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Mercedes 616/617 turbo diesel Astro build

42848 Views 237 Replies 30 Participants Last post by  tinworm
NOTE- This is an old thread where all the images were lost due to broken links to photobucket in 2017. I have attempted to go through and upload images again, but some images may not necessarily apply to posts due to lack of availability years later

I been talking about this project, and after finally finding a "decent condition" Astro, time to start working on it!

The plan is to rip the OM616 65hp MB diesel out of my old Mercedes, adapt it to a NV3500 5-speed tranny, and put it in the astro van. The engine is also being mildly turbo charged. Its not built for it heat wise, but I should be able to get away with it, and a little extra oomph on hills would be much appreciated. Searching around, I discovered that the generation 2 passenger astro is only 600 lbs heavier than the 123 chassis MB I was previously using this engine in. I figure the generation 1 astro in the cargo version is closer to the 2 ton mark. The MB is around 3700 lbs.

Ultimately, for a fun swap project i am trying to build decent MPG manual tranny diesel work van. This engine was capable of 35 mpg in the MB with a .8 overdrive, the NV3500 I think is a .78, and I have to find a GM rear end that is close to 3.46, which was the MB rear end I had ready for my car. Stock, the 240 MB came with a 3.69, but with the turbo, a 3.46 would be better. Im not sure what the 1994 Astro has for a rear end, any ideas? If its not close, I will be grabbing another rear end from somewhere, or changing the gears.

Images of what the donor sedan looks like from wikipedia, the 207D that also was fitted with these motors (about the size of a express van), and a 1989 shorty recipient van-


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yeah, it wasn't cheap, but I probably would have been out the same or more cash making all the stuff myself, so I figured what the heck. Last time I did something like this, I ended up spending more money than this adapter cost, plus all the time of making it. This way, im past that step, and my big hurdles are, get it in and mounted, and figure out the clutch.

The choice on the 616 was due to immediate availability and inexpensiveness, and its unbreakable nature. Basically I have a real soft spot for these tough little motors, and this van will be more for city type delivery stuff, so I expect the smaller older engine to excel in that role.

You guys are lucky, you have a huge amount of various diesels over there! If I lived there, I probably would have just bought a diesel ford transit van! :D
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The turbo 5cyl came with a 3.07 until 1985, then went to a 2.88. The powerless NA 4cyl has those higher ratios probably just for scooting around town, I don't think MB ever considered that they would be driven fast at all! :D With the manual tranny, the 240 is actually fairly peppy, and the older ones, which have an even slower top speed are peppier still!

I also have a 74 240 4-speed, and god forbid you try and take that thing off surface roads, its also only like 55-60 hp, but its surprisingly zippy at that, I think the rear end ratio is in the 3.9 area or something, I have to do research on that car. 0-40mph, its hard to believe so little power is available for that 2 ton car, but its more than obvious once you exit the realm of the gearing advantage!

The MB 3.46 rear end was paired with the NA 5cyl motors, which were only rated at 90 something hp, so im thinking that ratio would be good for this application turbo charging the 65hp 4cyl NA, but these are all shots in the dark! :D

Thanks for the tip on the RPO! I will check into that.
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heres what the intended engine sounds like. This is the 240 engine donor car earlier on before I retired it. (it will be quieter since this car is missing most of the floor)

Also, according to the title, this van weights 3572, pretty cool since the sedan weighs 128 lbs more!
biggreenoger said:
Hey tinworm any head way made? We have 2 diesel vans up and running on here, I've now fell way behind on my build.
switched the recipient vehicle from a 94 EXT to a 89 short body. The new van I picked up nice and cheap from a florists, they sold it because the only door that opens any more is the driver door! :D Otherwise, its pretty clean, and solves two problems, 1 the 20 year federal restrictions on repowering and registering, and 2, the massive rust repair and body damage on the other van I was going to have to do. Now I can legally retitle the van as diesel and get it inspected as diesel once im done with relative ease. Something I would have had some problems doing on the 94.

This van is a much better platform to swap into, so I stripped the 94 of parts that I might want, and sold it to a junkyard the other day. Other than that, I have been sadly remiss in moving forward with work getting in the way. I have tomorrow off though, so I plan to get somewhere on this then. (now that ive written that, I HAVE to do at least something!)

