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The XJ Mercedes turbo diesel conversion forum

badgator

NAXJA Forum User
I bought a 85 MB 300sd 6 weeks ago 125 hp/170 # torgue(which I love driving, gets 25-30 mpg 3800? lbs) , now my XJ runs like crap I want to install a mid 80's 5 cylinder MB turbo diesel in my XJ. I have researched this for more than a year, as there are a couple running examples BUT nobody sells an adapter or kit. I found another MB turbo running good for cheap - donor. I also built a WVO centrifuge to burn WVO in my diesel(s)!!!
 
I seem to recall that there was an MJ out there with a Mercedes 300TD in it. However, the MJ was 2WD as the oil pan on the Mercedes engine wouldn't clear the D30 found in a 4WD model. IIRC, the MJ in question was destroyed in Katrina but some searching should turn it up.
 
casm said:
I seem to recall that there was an MJ out there with a Mercedes 300TD in it. However, the MJ was 2WD as the oil pan on the Mercedes engine wouldn't clear the D30 found in a 4WD model. IIRC, the MJ in question was destroyed in Katrina but some searching should turn it up.

had it bookmarked.

I am doing all sorts of diesel swaps in my head:shhh:

http://www.naxja.org/forum/showthread.php?t=57574

if your into the benzo diesels here is a cj8 with a merc 2.9 http://www.cookbros.com/mbz.html

ask around on here and see if they are of any help http://messages.jeep2diesel.org/
 
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motorcityxj said:
had it bookmarked.

Awesome. I always liked the job he did on that, but sort of just filed it under 'neat' and forgot about it since it's 2WD. A shame, too, because there's no shortage of those 300TDs around here and they go forever if looked after properly. Power output's not too bad for an older diesel, either.

I am doing all sorts of diesel swaps in my head:shhh:

Me too ;) The 2.8CRD coupled to the 545RFE looks like the best but most expensive bet: given the roughly 700lbs. of weight that a KJ CRD has to carry around that an XJ doesn't, performance should be pretty cracking and a fully-optioned CRD only weighs around 60lbs. more than a 4.0.

A 4BT might also be doable, but I'd really like a more modern unit in there (not that I have anything against the 4BT).

Just mentioning the diesel engine swap matrix for the benefit of the search feature; it can be found here.
 
My exhaust is all but done, as I already have 2 1/2" with a hooker aero muffler. Mating the turbo downpipe to the ex should be EZ as they are both on the same side.
 
I have been researching this and other jeep/diesel conversions since at least May 06 - more likely 05 and well over 100 hours searching the internet. Decided to go with Mercedes 5 cyl turbo. For longevity and cost. Luckily my Jeep engine problems are not as bad as I thought so I can start the conversion with minimal stress - on me! A ex coworker offered me a new 3" Rough Country lift kit for $200 - needed for oil pan to front axle clearance.
 
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Also keeping AC/ALT/PS/Oil Cooler from Mercedes, Alternator brushes and regulator is replaced with 2 bolts on back of alt, $35? at Autozone. Uses GM AC compressor (I live in FL). PS pump even has built in filter. Oil cooler is mounted vertically next to radiator about 16" tall.
 
My 85 Mercedes 300sd 4 speed auto NOT overdrive, 2.88 rear end ratio - VERSUS - 89 Jeep Cherokee limited AW4 overdrive 3.55 rear end ratio (I'll keep the AW4). The MB powered XJ should be quicker (compared to a 300sd) AND get more MPG, BUT a 300sd has a lot lower drag c/e. Note - on this diesel when you kicked it down turbo lag is AT LEAST 2 seconds, before it starts spooling up, in traffic you have to kick it down way ahead, OR sit and wait!!! Once it starts getting boost pressure it builds quickly(to 10# on boost guage). This is my first TD, my 3rd turbo.
 
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badgator said:
My 85 Mercedes 300sd 4 speed auto NOT overdrive, 2.88 rear end ratio - VERSUS - 89 Jeep Cherokee limited AW4 overdrive 3.55 rear end ratio (I'll keep the AW4). The MB powered XJ should be quicker (compared to a 300sd) AND get more MPG, BUT a 300sd has a lot lower drag c/e. Note - on this diesel when you kicked it down turbo lag is AT LEAST 2 seconds, before it starts spooling up, in traffic you have to kick it down way ahead, OR sit and wait!!! Once it starts getting boost pressure it builds quickly(to 10# on boost guage). This is my first TD, my 3rd turbo.

according to that link from CASM the benzo diesel has 84 hp and 140 lb/ft of torque. Is yours painfully slow ?

My diesel swap idea is a rollover or theft recovery tj unlimited, with a mildly modded cummins 4BT1 125 hp 280 lb/ft, or the cummins isb 3.9 which is 170 hp and a whoping 420 lb/ft if i can ever find one at a half decent price!

the runner up conversion (and very very distant second place) am gonna put a vw turbo diesel in a flat fender or a suzuki samari.
 
0-60 times are about 15 sec. 50 - 75+ is pretty quick. Turning left in traffic sucks as you have to plan ahead with 2-3 seconds of turbo lag. This can be adjusted out (ALDA) and boost pressure increased to get 0-60 near 10 sec. I bought a adjustable boost controller off ebay $10 2 weeks ago, but with current Jeep problems I decided holding off playing with the injector pump/ALDA and wastegate for now. 84 hp = No Turbo. 4BT would be nice but low rev limit, more vibration and a lot more weight to deal with.
 
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How about a GM 6.2L diesel?
 
badgator said:
I'm guessing you could use a gm to jeep adapter which is readily available, if the 6.2 is about same size as a SBC.

exactly what i was thinking

I had an FSJ that I was toying with the idea of a 6.2 swap, they're about the same size as an SBC, use the same mounts, so they should fit in an XJ. 6.2's are very common in the millitary surplus world, and therefore pretty cheap to obtain.

More power? Throw on the turbo kit from the 6.5L.

Bolt it up to a TH400 and you're good to go.
 
badgator said:
I've seen many 6.2 on govliquidation.com? AND Jeep aircraft tugs (cj10) -come with 6 cyl nissan? diesel, but use 727 trans.

the CJ10 tug motor is another good option, IH used it as well. Alot harder to find than the GM CUCV diesel
 
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