1980 300SD turbo pics - trouble? - PeachParts Mercedes-Benz Forum

djburt · #1 09-15-2012, 09:47 AM

While getting in to clean up a nasty oil spill from the other day (don't ask), I noticed two things on my turbo. 1) the chip on the metal part where the hose clamps on is bigger than I thought, and 2) The fan blades on the turbine in there seem to be quite worn down.

Does this look beyond repair? I haven't taken the turbo unit apart yet, I understand there can be significant carbon build up in there. I do have a lack of power especially at low speeds, which I'm in the process of ruling out. Bottom line: I don't know how much my turbo is really contributing at the moment.

Next steps?

sixto · #2 09-15-2012, 01:28 PM

That's the compressor wheel. The turbine wheel is on the exhaust end. Either way, the wheel should spin smoothly with only a hair's width of radial play and absolutely no axial play.

Do a search on cleaning the banjo bolt to see if you're 10 minutes (and a serious engine cleaning) away from finding the lost power.

Someone wasn't kind to that turbo to chip away the lip from the air intake flange. I expect the vanes would be in far worse shape if any chips were ingested. Not to mention the chips would be in the combustion chambers by now.

Sixto
87 300D

djburt · #3 09-16-2012, 04:16 PM

Already checked the banjo bolt - and the line running to the ALDA. I'd hoped it would be terribly dirty and clogged, but it wasn't the culprit.

I think there's more than a hair's length of radial play (that's side to side, right, like along the radius?). Should I consider taking the unit apart and checking for any worn bearings or anything?

sixto · #4 09-16-2012, 05:00 PM

Remove the ALDA and see if that restores the power you expect from the engine. Don't just disconnect it, remove it. There's a nut on the IP that takes a 24mm wrench. The ALDA has flats that take a 27mm wrench just above the nut or you can use the flat edges of the main ALDA body to hold it while loosening the nut. It's not necessary to cap the IP fitting. Even if you see oil in the cavity, it won't leak oil with the ALDA off. An option is to throw a couple of oil drain plug washers between the IP and ALDA so you can keep the ALDA in place for looks and not to lose it in the garage yet not have it hold back the fun.

I suppose you can take the turbo apart but I don't know what to look for in terms of wear. Make sure you have the right rebuild kit for it before you take it apart. If the shaft turns smoothly and it's not dumping oil into the compressor or turbine housings, I'd hold off touching it until you confirm what's wrong with the engine.

Sixto
87 300D

Diesel911 · #5 09-16-2012, 10:48 PM

When pieces of the Compressor Wheel are gone it is out of Balance; see the pic.

Mark the position of and carefully remove the Turbo charger Compressor Housing to inspect the Compressor Wheel better.

The shaft in and out play is supposed to be 0.001-0.004". If the end play exceeds 0.004" the Thrust collar and Bearing have issues.

As the Trusnt Bearing and Collar Wear the Compressor Wheel gets closer to the Compressor Housing in the outward direction of the Shaft. As the Bearings and Bearing Housing wears the outer diameter of both Turbine and Comperssor Weels gets closer to to the Turbo Housings.

If the Compressor wheel has worn into the Compressor Housing and there is a lot of chips on the Wheel the cheapest solution is to try to get another used Turbo and reseal that one.

In th pic I circled the worst area I can see but it looks like all of the Tips of the Fins have a little damage like it has been dragging on the tips a little.

eatont9999 · #6 09-17-2012, 10:07 PM

Holy crap, DJ! That turbo has seen some pretty nasty neglect. That is probably the worst looking one I have seen on a 300SD. The compressor blades have definitely seen some foreign material and the wear on the compressor housing leads me to believe that someone did not have the air pan elbow attached properly for quite a long time. If that were my turbo, I would be replacing it with one from a junk yard that is in good condition. I'm not sure that it is causing your performance issues but I am sure it is not helping and more importantly, it is a ticking time bomb on your engine. The last thing you want is for the compressor wheel to smack the housing, break off and be ingested into the engine at 60MPH! Last weekend I picked up a turbo from a 1982 300SD that someone was so generous enough to pull it and leave it on the back seat for $80. I'm not sure why or what the person was looking for but once I found all the pieces for the turbo, I took it home. I plan on rebuilding it like I did my Banks Sidewinder a few months back. Not hard to do. I'll be making and posting complete A-Z instructional videos once I get started.

Good luck.