Mercedes 616/617 turbo diesel Astro build

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.

Just an aside about how long Mercedes diesels last:

When I lived in Cordova, AK in 1972-73, the Troopers told a friend that his 1955 155D was no longer street legal because the fenders were so rusted away that the headlights pointed down.

So he pulled that 155D engine out of the rusted hulk of a car that had 520k miles on it. The only service to that engine was having the injectors cleaned once in Whitehorse YT when he got some dirty fuel along the Alaska highway sometime in the late 60s.

He had an adaptor made at a local machine shop and pulled the GM V6 from the outdrive of his 28 foot aluminum bowpicker gillnet boat, and installed the 155D engine.

He ran that engine which already had over 520k miles on it every fishing season from 1973 to 1997, when he quit fishing and sold the boat. He told me that it was still running in 2008, 35 years(!) after it was moved to the boat!

If Mercedes made a smaller version of the Sprinter, that would probably be my next taxi van --- but I'd run it on biodiesel!

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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

couple small setbacks, but maybe with a silver lining. Ive been busily plugging away at disassembling, cleaning, and trying to recover as many bits off the stock suspension I can.

The original plan was to do all new control arm bushings, ball joints, ect and use what was on the van as far as major components.

I had removed and dropped off 4 upper control arms (off two vans) and one of the lower control arms so far to be sandblasted. Was still working on the extremely bad driver side lower control arm bushings off the 89.

Powdercoater called and said of the 4 uppers, he thinks only one is worth coating, so much rust flaked away that he thinks 3 at least are paper thin if I were to sandblast them all completely. He did a couple sample areas.

Meanwhile, in trying to press out one of the bushings on the lower control arm im still screwing with, the rust was bad enough that I managed to crunch the whole dam thing, splitting the entire area I was trying to press the bushing out of.

so, in the end, I have a rusty passenger upper control arm, and a rustier passenger lower control arm, out of 6 (actually 8, two lowers off parts van were scrapped, too rusty) originally.

Went on the internet, and discovered I can get brand new upper and lower control arms for about 100 bucks a pop that fit this van, so gonna do that. Come with ball joints and bushings installed. Love working with domestic stuff.

Also have to get a replacement sway bar, original is strangely cracked on both sides lengthwise. 100 bucks brand new also, comes with links and mounts.

some updates-

Received my new control arms, and ive reassembled the entire suspension with a lot of new parts.

I got the upper control arms from mevotech, and the ball joints were questionable, so I swapped them with moog, and lower control arms from dorman, which looked pretty good.

so now using that metal bar to establish a centerline, ive got some numbers to work with.
This is the principle issue. The diesel engine is a grand total of 27 inches tall, oil pan to valve cover, BUT, the valve cover itself is a whopping 6 inches tall, and needs that much clearance above in order to fully remove it and adjust the valves.

Measuring up, I have a ballpark measurement of about 24 inches from the subframe up to the top of the engine compartment, including about 1 inch of stock bushing. Below the centerline, I have about 5 inches of space before interfering with the steering apparatus.

So basically using the 5 inches as a locked in point to use the stock steering linkage, if I installed the engine with the stock subframe bushings, im looking at a total space allowance of 29 inches, and only 2 inches of clearance above, which would never work. The engine would fit, but I wouldn't be able to service it.
with a 2 inch lift, total space would be 31 inches, and 4 inches of clearance
3 inch lift, total space 32 inches and 5 inch clearance
4 inch lift, total space is 33 inches, and would give me the 6 inches above clearance.

So my plan now is to go with huge 4 inch subframe spacers, and compensate on ride height by possibly cutting down the springs by 2-3 inches or so to drop the van back down. This way I get a little bit of lift overall from the outside, but the larger dimension I need inside the engine compartment. what do you all think? It will be kind of weird, as ill be lowering the van at the same time as raising it, but theoretically, it should work. This leaves me with extending the steering shaft in some way as my principle remaining steering issue.

so some small project updates-

for the pipe lift, I decided things would be way easier cutting if I did square pipe instead of round, so I used some 4 inch square instead. Just have to finish welding it up, but everything is tacked.

sizing the square stuff, went with a 3.5 lift

a great development of raising the motor up that far is I think I can use the stock MB engine mount arms and mounts, which have a built in provision for the shock. Working on a few adapter pieces of steel to mount the shocks to the frame.

Meanwhile, ive got the body back down near the ground and ive been stripping out all the A/C stuff and other gasoline incidental stuff, like the ECU ect. The plan is to get the clutch pedal in, pivot worked out, and be ready to do the hydraulics as soon as the subframe is mated back to the engine.
taking some time, but slowly coming along.

no worries, I think I asked the same question a couple times! I need to reread the thread more often to avoid that!

In sourcing the 5-speed, the guy also sent me some unobtanium stuff like the stock shift boot and some trim and sound insulation pieces, cut out the stick location. The boot is totally usable and can be cleaned up.

