The sound from a turbo diesel isnt as loud as you think. The turbo acts like a muffler and you will only hear a little turbo whine on spool up. Now on a naturally aspirated diesel like mine which is straight piped it sounds like a big block motor in high rpms. I happen to love it but some hate it
2015 Ford F350 crew cab, gasser
2001 Cherokee sport "AGENT ORANGE"
1991 Ford 7.3L IDI- FOR SALE
Haha I just mentioned this..I'm on peachparts, dieselbombers ect ect. I started this search about 3 months back, just found this thread by accident.
Saw some of mis-information though, so I'd figured I toss out what I know and learned over the last few months of constant research!
The Om617 aka the million mile motor is a great swap! Its virtually the same demisions as the 4.0. Slight shorter. Its a front sump & the oil ump/pick up are 1 piece, so you can only mod the pan so much, you can notch it slightly, but yes a 3" would be needed to have any kind of flex! This is the only bit worrying me about the swap..if it'll flex decently with my 3-4" lift.
The OM617 will never see 30mpgs. Sorry guys Highest reported in a hyper mileaging MB was 31mpgs, he blocked his grill, lowered his car ect ect ect..us lifted Xj will probably get 25-27mpg MAX! But alternative fuel & such will save, and diesel is pretty cheap in some states. It would be worth it in my mind! Also think if an appocolyse happened? You can run on oil, veg, ATF, ect. AWSOME!
Anyway the OM617 weighs very very similar to a 4.0..I can get exact specs, I've written them down, the OM617 was something like 60-70lbs lighter fully dressed and has similar output to a jeep 4.0, even though the stated numbers are lower. The stock IP on the OM617 has 5mm elements and the will be maxed out around 210ftlbs. They likes to be ran around 2300-2400rpm with a stock turbo. You can run a W122 N/A serious intake manifold, its got long runners and helps with low end slightly and get a cheap VNT turbo. Otherwise they don't make much for torque below 2k. The VNT setup, will spool sooner, make more power way lower/sooner, and still keep stock or better power up top.
You can run these around 2000-2100rpm but you gonna feel a little slow on the highway if its stock turbo, especially on 33's with extra weight. Similar to the feeling of big tires & stock gears. I have a 5speed and 31's & 3.55's. If I do this swap I'll be downing to 30's. Better for MPG's anyway. Currently looking for 3.73 or 4.10 axles as well, they would be a good upgrade even if I stay with the 4.0.
Cheap upgrades, gauges first! EGT, Boost, and EMP (exhuats mani pressure), run a intercooler, crank IP, stock turbo will run 12psi without issue. 3" downpipe, straight through exhaust. W112 N/a long runner intake.
After that you'll be maxed on fuel, no more to add, no more power. Options are a $1500 Myna pump upgrade, upgrade stock IP with bigger elements, or meth injection.
I actually picked up a W112 N/A manifold at a yard because I saw it and saw people selling them for 120+, so I already have that incase I do the swap if not I'll sell it.
Honestly for me its searching the clearence and the wiring for the swap. If its easy enough then I will be undertaking it!
If not then my 4.0 gets a 4.2L mini stroker/efficient rebuild that I've mentioned a few times...
.038 quench, 9.6:1 on 91 oct...250/310ftlbs..with the higher comp and tighter quench it should get better than a stock 4.0 and it'll have better emmisions to boot! I'd guess my mileage would increase from 22 to maybe 25mpgs. But with gas going up, I want a diesel for bio fuels.
I just think of it this way, find a good donor OM617, with a solid bottom end. Cause a full rebuild is around 3000 in parts. Junkyard charges 150 or so complete motor. Rebuild & port/clean up head, polish intake & exhaust runners glass smooth, no roughness on intake since its diesel, that'll help spool and flow & power & efficiency. Shave head .01 to raise comp to 22.5:1 from 22.2:1, its apart so why not lol, get a little more out of it, 3 angel back cut on the valves since its cheap & its apart, to pick up a little more flow and then rebuild head to stock specs. New timing chain and that'd be it! Cost maybe 750? I can port & rebuild it myself, its one of my favorite hobbies.
