sounds like "free" is out? That's not a reasonable offer? ;) I gotta talk to my buddy who would or would not prod me into stupid projects. Seriously though, I have no idea what 1980's Mercedes without an engine reasonably goes for. Maybe Oppo could chime in.

I bought a 98 Forester for $475 needing head gaskets, valve adjustment, timing belt, clutch, cat, wheel bearings, windshield, new brakes all 4 wheels, new suspension all around, both front axles. You could say I bought the Subie basically without an engine. But a Subie isn't comparable to an MB either. And a 98 car isn't comparable to an 80's MB. But then if this isn't really cheap, a stupid project on it isn't that enticing either. Please convince me either way!

Rock Bottom > VincentMalamute-Kim
08/20/2014 at 12:04

My plan was to put in Craigslist for $750 obo (stressing the "obo" part). I also have no idea what these are worth, but this being Michigan and these being mechanically indestructible, I can only assume that there is at least one guy around here with a fine running rust-bucket W123 that needs a cleaner body to swap his oily stuff into... so I guess it really just comes down to what the car's worth to that one guy (or one hoon, like yourself). Oh, and the stock auto comes with it and works well!

VincentMalamute-Kim > Rock Bottom
08/20/2014 at 12:22

$750 doesn't sound unreasonable. Lower would be better for me since it would be for a stupid project and I have really no need for and in fact really should not be getting a fifth car. I drive by a rusted out W123 on the way to work that actually would be a perfect candidate for the guy to swap his bits into. Maybe I should leave him your info if I don't go with this. So hopefully my buddy will talk me out of this project even if you aren't

NaturallyAspirated > Rock Bottom
08/20/2014 at 13:22

A little turbodiesel engine always seemed like a great fit for the XJ. Cool swap, I'll be interested to see how it progresses.

I'm a little surprised to see your comment about the HO 4.0 having sensor issues. My buddy had one of the old "Renix" 4.0 XJs and that thing never ran right, but my own '96 XJ never had any issues. Maybe I'm just lucky.

Rock Bottom > VincentMalamute-Kim
08/21/2014 at 08:10

I also happen to know where a Jaaaaag V12 is sitting... just looking for a car to go into... if you see where I'm going with this...

Rock Bottom > NaturallyAspirated
08/21/2014 at 08:20

It's most likely that I'm just unlucky. A vast majority of people seem to have very little trouble with their HO engines. Mine seems to be the exception. The Renix engines seem to be ok, as long as you sort out that one huge electrical connector on the firewall.

This whole diesel mess started because I was standing in line at the autoparts store, about to buy another throttle position sensor and another ignition coil. I thought about how much I was spending in bits and pieces like this (every single sensor has been replaced at least once, along with a bunch of other crap). I started doing future cost projections in my head (while staring at a very nice car wash sales display) and determined that this engine was costing me more than I was getting out of it. I love diesel engines and I love my Cherokee, but I hate VWs and have no use for a giant truck. I decided a diesel Cherokee had to happen.

I didn't buy the TPS and coil.

Brandon the Accuser > Rock Bottom
08/21/2014 at 12:54

I love the paint job

Rock Bottom > Brandon the Accuser
08/21/2014 at 12:58

All it took was a case of spray paint, a case of beer, and a friend dumb enough to help!

Brandon the Accuser > Rock Bottom
08/21/2014 at 13:16

And three days and you getting high on spray paint fumes.

Rock Bottom > Brandon the Accuser
08/21/2014 at 13:31

It was only two days of being stoned.