Parts needed for 617 turbo replacement?
 

I'm getting ready to pull the trap cat on my '85 300D and have a local machine shop make me a "test pipe." Since I've been unable to find a spare trap cat to have converted, I have to take my car down for however long it takes the shop to do the job. The shop will bolt my trap cat to a jig, cut the "football" out of the middle, and weld some exhaust pipe in its place. Before I begin, I want to make sure I have all of the parts necessary to put the engine back together. The turbo has to come off in order to get at the trap cat and I'll pull the manifolds for cleaning while I'm at it. The turbo itself and all of the intake and exhaust plumbing is in good shape, IMHO, and won't need to be replaced, just R&R. I'll use PB Blaster and lots of patience to reduce the chances of snapping a stud.

I bought a "turbo mounting kit" (617 090 06 80) from FastLane; it has a manifold gasket, turbo gasket, oil line seals, intake o-ring, etc. It looks pretty complete. I even bought an exhaust seal ring (107 492 14 09) that goes between the exhaust manifold and the trap cat although I probably won't need to use it. My question is, while I have the right side of the engine bay torn apart, is there anything else I should check or replace?

Jeremy

starter... alternator... belts... hmm... if you live in a cold climate this is the perfect time to install a block warmer...

This based on my experience on an 82 300SD (same engine/turbo:)

- EGR gasket if you're removing the EGR valve from the intake manifold
- O-rings and large bottom grommet (at entry to top of oil pan) for oil drain pipes from turbo and air filter housing
- make sure the "turbo mounting kit" has oil line seals (gaskets) for both top and bottom of turbo
- both large rubber seals for U tube (if they're hard or leaking at all)
- (if needed) 3 rubber air cleaner bracket mounts and heat shields
- (if needed) motor mounts and (if you have them) engine shocks

The bottom two bolts holding the turbo onto the exhaust manifold are very difficult to reach when on the car. I found it easier to remove the manifold/turbo as an assembly, then separate the two components on the ground. When you separate them, note which way the little lip on the inner edge of the metal gasket faces.

Also note that there's probably a support bracket connecting the bottom of the exhaust manifold to the side of the block. Can be hard to see from above, but you can feel it if you reach between the turbo and the block. Lower bolt should be removed from under the car; it may be helpful to remove the steering damper if you have one. Also, the middle of this bracket may be attached to the air cleaner oil drain tube with a 10 mm nut and bolt that you can't see, but can feel, and can remove with a wrench in each hand.

Expect the intake ports on the engine block to be caked with gunk. It goes without saying that if you clean them, you'll need to be very careful not to let chunks of it (or tools) fall into the block. Wear nitrile gloves.

Good luck.

Paul

Perhaps the part is already available from MB
When we bought a '87 used 300 D Turbo from a dealer here in Canada the cat. was plugged and the dealer replaced it with a plain pipe that sure looked like it was factory. I think that at the time Canadian requirements didn't require a cat.

Might be worth checking into 'cause the fabrication work you are talking about might cost a bit

It would still be faster and cheaper to get federal parts from a junkyard.

No Mercedes junkyards here, unfortunately. Swapping all of the parts needed for a Federal conversion is neither fast nor cheap if you have to buy them from the used parts people and have them shipped.

Our '87 has had the replacement you mention, doxland, but this is an '85 -- different car, different engine.