I have to strip the MB and hope to get the drivetrain out completely tomorrow. Then I can send that to a yard as well.

Any thoughts on what vehicle would be best for getting the clutch pedal out of? The local yard has quite a few manual tranny S-10s. I read on here somewhere that some GM product cars are good, but Im not sure what the best vehicle to grab a clutch out of is. It has to be a cable clutch, and aside from that, I know next to nothing about GM cable clutch setups. These astro vans are my second GM ever owned after an S-10 I had for 3 months once.
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Thanks, S-10's it is!

made some progress, engine is out of the MB, and some custom stuff has to happen with the Oil filter housing for the adapter to work. These MB diesels use an awesome toploader oil filter which I would like to retain if possible, but there is a difference between the 5cyl and 4cyl castings, so the adapter designed for the 5cyl wont work with the oil filter casting for the 4cyl. I might have to make a custom remote filter or something. Its a fairly complex part that also has an oil thermostat which releases oil into the oil cooler, so that also needs to be retained as well. Depending on the room under the hatch, I might be able to block it out 4-5 inches and keep the same casting.

Otherwise, the adapter plate fits great once the housing is removed. One other issue with crank depth to work out as well, the crank bolt flange seems slightly more recessed than the adapter tolerances call for, and the custom flywheel hits the mounting bolts. I need to use a spacer between the flywheel and crank flange, and also probably another spacer for the pilot bearing adapter once the specs have been verified for the adapter.

off to the machine shops!

Images of the engines side by side-


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id love to keep that giant filter if I can, im looking into what the pros and cons are to removing or moving the thermostat which is part of that mega filter housing. As usual, asking MB specific guys questions like that results in "you cant do anything the factory did not recommend" lectures. :icon-rolleyes: It takes a while to get some really good info and wade through the BS, that whats so refreshing about this forum actually, people are not afraid to do whatever they want with their vans, and everyone else is pretty interested or supportive, instead of telling them its a bad idea.

Im thinking I can move the whole housing to under the hood somewhere on the van, which you are right, would clear a huge amount of space under the hatch. The stock oil filter housing is great, and has a integrated oil bypass filter system already, as part of the single giant replacement element. Its also fairly clean being a toploader. It would be cool to throw a quikvalve oil drain on the oil pan, and just pop the hood to change the filter. I have the same setup on my other MB, and you can change the oil in no time, with minimal mess. This engine takes 6 quarts or so of oil. Its nice to speed up the process. The 5cyl takes a whopping 7.5 quarts, amazing considering how the engines are not all that big but probably adds something to the longevity.

EDIT- here is an image of a 616 filter housing taken from ebay, it uses a filter about 8 to 10 inches tall


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ive made some progress on this build. First, changed the recipient van, then changed it again. :D Current and definitely likely recipient is a 1989 Astro passenger that I stripped into a cargo van.

Ive also managed to put my hands on a complete astro 5-speed T5 based, and what looks like the majority of shifter and pedal parts. Ive got that trans out at a trans shop having relevant bits adapted to a T5 out of a camaro, (unfortunately, the astro tranny was blown completely). Im hoping to have that back in a few weeks.
heres the collection of parts-

2nd, ive run into some EPA/State emissions limitations, so I won't be able to actually mount this in the 89 until its 25 years old, at which point it won't have to pass state emissions tests, and I can do what I want as far as engine. Kind of annoying, but glad I finally found some conclusive information before I got the engine in the van. Realistically, I only have to wait until 2013, at which point I can get a final inspection that will push the van past the time limit.

3rd, since the time limit was discovered, i decided to get a second parts van, and tear that apart working on the engine swap on a spare subframe over in the corner of the shop. Then the whole thing can be moved over as a replacement subframe when the time comes.

