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I recently installed a 1983 OM617 into my 1982 Jeep Scrambler. I'm running a T-176 4 speed trans, 4.10 gears and 33 inch tires. In 1st and 2nd gear the Jeep pulls fine and seems enjoyable to drive. As soon as I put it in 3rd it falls on it's face at the slightest hint of a grade. I'm getting passed by Yugos! I don't have a tach installed yet, so I don't know what RPMs I'm pulling when this happens. According to my boost gauge, I'm pulling 6 to 10 lbs of boost in first and second, but almost none when the RPMs fall once in 3rd. I have yet to sniff 4th gear. Currently the motor is straight-piped w/ the stock MBZ exhaust pipe at 2 1/4 diameter. I've done and EGR delete as well. I ran a purge using the Liqui-moly and the idle is smooth. Temps over around 185 to 190 w/ the temp sender mounted in the engine block. There is some oil leakage in the turbo, so I'm sure new seals are needed, but since I'm making boost, it's going to have to wait.

So far I'm very disappointed inn this swap. While I enjoyed doing the work, the results are far from acceptable. Any ideas on what to look at will be appreciated!

IMG_2124_zpszglfzc5o.jpg
 

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I recently installed a 1983 OM617 into my 1982 Jeep Scrambler. I'm running a T-176 4 speed trans, 4.10 gears and 33 inch tires. In 1st and 2nd gear the Jeep pulls fine and seems enjoyable to drive. As soon as I put it in 3rd it falls on it's face at the slightest hint of a grade. I'm getting passed by Yugos! I don't have a tach installed yet, so I don't know what RPMs I'm pulling when this happens. According to my boost gauge, I'm pulling 6 to 10 lbs of boost in first and second, but almost none when the RPMs fall once in 3rd. I have yet to sniff 4th gear. Currently the motor is straight-piped w/ the stock MBZ exhaust pipe at 2 1/4 diameter. I've done and EGR delete as well. I ran a purge using the Liqui-moly and the idle is smooth. Temps over around 185 to 190 w/ the temp sender mounted in the engine block. There is some oil leakage in the turbo, so I'm sure new seals are needed, but since I'm making boost, it's going to have to wait.

So far I'm very disappointed inn this swap. While I enjoyed doing the work, the results are far from acceptable. Any ideas on what to look at will be appreciated!

View attachment 122617
You are going to need a tach to know your RPMs, I suggest

https://www.tinytach.com/diesel-tinytach

My "guess" is you hit 3rd gear with the turbo not producing boost, and do not have enough power (torque) to get the engine speed fast enough to make boost.

Also have a vague memory that there is a big gap between 2nd and 3rd gear - some one else might have more real info on the MB engine.
 

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You may be onto something. I did some reading and it appears that if I drive it like the old motor then I'm going to have these issues. I took it out again and ran the same loop as before only this time I ran the RPMs much higher than before and it performed better. I'm going to have to do some more driving to get used to the different power delivery. I know that my turbo is leaking oil so I don't know if that has some impact on the performance, but when I take off the downpipe there is noticeable oil collected, not to mention gray smoke from the oil in the exhaust. I'm going to order a rebuild kit for that and see if that helps. Thanks for the tip on the Tiny-Tach. That looks a lot simpler than some of the alternatives I've seen.
 

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Peak torque is at 2,400 for a stock OM-617 so you would be better served with a close ratio trans the AX-5 or NSG-370 would be a nice fit go to http://www.grimmjeeper.com/gears.html and crunch the numbers getting the right gearing is key to driveability when you do a swap.
 

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The om617 is designed to be a very high Reving diesel... up to 5000 rpm however torque is lacking , will have trouble pulling big tires and/or large ratio trans , cummins make torque right off idle , not so with the Benz , they tend to be kinda doggish until they are wound up then they roll, remember they were designed for highway cruising , which they do well .... off road best to have a lot of gear and tight ratios ... I love mine but it’s a cruiser to work , highway trips etc... and the y are limited in mods to help them out ... but they are a solid engine so long as u know there limitations ...
 
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