OM616 on a test stand - PeachParts Mercedes-Benz Forum

d!0+]@9$f3>yEI$Il3ZQ · #1 08-26-2021, 11:33 AM

So I bought a 616.916 with manual transmission, I've never owned anything like this before so there are lots of new things to become familiar with. I intend to use it in something like a Model A speedster but I'm still looking for a chassis to start with. In the meantime I want to get the engine running well.

It came from a W115 that was being swapped to a 2JZ, owner said he drove it for a while with the 616 and always wanted to swap it. So when the starter failed he pulled the whole thing out and started the swap rather than fixing it. I have not tested the starter to confirm.

I built a test stand for the motor, just waiting for motor mounts to arrive so I can finish it up.

I've been looking over everything and I was hoping you guys could help answer some questions I'm having a hard time with, since I never had a whole car some things are just unclear when looking at this.

1. Where does the valve cover breather tube connect to? On some pictures I've seen it goes to the fitting on the bottom side of the intake manifold, but there is no where for it to go on mine and I don't have the tube itself.

2. What are the bolts on the intake runners for?

d!0+]@9$f3>yEI$Il3ZQ · #2 08-26-2021, 11:41 AM

3. What size bolts should fit into the front of the head? I normally work on Japanese stuff so I have a big bucket of random fasteners and nothing fits. Is the German stuff a different thread pitch? Or do you think the threads in the head may be messed up? How many bolts should the water pump have? I see some extra holes that don't have bolts in them.

4. Where should the vacuum lines be plumbed to from the vacuum pump? One goes from the intake manifold to pull fresh air? And the other? I assume some sort of vacuum manifold would have been used to distribute vacuum to multiple places in the car? Can I send this directly to a brake booster if I use power brakes? If I don't use power brakes I assume I can just remove the vacuum pump altogether?

5. How is the fuel cutoff arm operated? Pull back/up? What is that rubber mount for? Can I get rid of the mount?

d!0+]@9$f3>yEI$Il3ZQ · #3 08-26-2021, 11:48 AM

6. Can I block off the heater core water outlets on the side of the head and water pump if I'm not running a heater?

7. Are 3 points of support enough for engine and transmission? I see some other brackets on the bottom of the engine and transmission but the only mounts I found for sale were 2 on the engine and the one on the tail of the transmission. Just want to make sure I'm not missing anything I need.

8. Is it common to have part numbers starting with 615 on parts on the 616 engine? I assume these are just leftover from the previous OM615 in the W115, and when Mercedes changed over to the 616 they didn't need to change any of those parts. Or do you think this 616 engine was swapped into this car at some point?

9. Does this engine have 2 water temp sensors? I see one at the thermostat housing, at one on the side of the head?

d!0+]@9$f3>yEI$Il3ZQ · #4 08-26-2021, 11:53 AM

10. Do the throttle arm pivots look bent to you? Or are they supposed to be like that?

11. Do I need the throttle butterflies in the intake? Could I remove them and use just a single arm from my throttle pedal to the injection pump? I've seen some other cars without them and I'd much prefer not to have all those pivots and rods running everywhere.

Anything else you can see on here that I should know? My plan is to do the bare minimum to make it run just to make sure it's worth working on, then I'll do all the maintenance on it, oil change, fuel filters, valve adjust, tstat, etc...

d!0+]@9$f3>yEI$Il3ZQ · #5 08-26-2021, 11:54 AM

Wow, that turned out to be a lot. I had to split it up due to the photo limit. Let me know if you guys want to see anything else.

resago2000 · #6 08-26-2021, 12:24 PM

you have a vacuum operated pump, do not remove the butterfly valve or the pipe running from the throttle to the pump.
the rod connected to the pump is only the idle damper, and can be removed if you want, just helps smooth low idle

heater pipe nipples can be removed AFAIK

the engine gasses where just piped into the intake before the butterfly assembly. can also be vented to outside if you dont care about certain things

water sensors, the one in the head is temp, the one on the coolant neck is a switch the triggers the aux fan

the vacuum pump, vacuum is on the port currently without the hose, the vacuum pump expels air in to the intake.
you dont really need a vacuum pump in the case, personally, I would get a block off cover and use an electric setup, just my opinion though

the large bolt bosses on the front are where the huge AC bracket would attach

d!0+]@9$f3>yEI$Il3ZQ · #7 08-26-2021, 01:59 PM

I added numbers for the questions to make it easier.

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