Meanwhile ive been playing with the clutch issues and how I want to proceed. I do have a stock clutch pedal that will supposedly fit under the dash. The problem with this is that the firewall and pivot points were reinforced on the 5-speed optioned vans, and id have to reinforce the firewall on this van evidently.
Ive subsequently learned that the firewall apparently flexes on application of the clutch if it isn't reinforced.
At the same time, I have to drill out some totally inaccessible horizontal holes and get some unobtanium bushings to fit so the stock clutch pedal will pivot which is piling up into something that im not excited about since the pivot point metal also looks pretty thin anyway.
Instead of all this, im thinking of going with a floor mount pedal.


some wiring stuff im looking into to now. I intend to remove the engine computer completely.

in the engine compartment, this whole bundle of wires at position 2 goes only to the ECM, except one which controls the door switch on the passenger door. Im going to get rid of everything apart from that one wire.
At position 1, I have the correct plug that screws in, so from there I can run my relevant wires to the diesel setup and make it look factory hopefully


Over on the drivers side, there is this control box which apparently controls only a brake proportioning valve, and the variable wipers. Im hoping that it doesn't need the ECM for any reason, and i can just give it 12 volts to continue working correctly. Ive been looking in yards for something from a similar year astro, there are no identifying numbers left on this thing. Anyone have any advice on the function and description of this unit? I need to figure out what it does

Here are the finished position wise motor mounts. (later once Im satisfied with them, Ill take them off, do some finish grinding/welding if needed, and powdercoat them, and the driver side still needs an engine shock). So after waffling deliberation, I decided to go with the GM mounts because they are so much easier to remove, especially with the engine being in a van body and accessibility maybe being an issue for something like the mounts.

The engine now sits with excellent clearance over the steering control arms. I have a high lift overland vans steering column connector coming which will compensate for the big lift on this subframe

a lock to lock test of that engine height looked good for steering interference. Though I did discover what looks like a bind issue with the tire hitting my aftermarket replacement sway bar, that might be a problem later. The bend is different than the OEM swaybar

I used a pair of pallet jack wheels approximately the same height as the subframe lift to space up the transmission mount as a temporary solution.

part 2-

Reinstalled the subframe, the stock MB fuel filter head needed to be removed.

Luckily once mated, the only interference are these brake lines! If the engine went any higher, id have some issues with the MB power steering pump hitting the GM brake booster

From the inside, everything lines up nicely, the stick handle is just a tiny bit to the rear, but still came right up to position. The engine will definitely fit under the hatch without issue, and it looks like I should have no major problem removing the injection pump if I need to. The access actually seems better than in the 240 in some areas-

On the passenger side, looks like there should be just room for a turbo, but exhaust clearance might be interesting.

Up front I can use either the GM or MB radiators, actually both are very new. Lots of room up here fortunately.

there is just room to get the cover off! Huge hurdle jumped with this development. It has to be pulled into the passenger cabin to clear the front, but it comes out without too much difficulty, so i will have to remember that when im routing lines later.

On the subframe, I had some concerns since this was a rusty subframe originally out of a later van, I was worried it might not fit right. Fortunately 5 out of 6 bolts fit perfectly. One is totally off, by maybe 3/4 of an inch. I also stripped the thread on that nut as well (I had threaded it first a little, and once the others were in, that bolt got so jammed it ripped out the threads)
Fortunately for me, its just about the best place for this problem with plenty of access. God forbid it was a center bolt. My plan is to open up the unibody above, drill up through the body using the bushing as a guide where it actually sits, and weld in a new nut in this new position, then close up the unibody.

Thanks! looking to get this done/movable soon hopefully, need the space for another car

Image below of the radiators compared- MB on the left. The ports are in the right place apart from the difference of side to side vs up and down flow.

Amazingly, the stock astro upper hose fits perfectly if you cut off about 2 inches. The stock Mercedes lower hose fits with about 4 inches removed. There might be a reference issue with the fan for the lower hose, and Im missing a lower plastic shroud that I definitely need that should solve that problem. The fans almost fits in the shroud correctly, just about 1 inch over to the passenger side. Also I had to trim a one inch strip off the upper shroud to clear the power steering pump

the only thing left is a rear port that needs to go to the heater core. The plan is to fabricate a pipe passage that bolts to the top of the valve cover and gets the coolant line past the turbo exhaust area without getting too close.

Excellent development on the throttle. Due to some amazing coincidence, or just a standard hole size that all automakers make for these things, the astro throttle cable fits right in perfectly to the Mercedes cruise control cable attachment. As if it were made for it. Some heavy modification to the throttle will need to take place here, as the distance is quite a bit different for cable throw, but I can use the mercedes bracket for the custom mod

ok, Ive taken care of the cooling system and its all hooked up ready to test. I had this steel coolant pipe on the shelf, and I made some brackets for it to fit on the valve cover, so it can run from the right rear of the motor up above the intake and cross over to meet the GM heater core.


Meanwhile, fitted the turbo. For the first time, the fact that this is a van came home to be big time. The turbo is really heavy and difficult to install from this angle, and the edges of the hatch might as well be a knife! The good news is that if fits in the space nearly perfectly, the bad news is that an exhaust pipe wont. Ill have to modify the downpipe or the hatch/body a slight amount to get the clearance I need.