With that in mind, picked up this van in the below images from another forum member, stripped the subframe for repair-

and its got some pretty expected rust issues, so ive got it at a local rust repair place being patched up, reinforced, and undercoated
worst place is right in front of the rear mount for the driver side lower control arm (pic). Guy says hes gonna take care of that, expecting it back this week hopefully. They will also be treating the interior parts with some sort of rust proofer

some images of the van and of the T5 astro specific parts-


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exciting developments-

1- Transmission is FINALLY ready. :D :D :D

So it turned out that the 1990 AstroRS T5 that I originally sourced is a single year variant of that gearbox. We were striking out finding any T5 that would accept the shifter, tailcone, and bell housing from the wrecked astro trans. It had to be a T5 from exactly the same year, and from a limited number of vehicles, IE, some of the S-10s, and some of the camaros, but not all evidently.
However, in a stroke of luck, the trans shop guy eventually managed to find a T5 gearbox out of a 90 S-10 that worked for the right price! So now I have a complete rebuilt gearbox for this project.

Everything works, it even has the right splines so I can order a clutch kit for a 1990 astroRS. (which ive done, should be in end of the week)

2- Subframe rust repair is complete, and the whole thing has been undercoated. I may try and spray some rustcheck or some such up in the internal areas of the frame, but its ready for the engine and trans to be test fitted. Once I get the clutch, I can start trying to put this together.

Next big hurdle is finding replacement clutch hydraulic parts. Every auto parts store ive called cannot find a slave or master cylinder for a 90 RS van, ill be going to the dealer to figure this out. Im sure it cross references with something else. I HAVE been able to find rebuild kits though, so I might have to go that route. I have a bad set, so they can probably get me some matching part numbers hopefully.

image of repaired subframe-


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tinworm said:
Next big hurdle is finding replacement clutch hydraulic parts. Every auto parts store ive called cannot find a slave or master cylinder for a 90 RS van, ill be going to the dealer to figure this out. Im sure it cross references with something else. I HAVE been able to find rebuild kits though, so I might have to go that route. I have a bad set, so they can probably get me some matching part numbers hopefully.
Rockauto carries them, ordered up slave and master
Some more progress-

Clutch kit came in, so using this adapter which I am extremely pleased with, hooked up the gearbox to the engine

Image below of the MB to GM pilot bearing adapter part, and a GM pilot bearing and bushing for comparison. I ended up using the bearing

The adapter goes through the custom flywheel and seats fully into the crank, as well as the flywheel. the tolerances are very nice on this part.

Clutch and release bearing installed, question on the clutch fork, is there a bushing or something that the slave cylinder fits into for the endi of the fork? The fork is a little cracked where the slave seats, and will need to be welded, but I can do that externally very easily

Here is the new engine in the refurbished subframe. I used the rear trans mount to establish just where it should be approx forward and back, and I lucked out in that the engine will not interfere with the steering links. Potential bad news is that the engine is awful high, but I might get lucky, does not seem to be that much higher than the 4.3 with the airbox, and hopefully will fit under the hatch. I also need to move the oil drain plug to the front of the pan.


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it was just pointed out to me that I will need at LEAST 5-6 inches of clearance above the motor in order to remove the extremely deep valve cover. This is to perform 15,000 mile valve adjustments as part of the maintenance schedule.

I may have to alter the subframe in order to drop the engine enough to make sure I don't make it impossible to keep in tune. That would just be annoying
Jasen said:
What about a dry sump oil pan, might that not give you enough room, or maybe reduce the level of cross member mod. you'd need to do.
Thats an interesting idea! There is a low oil pump pickup all the way down into that lower oil pan. I was reading an interesting thread where a guy cut and shortened the oil pickup. Im not sure I could make a dry sump work with the chain driven oil pump all the way down there.
Jasen said:
I've never used a dry sump. I know they make pumps for dry sump systems, maybe you can do some creative plumbing up to your pump.

Just tossin out idea after idea :lol:
Im committed now. :mrgreen:

Removed the section of the sub frame that was interfering with the lower oil pan on the diesel. The carboard piece in the background is the model of the steel structural reinforcement that will be welded to the back side of the cut. Hopefully it will easily be as strong as stock.


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Jasen said:
Are you going to infill the cut out area as well, to make it back into a box?
yeah, that will have welded vertical steel and should be a solid box when its complete, and it will be built out on the back side too, so hopefully the overall result is I moved that part of the subframe back about 6 inches without impacting the overall strength.

