"Black Death" has reared it's ugly head again. - Page 2 - PeachParts Mercedes-Benz Forum

tjts1 · #16 12-28-2019, 01:41 PM

Quote:

Originally Posted by ROLLGUY

As far as I am concerned, the OM648 is probably the least PITA, and the best passenger car Diesel engine ever made.

And you're entitled to that opinion no matter how wrong it is.

BillGrissom · #17 12-29-2019, 03:07 PM

Hopefully the injectors won't be hard to pull out this pass. Seems the biggest risk is buying a car where it leaked too long and an injector simply can't be removed. All I know is from Rollguy's prior posts. It looks like the main design issue is that they use just a single side bolt to secure each injector, compared to a monster thread in my older OM617 engine. That likely made factory assembly much faster, but not so for the guys who must maintain these. One must use a metal pressure seal, given the pressures and temperatures, so it is critical to apply even loading to get a good seal. Perhaps the single side bolt allows slight cocking in the bore.

chasinthesun · #18 12-30-2019, 12:41 AM

I’ve seen videos where the repair also included a reseating tool for the injector hole , this before the washer placement .I think it’s a very lite resurfacing of the bore landing , when the washer is wasted all that pressure and is on the seat possible slightly wearing on the surface.

engatwork · #19 12-30-2019, 05:42 AM

That is correct, there is a tool used to "clean up" the washer seating surface that is like a small milling bit that you use by hand.

ROLLGUY · #20 12-30-2019, 11:29 AM

I think that is why the same injector seal is leaking. I must not have gotten the seat as clean as I should have. I think I might invest in the tool for resurfacing the seat.......Rich

engatwork · #21 12-30-2019, 12:53 PM

Tool is not very pricey and I suspect should be used anytime an injector is pulled.

ROLLGUY · #22 12-30-2019, 07:02 PM

Quote:

Originally Posted by engatwork

Tool is not very pricey and I suspect should be used anytime an injector is pulled.

Yes, just ordered one....Rich

ROLLGUY · #23 01-11-2020, 05:02 PM

I started the job today. After chipping and vacuuming the tar away, I was able to remove the worst injector with some major slide hammer action. The seal had a spot on it that was definitely leaking. I cut the seat with the tool I just got, and it seemed to work okay. Once the bores and seats were cleaned, the injectors get a coat of ceramic grease. I am having an issue with the bolt bores. It seems that there is some gunk down inside, as three of the bolts seem tight before they contact the clamp. I need to get some carb cleaner down in there to loosen up the grime, and then blow it out with air. The entire job will take about four hours.

engatwork · #24 01-11-2020, 05:08 PM

I'd forgotten about screw holes. They have to be as clean as injector hole.

BillGrissom · #25 01-12-2020, 01:46 AM

Thanks for the excellent photos and info. Not that I'll ever have an E320, but very interesting.

ROLLGUY · #26 01-12-2020, 06:08 PM

Quote:

Originally Posted by BillGrissom

Thanks for the excellent photos and info. Not that I'll ever have an E320, but very interesting.

You should try it, I think you will like it!

ROLLGUY · #27 01-12-2020, 06:16 PM

Quote:

Originally Posted by engatwork

I'd forgotten about screw holes. They have to be as clean as injector hole.

Yes, one of them I had to use a drill bit to get the carbon and other debris out in order to be able to tighten the bolt to 7 NM + 2- 90 degree turns. Before cleaning out the bolt hole, there was about 1/4" gap between the surface of the clamp and the bottom of the bolt (used, not new) head with the bolt as tight as I was willing to tighten it. Working the drill bit, compressed air and PB Blaster got the hole cleaned out enough to allow the new bolt to tighten properly.

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