Mercedes OM617 5 cyl Turbo Diesel engine swap to Jeep Wrangler YJ conversion
 

Here are some updated pictures of our Mercedes OM617 going into 1995 Jeep Wrangler YJ with AX15 5 speed manual transmission. Not running yet I decided on 4" lift kit to help clear the MB oil pan. #1 is MB crankshaft to flywheel adapter. #2-3 is the adapter bolted onto stock Jeep flywheel. #4-5 is the OM617 engine to AX15 bellhousing adapter plate. #6 is with the flywheel and clutch mounted. #7-8 is AX15 bolted to MB OM617 engine. #9-10 is the engine installed in YJ waiting for motor mounts and some diesel. We are making motor mounts tonight and hopefully starting on accessories. It sure was helpful to see what the other guys did to make this swap. My son already is wanting to build our 2nd diesel wrangler, since he already has MB that runs on waste vegetable oil.

Sweet :tu:

LOOKS AWESOME....
 

I Am going to do the same thing, 1985 mercedes 300td into a dodge truck with a AX-15 Transmission... did you buy the conversion kit...if so where... IF NOT...Dang!!!:jump:
one of the concerns I have, someone on another post said they did the same thing(300td to AX-15)...and they could not use 5th gear due to the gear ratio...I am not sure what he ment by that, It seems with the torque the 300td puts out, It should be able to use 5th...
Have you heard of that??? he said he got 28- 32 mpg... but i guess thats with out 5th gear ... Please keep us posted...thnx

Welocme to the club! I love my om617 in my cherokee, even though #5 is down 100lbs. I should have the replacement motor in next week. As for 5th gear, you just have to gear the axles correctly, this motor loves to rev. I have 30's with 410 gears and od is used mostly for freeway, it loves 70+mph. Nice work on the adapters!

Thanks for comments. It was not a kit, but i will probably make another one soon for my son. I am very fortunate to work with some guys who are in drafting and engineering, plus the company has a large machine shop. Once the autocad drawings are double checked these would be easy to make again.

Hey kellymctampa-
don't believe everything you read!
I have the stock Jeep Cherokee Diesel with the 2.5 engine equipped with the AX 15.

Why shouldn't the AX-15 fit? It does fit very well. Forget about the extreme mileage- if I go like grandma with stock street tires I get 28mpg. But that does not include any fun and you will experience fun!

The OM is a very good engine! Thats for sure and the AX15 is reliable enough to hold the torque too.:rocking:

Lift and the motor mounts are in. It moved!!! Forward & backward last night. Power steering is working and glow plug relay is wired. Still working on a electric over vacuum fuel shutdown, anybody done that yet? We will be taking more pictures soon. :jump:

I'm doing the same swap on my Comanche. How was the adapter? It looks like you did a great job with it, very clean install. If you make any more i would certainly be interested. :tu:

~Dave

I used the boost overide switch out of the Benz, 12v to the switch closes vacuum, off opens vacuum circut. I used the 12v that went to the coil.

any chance of buying a set of the adaptors??

I can have more adapters made at my work. They cost about $340 dollars for the set, 1 crankshaft to flywheel adapter with machined pilot bushing and 1 engine block to bellhousing adapter. Thanks for tip on fuel shutoff i will try that this weekend.

Sign me up!!

Just for the sake of curiosity, what is the weight difference between the MB flywheel & the Jeep? I know the Jeep wheel must be retained, but I was curious if the Jeep wheel was significantly lighter than the MB wheel if there may be some vibe's...

Either way i am going with this same setup, let me know how to contact you please.:c:

I tried to send you a private message did it show up in the right hand corner when you logged back in? Im new to how these forum websites are supposed to work... I will weigh the flywheels i have an extra from a transmission i bought.

No, we have to have 10 posts before we can PM.:booo:
I already get a butt load of spam, so what's a little more?

E-mail: stephen_310@yahoo.com

Really cool swap, nice work!

Went on maiden voyage tonight 2 miles, running real good alot more power than i thought. Trying to have everything ready for PA state inspection by Tuesday! Thanks for vacuum switch idea it shuts down nice....:tu:

Great news! I wonder sometimes weather those hp & tq numbers in the book are really what these motors put out. They seem to perform alot better than those numbers would suggest, and I haven't even turned anything up yet!

Videos!

Passed state inspection...:jump: Went 4 wheelin did great in the mud and had a chance to pull 3/4 ton chevy out of a mudhole. Definatley put the crankshaft adapter to the test. Took Jeep to Fall show at Carlisle PA last weekend, had a lot of people looking. I have 276 miles on swap now with no problems.:rocking:

Sign me up for a kit. I doing the same conversion you did. How do I contact you. Thanks

I am so impressed, to where I want to purchase an adapter, .... so you keep the mercedes flywheel on and you bolt the AX-15 flywheel to it....keeps the balance.. (cures Mercedes vibration problem)and you keep the mercedes starter)....I likeeee!!!!
Do you know the rear end ratio++(tire size).... how fast...MPH...will it go.... I know since your mudding.... MPH, doesn't matter.... I'm putting it in a Dodge Dakota, daily driver.....would really love to get 75 mph...:):)...let me know if I can purchase an adapter...Great Post!!!...:):)

---AutoMerged DoublePost---

I apologize for ...double posting... what year....what engine came out, of the jeep...4 CYL....inline 6...V8...just for purchasing a trans+bellhousing+flywheel...INFO......:)

IIRC the AX15 is found only behind the 4.0 (and the 2.5 diesel but that doesn't count since it's a European version). So your best bet would be to find a 4.0 manual to scavenge for parts. And I believe you get the NP 231 t-case, which is better than the NP 242.