My only concern is how close I got to the passenger side lower control arm. I foolishly recycled the lower control arms I had with the subframe, so I wasn't able to be sure how big around they are on the back side of that bolt. I should be able to trim it though.

Next hurdle will be the steering, which the engine will definitely hit! :D
Jasen said:
Just punch a couple holes in the floor and get some rope, wrap it around the steering column,you know, rig it like a boat ;)
lol, yes, this might have to be my solution once I get to the steering.

Got the subframe back today, the guy went a little nuts with my statement "make it strong" :D

I had almost 3/4 of an inch gap on all sides, he threw so much steel on there that its awful close on the passenger side. however, he did an impressive job making it about as indestructible as you can get.


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redfury said:
I know I'm late to this game, but I'd have almost though it would have been just easier to fabricate the subframe so that it takes advantage of the void in the oil pan...instead of the subframe going straight across, have it "U" towards the back, and perhaps make a bolt on cross member for the front that could be taken off to service the motor if it would be in the way...
Moving it back was kinda what I was attempting to do with that large reinforcement to the back side. I should have made a much larger cut to begin with though, and it would not have been so close once a half inch of metal was added. :D

I was a little concerned with the possibility of flex though, since both lower control arms are exerting major force on the cross member right there as well as the stock motor mount locations. A bolt on attachement is a good idea. Im considering making this cut larger, and then I should have plenty of room. Right now its not as bad as it looks, but its defintiely tighter than I would want. These lower oil pans are constantly damaged, I want to be able to change it without excessive trouble from underneath
edgar said:
any updates?
waaaiiitting for january 2013, last gas inspection that pushes it past 25 years and emissions compliance, then I can start swapping.

Using the van everyday, can't have it off the road if I do the swap earlier.

I am considering moving the 5-speed into the van early though, the automatic is starting to fail pretty bad. Ive just about killed the transmission in this van.
FINALLY some updates-

Have my new 2 year inspection sticker! within 24 hours, van was off the road being ripped to pieces! :mrgreen:

After getting the final inspection, I was finally able to put this van in the air, and I thought it was in good shape for rust, the subframe was rusted out for the front mount locations.

4 mount locations are holding but all are rusty unfortunately. Good news that im using the other modified subframe. Ill hold onto this though, as it is pretty decent shape compared to the first one.

after the engine was out, rigged up a jig to control stock ride height and angle for the replacement drivetrain. This is specifically so I don't mess up how high the stick ends up being coming up out of the floor.

i also have some rust on the body to deal with, only part that needs fixing though, apart from some rust in the rocker that can be resolved after the subframe is put back up-

Using that jig, I set up the new modified subframe, and got the correct engine height for the diesel

Good news on the throttle, I should be able to use the stock cable throttle on the diesel without incident. Interesting, it circles around the entire engine bay, and comes around to the driver side of the engine from the passenger side. thing is about 8 feet long and will be useful for adapting to the diesel throttle linkage-

big issues to work out not resolved yet, steering and oil filter. Of the two, steering will be the number one problem here. Im toying with dropping the whole steering assembly and making the pitman arm longer off the steering boxlots of room for a remote oil filter here though, where the stock fuel filter was-

starter fits perfectly though. I was worried about the location in relation to the lower control arm on the passenger side

More updates as progress takes place now that I can actually work on this.


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looking at the rust on the upper control arms, ive decided to powdercoat upper and lower control arms, and a bunch of other bracketry as well long term.

have all that stuff off and aside, but question on the spacers for the upper control arms. Is there a spec to determine the number of spacers to include? It is just basically making sure the hubs are straight up and down? My concern is it seems like something that would be set up based on each individual subframe, but im not sure exactly how to determine the spacers I would need. I was just going to move them over from the 89 to the modified subframe, but I figured id check first with you all and see what collective wisdom there was. :mrgreen:

on another note, over 200k and endless stop start through potholes, and this 89 still has the factory upper ball joints. Goes to show what a grease fitting can do for you! shame ill have to drill them out to refinish the upper control arm

plugging away, here is my oil filter adapter plate rigged up. This will connect two lines that will run down to the oil filter which will be in either the position of the stock fuel filter, or in that nice flat bolt hole location for the auto transmission shift linkage pivot point


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