Pre-Cup Chamber Servicing

[rl71459]

Hi Everyone

I have a question... I hope it is not out of line to post this here, Here goes.

Most here know I run various types of fuel (blended waste Oil) in an old 87' MBZ 190 TD that I have. I drive this car almost everyday. To combat my abuse of this engine I service (Pull, Clean, Reinstall) The Injector's around 4~6 month intervals. as well as early fuel filter changes.

I have never done any major work on any MBZ engine. But I know the "Pre-Cup" Chambers are removable.
What I dont know is can I remove and replace the "Pre-Cups" without removing the head? I can see that the glow plug's will need to be removed first as they pass thru the "Pre-Cup's" and also realize I will need the "Pre-Cup" Splined tool for removal.

The reason I ask is I'm curious if I might see improved performance by cleaning the entire assembly instead of just from the glow plug up.

Rob

[unimog_jason]

I've never worked on the 60x series engines myself but I have pulled the chambers from an OM636 before.

With respect to the OM636 the single most important thing I can start with is make sure you have the right tools, if you don't have the right tools you won't get far and if you do, you'll make a big mess.

You'll have to remove the injector and glowplug first then you'll have to remove the retaining nut that is recessed into the head.  Once you get that out you'll need to take a slide hammer with the correct adapter on the end that threads into the chambers throat and tap it out.  This will likely take quite a bit of effort as there is likely carbon stuffed between the outside of the chamber body and the head.

There is a seal ring you need to replace before you install the chamber and if the retaining nut was damaged in any way you'll likely want to replace it too.

If you don't have the Mercedes manual for this engine that would be the first thing you need to buy as it will have all the details you need inorder to service this engine correctly.  Don't waste your time with the after market manuals, I've never found them to be worth much and lack a lot of details.

Before you go down this path you may want to see if you can buy a small scope that will go into the glow plug hole that will allow you to look around before you take the big step.

Jason

[rl71459]

Thank You Jason

I will get myself a factory service manual. I agree about the aftermarket ones as I already have one of those... Nearly useless.

If you think I'm asking for trouble by removing the "pre-cups" I can continue just servicing the upper
part of the chamber, That's how I have been doing it. I just thought maybe I was not doing a proper job.

It's rewarding to note the difference in starting/running after a cleaning is done. The only cost is the replacement heat shield's and a little labor. It's like a really cheap tune up.

Rob