to be exactly:
NP 231 1,885 ft lbs max torque
NP 242 1,486 ft lbs max torque( I do like the permanent 4wd option even if it is weaker)

what starter did you use with this setup

We are trying to funnel inquires through a website my son and I are working on click here >> Home <<:hellox: (We can't private message on this forum with out a certain # of posts) The website is not finished but has more information on our conversion and pictures. We have an email address of: sales@MercedesDiesel4x4.com Our adapter does not use the mercedes flywheel. One side of the adapter bolts to the MB crankshaft and the other side bolts to the stock 4.0L Jeep flywheel. We use the stock AX-15 bellhousing from Jeep as well as the stock Jeep starter motor. I have ordered 3 more sets of adapters from our shop but they will not be done until 2nd or 3rd week of November, they are very busy this time of year. We thought the safest way to purchase kits might be to post on ebay with a buy it now price?? Hope that answers everyones questions for now.

Thanks for your response. I think Ebay with buy it now price will be safe for both parties too. Please post a link when you have it listed on Ebay. How is your Jeep running? Is the power adequate for the Jeep.Thanks

Power is more than adequate in my Cherokee with an auto, with a stick even better! All I have adjusted is the alda.

Checked the mileage today, 22.3 MPG running hard and with 33 x 11.50 tires. I may put set of stock tires on to see how much more MPG i could get. It does 65-70 smoothly in fourth gear on the highway. Without going to 4.10 rear gears or changing tires, i don't see being able to use 5th gear. :humm:

What gears do you have now? I'm guessing 3.07 or 3.55. I'm going with 4.10's in mine from the start & also plan on using 33'' tires so that's good news for me!!:jump:

i have the stock 3.07 for 4.0L 6 cyl. but my son told me the 2.5L 4 cyl. had 4.10 from factory. I cant decide to run normal size street tires for everyday use, or get a set of 4.10 rears to keep my 33 x 11.50. The Mercedes donor car also originally had a ratio of 3.07 in the 300D.

That is correct if my memory serves me right :)

That is correct the 4cyl came with 4.10s, great build up looking forward to some more pics. :tu:

Actually the 2.5L 4 cyl with the A904 automatic came with the 4.10 gears, and as far as I've been able to determine, it was the only model XJ that did. The 2.5L 4 cyl with the 5 speed came with 3.54 gears - as did the 6 cyl with the auto. The 4.0L with the 5 speed did come with 3.07 gears and so did the MB 300D automatic.

HOWEVER, the AX-15 is a 5 speed with a 3.83 first gear, a 1:1 fourth gear, and a .79 OD 5th gear. The MB722.3 automatic tranny is a 4-speed and has a 3.68 first gear and a 1:1 fourth gear. So the AX-15 has a slightly lower first gear, but a significantly higher high gear (5th). That's why 5th isn't very useful - its out of the range of the powerband of the motor.

The other adjustable factor is the tire size. The stock tires on the MB are 195/70/14"s - roughly 25" in diameter. The stock tire size for the Cherokee is 215/75/15"s or 225/70/15"s - roughly 27-1/2" in diameter.

The slightly lower first gear of the AX-15 will just about compensate for the larger stock tire size, and let the engine use 5th gear under flat smooth highway cruising conditions only. With the 33"s and stock 3.07 axle gears, 5th will be useless and even the lower first gear of the AX-15 isn't enough to give you the same acceleration in the Jeep as what it gave in the MB 300d either.

Put some 3.54 axle gears in it and 5th still probably isn't going to be very useful with 33" tires. Maybe with a set of 30"s or 31"s, but not with 33"s.

I think you pretty well hit the nail on the head. The only way you're going to get to the point of making 5th gear really useful is with a set of 4.10s...

I have 410's and 30in tires, the tallest tire I belive you can use with this motor, gear,and od. I an toying with switching to a 29in tire to get it in the "sweet spot" more often. I am finding that in 5th and locked up down the freeway, anything below 60 and it will bogg down and want to downshift. It really LOVES 70+ and doesn't even start to run out of power above 90. So I think a set of 235-75 15's would be perfect, and I think my mileage will go up as well(it's @ 25+ mixed running hard)

2.1 Diesel came with 4.10's too. And possibly some cars with towing package or off-highway package.

Seems normal for the 5th not to be useful compared to 4th in the Mercedes. It's overdrive, a more honest comparison would be with 4th in the ax15.

Ignoring the difference in gearbox ratios, going from 25" tire and 3.07 to 28" tire on the Jeep, 3.54's would be a good match.

Don't worry about the gears.
There are some Cherokee Diesels with 31' and bigger tires rolling around in germany. Of course you will lose a bit of bite. But you won't recognize after a while getting used to it. Most drivers with 4.10 claim to loose to much mpg with too small tires on the Autobahn. so 31 and bigger will be fine.

Correct me if I am wrong, but those euro Cherokee's aren't running OM617's, so they may act a little different. No way could I get away with anything larger than 31's unless I was planning on driving 80+ all the time!

Hmmn, according to my research the 2.1 diesel came with 3.55s too, but since I've never actually seen one so I can't say for sure. They are so rare that they aren't even worth talking about anyway, since finding one is almost impossible. There was one engine/tranny combo that came from the factory with 4.10 axles - the 2.8l V6 with the manual tranny - also a fairly rare combo.

Yup, I agree with that.

New Pictures
 

Here are some updated pictures. We need a paint job now. We have 3 more sets of adapters being made and 1 commited.

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We are working on technical page on website to assist others in conversion. See web site OM617 Mercedes Diesel Conversion Jeep Wrangler YJ Engine Adapter Swap by next week.

Very nice!!