Then sell my 4.0 - $350 (and thats being cheap, usually 400-550 here)
Sell Ironman motor mounts - $70
Sell Safc II - $200
Sell LS1 valves, springs, retainers - $120
Sell 61mm renix bored throttle body & TB spacer (biggest bored renix TB to date haven't found an equal size or bigger yet) -$75
That alone would put around 800 back in my pocket..so essentially I could do this for almost free!
The OM617 is not smooth, saw that posted lol. They are mildly loud, clatter when your running it hard, so don't expect a quiet perfect plush ride lol...I mean its a early 70s tractor motor what do you expect. I'd say its no worse than the 4.0 when running properly though.
I own a 1991 OM617 turbo XJ. The front sump is much more a pita than this thread makes it out to be. Even at 3.5" of lift major tackbar and steering mods must be done. You will not get good flex unless you are way up in the air or leaf sprung or something very custom (aka $$$). At that height, the power is way too low, and your mpgs suck.
With some mild tweeks, the power is tolerable. Put the 200 HP talk to bed. Most won't see 150 HP, let's be realistic. The low end is much worse than the 4.0L, so you'll need to over gear to compensate.
Again, I own one and have dealt with the drawbacks. This is in no way the best diesel available for XJs IMO. I even question the cheapest due to the sump. It is a great motor, in the right app, but I will most likely be moving on to something better suited to a SAF, coiled 4x4 with very limited room up front.
If anyone wants swap info, I have enough to bore just about anyone
One thing to always keep in mind is serviceability. Will that be serviceable?
Also, will it have a torque curve that is useful for such a general purpose vehicle. I think this specifically is where the OM617 lacks. It was great in a car. It is just fine in a pure DD. It is even serviceable at mild wheeling, but towing? Forget about it, unless you gear the hell out of the Jeep. At that gearing though, roadworthiness suffers. Your MPGs drop, and the overall usefulness declines. XJs are, IMO, some of the best vehicles due to their great balance of utilities. The engine should augment this, not detract.
I have had an old merc, and its actually still in the family at 428k & still running. I have not had one in a jeep personally, but I also know that motor very well! A stock OM617 can run to 5k, although its pointless to run it that high, power falls around 4200rpm stock.
Of course these things will never be stump pullers right off idle, or win any speed records. A stock 617, power comes on around 2600-2800 & falls around 4200rpm. But with very few mods, EGR delete, crank boost from 7psi to 10-11psi & then crank the IP, they really do feel alot better power wise & you can actually get the stock turbo spooling around 2200rpm. I cruise around 2200rpm now anyway lol, 31's & 3.55's with a 5-speed = 2090-2100rpm
Add in the W112 long runner intake to help shift the power & torque lower in the rpms. Also toss in a cheap A-A intercooler to keep the intake & EGT's down.
The IP can only support about 210ftlbs so they are limited in that since. But you can always run meth injection.
And even the swap part helps...you would need to fab up a new downpipe & exhaust. A nice 3" downpipe & exhaust will help the turbo spool alot sooner, vs the stock 2" downpipe lol.
So yes stock they aren't the best, but with very few mods, they become great preformers & will get better mileage over all.
For those curious, the W112 intake is bolt on, and cost 20 at a junkyard or 75-150 offline. Cranking up the boost & cranking the IP (injector pump) is free. A cheap & simple A-A intercooler will run you about 200 off ebay.
If you want more power & torque than what the stock IP warrants, then you can upgrade it through Myna..about 1500 bucks. Or add in a meth injection setup which will further cool the intake & cost about 200
Of course this is all on the stock turbo. You can pick up a cheap VNT turbo that will start spooling around 1800rpm, and still hold power to 4200rpm, and fall in love even more!
Like said the biggest issue with these motors are the front sump. Otherwise I think they are the perfect cheap motor for the jeeps.
Your average 4bt cost about 3k out here by me then you need a trans & the extra money to actually swap it. Your average OM617 is maybe 500 tops. Or 1000-1500 for a whole car lol. The 617 weighs very similar to the 4.0, actually a few lbs lighter. The 4bt is incredibly heavy! The OM617 has been swapped for under 1500 more than once already, and documented
The 4bt will be a stump puller, and it won't need to be geared deep at all, actually some guys try and get 3.07's to run with it to help lower highway rpms lol.
