Nothing looks bad from my experiences at rebuilding these engines. Now that you have it apart

First take a die grinder with a steel tip and deburr the exhaust ports. Reduces hot spots and improves exhaust flow.

Second give the head a valve job, now that you have disasembled the engine. Cylinder head exchange in Ft Lauderdale Florida does all of our diesel heads and they replace the prechambers. They always praise our exhaust port work. They gave us the idea.

Third replace the timing chain and guides while you have it apart.

Reassemble and go.

Your earlier comments Cylinder 2 & 5 indicate valves not piston rings. This is based on 20 years of experience with these long blocks.

Thanks guys! Good to see your fingers aren't so frozen that you can't type. Or perhaps the whole family is gathered around the monitor to keep warm? :p

Okay, a few comments based on what you all have said...

The carbon build up on valve one and two is uneven, and white edges, whereas the others are just evenly coated. Any significance?

In pic 5, it looks like there might have been a leak around the bolt? It shows up better on the valves pic. The head gasket looks intact.

Yes, we did discuss getting pics with the pistons all up, but the timing chain is stuck at the moment so there's not too much movement. It would have taken too long to resolve adn the camera was burning a hole in my hand.

Valve 3 is the one leaking, but it also had the highest compression. Could be multiple problems going on I suppose.

A valve adjustment was done while it was still in the car, and it didn't have a noticeable improvement (still very rough idle). However, upon dismantling of hte car hubby discovered the EGR valve was completely stuck. I think he had to use a vice to get it to move (interesting you mention the EGR valve Randy). So, maybe there were multiple problems going on.

Tony, your comments so very encouraging!

I'll keep you posted once we get some measurements.

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Natalie

If an engine ran OK I would hesitate to tear into it especially an engine as expensive to rebuild as a MB diesel.
A few years ago my '85 300D had a compression check done on it when it had 173K miles on it by the previous owner. The readings were 380,380,380,340 and 295. The injectors were checked out then and they were OK. A valve adjustment was done about 3K miles later. The last two numbers kind of worry me but the car seems to still run fine with 222K on it now. I haven't done a compression check since that last one but I don't have a diesel compression check gauge nor do I want to have to pull the glow plugs to do it since it is a BIG PIA to pull them. Do the last two numbers indicate a problem? If this were a gasser and had two comparatively low numbers in neighboring cylinders I would be convinced that there is a problem.

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DJ


84 300D Turbodiesel 190K with 4 speed manual sold in 03/2012