Well, after lots of planning and procrastinating, I finally got to work this weekend on my long-awaited 560SEC top-end rebuild. The car has 184K on it, and is blowing a slight amount of blue smoke when pulling away from stoplights -- typical symptom of either bad valve guide seals and/or a loose valve guide. This is allowing oil to drip down into the combustion chamber when the car sits idle, and thus the puff of blue smoke. About 1,000 miles ago, I also started getting a pretty bad ticking from the passenger-side valve-train ... indicative of probably a bad hydraulic compensating element ("lifter") or less likely, a bad rocker arm. I've also had a small (and very common) oil leak from the right rear corner of the head gasket -- an annoyance that drips oil onto the hot exhaust manifold and passes the burned-oil smell into the cabin. This is an extremely common issue with the 560 motors....
In any case, I spent weeks and months scoping out the job and waiting for the weather to get warm enough so that I could work comfortably out in the garage, but still be early enough in the year to avoid the Houston heat and humidity. So it seemed a perfect time to do what I think is going to be about a 5-6 week job. I figure I'll be able to put in little spurts of time in the weeknights with longer periods on the weekends. Also factored in is the machine-shop time to have the heads totally refurbished (valves ground, heads cleaned and pressure tested, checked for cracks, mating surfaces "surfaced", valve springs tested, and new valve guides and seals installed.
I'll also have the intake manifolds (there are two halves on the 560 motor) cleaned and blasted on the inside and outside, and the exhaust manifold will be blasted and then Jet-Hot coated for a nicer appearance. Around the time that this work is being done, I'll order all of the parts from MB that are required to do the proper repairs. I'm being pretty liberal with things, so when I see any part that even looks like it needs replacing, I'll replace it. Of course this massive parts order will also include lots of things like gaskets, all vacuum lines (which will be replaced), rear-engine heater hose (may as well do it as it's accessible now), and so forth.
Working this weekend, I got as far as getting the intake manifold off and the exhaust manifolds partially off. The intake manifold had tons of carbon in it but the heads were shocking -- lots of caked-on carbon that was partially blocking the passages! You can see it in a picture. It will be interesting to see the exhaust ports when I get the exhaust manifolds off; I am wondering how much carbon blockage is in the exhaust ports, as well as wondering which valve guide/seal combo is letting oil into the chamber. I'll find out soon enough.
This is a pretty involved job and as I'm getting into it, I've found LOTS of brittle rubber and vacuum lines, plastic connectors and other little bits that I'm planning on replacing with MB parts. It just goes to show how much of a toll that heat and age take on rubber and soft bits. The 560SEC engine compartment is much larger than the E500Es, so it's much easier for air to circulate around in there and I think this probably preserves the rubber and soft parts better than the oven that is the engine compartment of our E500Es.
In any case, I hope you enjoy this thread and I'll keep it updated regularly with photos as the project progresses. I hope to have the exhaust manifolds and the heads disassembled (cams, rocker arms and lifters removed) this week. I'll plan to bring the heads into the machine shop for renewal in the next couple of weeks.
In the meantime, while things are at the shop getting worked over, I'll clean the valley in the middle of the engine, clean all of the gunk off of the throttle body, and prepare my final order list of parts.
The scary thing will be putting everything back together! I hope I can remember how it all goes back....