With the 617 it's best to cruise around 2300rpm.
But again I can guy a om617 for 500, or 150 from a junkyard complete! With the extra 2500 I saved, I can get the om617 swapped in and running, and have ample power for what I need!
I would never do a 4bt or similar motor swap because they are stump pullers & I'd be to damn temped in my cherokee. They will tear the unibody up insanely fast unless reinforcing is done. So far I've plated the front & the middle and will have 2x4 through the rear frame rails for my bumper mounts & thats all I plan to do.
My Jeep was a 4.0L AW4 with 3.55 gears originally. The AW4 and gearing were retained. It has about 3.5" of lift front and rear.
No amount of lift will help the track bar issue. A large amount of lift could help the vehicle get some flex without too much worry, but that front sump will always limit your upward travel, and therefore balance. In an XJ it's just WAY too much space, WAY too far forward. I have mine basically on the firewall, and it is still a huge pain. A possible fix is to swap out the stock steering pump for a really tall one, and relocate your track bar. Unfortunately, this will never result in a really nice steering setup. Not bad at all for a DD, but it will be sticking out there were you ever to wheel it. The front sump is the biggest pain with the swap. A dry sump kit would be very interesting though, but then a better motor can be had for that money.
Power can definitely be improved. It can be improved to a tasteful degree with simple tweaks. The lack of low end is rather annoying though. Again, you can over gear it to accommodate, and I'd recommend that. If you run 33" tires, I'd swap in 4.88 gears or something around there. The motor does rev up real nice, so RPMs on the high side are no worry.
One thing I did was to totally remove the Mercedes oil cooler. I converted the hard lines to AN and ran a nice cooler up front. I was of the opinion that removing as much Mercedes as possible was a good thing for simplicity and serviceability.
From experience, I can say now that the Mercedes is not the greatest choice for me in an XJ. It is questionably the cheapest route. Here in the Chicago area, the 4BT can be had for $1300 in automotive trim. A decent OM617 will run $600-800 around here. Taking into account the gearing required for decent low end performance and utility, they just about break even out of the gate. That being said, the height and weight and grunt of the 4BT doesn't seem to fit either unless your XJ is rather built. I'm of the opinion that the B3.3 or QSB3.3 are a better overall fit. The height and weight are right in line with the 4.0, and they have great low end. They will help with towing, wheeling, and net amazing MPGs (these should actually net 30+ in the real world). The sump is facing the right way, and that will allow more off-the-shelf suspension. They also have just about any power option you can imagine. The motors are on the pricey side though. They are still being produced (a big plus), and parts are a Cummins dealer away (I have like 6 in the area).
The reason I say it is questionably the cheapest, is because you must accommodate for the lack of low end torque and the sump. Also, the coolant hoses are flipped, and plenty of little stuff. All the little stuff adds up in the swaps. Up to the point where the motor itself isn't the majority of the money spent. Unless you plan on one-off fabricating everything, then plan to spend some money on this. To "just get the thing in there" would not be much money. To make it something to be proud of, it will be cheaper to go 4BT I'd bet.
I just finished prepping my OM617 to be pulled actually. I'll probably be pulling it tomorrow. I have plenty of knick-knacks to get an OM617 into an XJ. PM me if you want any of them.
My buddy has one in his YJ. At 55 MPH he gets 29.5 MPG. So yes, 30 is very attainable, if you know how to drive.
We have had a 617 at about 200 HP. It can be done.
If you can speak German, get on to Google.de and search for threads about building up the 617 and making power. That's where all the good info is about building them.
1992 YJ, 4.0 HO, 5-Speed (AX-15), 2.5" lift, 31" tires, Sony sound system, w/ pioneer sound-bar, copper-red paint, Loved it. Miss it. Sold.|1999 XJ. The "Cheep". 4.5" RC lift. 33" BFG MT. Train Horns. 2wd to 4x4 build. DD. Sold.|2003 WJ. 30" Michelin AT's. Curt roof rack. Train Horns. Stock. Soon to be lifted. DD.