Engine Out!!!!
 

I finally got the engine out of my 92 300TE 4-matic "twin turbo" this evening. I was fortunate enough to have a couple co-workers rig up a chain to support the front of the transmission while I broke everything else apart underneath. I got it out, bolted it to my engine stand and called it a night. I'm anxious to get a peek inside the block to see if the piston oiling machine work has been done on the 4-matic blocks. With few appointments for tomorrow I might have time to get the oil pan off. I can hardly wait. :sun_smile

Good stuff. But what is your project/goal?

I plan to bore the block oversize and install lower compression pistons. Along the way I want to machine the block to accept the diesel engine piston oil sprayers as well as modify the oil pump drive and possibly the pump. If I can locate a diesel crankshaft on the cheap I might swap for more displacement. So far no luck. I'm thinking about thermal barrier coating the piston crowns and moly coating the skirts so that this shortblock can take whatever I throw at it. After that it will just be a matter of how much fuel I can deliver and what the driveline will take. :sun_smile

Sounds like a serious project!

I plan to (try and) put some new engine mounts in my SE this month...I'm not much of a mechanic, but I try.

Good luck.

Update
 

I tore down the engine today. The pistons were toast. In the areas where the detonation was occuring the upper ring was pounding so hard on the land that it displaced the lower land binding the 2nd ring in it's groove. The bores looked good with only minor scoring which could only be seen but not felt, otherwise it was still showing it's crosshatch. Not bad for a 200K mi turbo'd 103. The main bearings were all in very good shape. A few of the rod bearings were starting to go through the first few layers of the bearing. There doesn't appear to be any damage to the crankshaft journals. Now for the good news.... the 4-matic block (103.985) does have the machine work for the piston oilers. Once I was down to a bare block I tossed it into our industrial parts washer. After drying everything out I went ahead and tapped the 6 bolt holes that mount the piston oilers. On the fourth one the 6x1.00 tap broke off in the block. It took about an hour to fight the broken tap out. After I had all the threads cut I went ahead and drilled the 4mm feed holes into the main oil galley. I rigged up an adaptor to put air pressure on the galley to keep as much of the chips out as possible. Minus the broken tap it's not an hour of work to finish the machine work to install the oilers (on a bare block that is). I really believe that the oilers are key to preventing a reoccurance of piston related problems. I'm really happy to know that I can do it with factory parts. :sun_smile

So the 103 motor in a 4 matic car has different internals than the one in other models?

The block is slightly different. The differences have to do with having a differential in the oil pan. In the middle of the block there are several oil pan bolts than go in through the top b/c the diff. precludes being able to go in through the bottom. All of the major components, crank, rods, pistons, cylinder head, ect are the same. The block, oil pump, and of course the oil pan and it's associated hardware are the only engine parts I'm aware of that are different.

Sounds like you really know your stuff. Are you a professional?

Yes I am. I work for the BEST independant Mercedes repair shop in Denver, Star Tech. I'm in my eighth year of Mercedes specific repairs. Funny it took me 8 years to buy one, but it's hard to pass up a twin turbo 4-matic no matter what's wrong with it.

wow the front diff is inside the engine oil pan? Odd, not a bad idea, but odd... I don't believe I have seen that in any other car.

Twin turbo?

Mosselman :sun_smile

Dux,

We'd love to see photos of your turbo beastie! :D

Side question: I just pulled the OM603 out of my 300D to replace the timing cover, and do some other assorted maintenance. I was going to bolt it up to my Harbor Freight engine stand, but then I noticed the bellhousing bolts are awfully small... M10! Is it safe to hang all the weight of a complete 603 from four M10 bolts? The last thing I need is to break off the back of the block or something...! :eek: :eek: Am I just being paranoid?


Best regards,

gsxr - remove the bell housing and flywheel. Bolt the engine stand up to the block itself.

Jim, I removed the tranny and intend to bolt up to the block itself. Just nervous about the small-ish bolts holding allll that weight. Lots of leverage out in front of the engine. I'm probably just being paranoid...

:o :o