Dan,

Having done this a number of times now, the procedure is not that difficult. The scariest part for me is loosening the sprocket connection to the camshaft and worrying about dropping a screw into the chain box or getting one of the screws jammed against the head (lots of "features" in the area the head of the bolt can get caught on while you turn the engine over and then bend the fastener - I know from personal experience, and the fastener is a pretty common metric size, including length so it will be available locally on a Sunday, if you know what I mean). The exhaust side is particularly tricky. Do the job in good light so you can see what you are doing clearly.

You need a micrometer to measure the existing shim if the original thickness value has been blurred or worn from friction. The first time I did this I checked them all to make sure the etched values and measured values were the same. They were and now I only measure the ones I cannot read clearly.

I also made up a record sheet to enter measured clearance between the camshaft and the tappet/bucket for each valve, and a formula that, once I enter the known shim size, calculates the final shim size. Unfortunately not all the 19 cited sizes are always available. The range of clearances can be accomodated though, and I aim for the high end of the tolerance (largest allowable clearance) if the shim I need for the middle value is not available. I record the shim thickness of the new shims for each valve and then reassemble.

The camshaft to sprocket flanged connection has four bolts and the holes are not symmetrical so the joint only goes together one way. I usually take a digital shot of the area for memory help to avoid cranking it over a bunch with the flats provided for that purpose on the camshaft.

I liberally coat the camshaft, camshaft supports, tappets and camshaft support caps with oil (Delvac 1) upon reassembly. The sequence of bolting the camshaft bearing caps down (or taking them off) depends somewhat on the position of the camshaft when you begin the camshaft bearing cap disassembly. I suppose you can try to control the camshaft position but I have not since I typically do both camshafts (take one off at a time, then put one back on at a time) in one event to minimize the waiting time for the shims. Anyway, I loosen the cam bearing cap fasteners slightly on all bearing positions in a sequence to minimize the bowing of the camshaft. It is visually apparent when you are doing this, and if you take your time the sequence works out kind of by itself. The same at reassembly - I bring the cap fasteners (nuts as I recall) down snug by hand,which is not really much force, then move around on the ones that are closer to the valves being opened as the camshaft is drawn down into position, and continue tightening the easier ones by hand. Once the caps are all seated, I use the torque wrench and go from the inside (middle) to the ends a couple times to make sure everything is ok. Then I turn the camshaft by hand with a cresent wrench (big one) on the camshaft flats and check the bearing cap torque between every set of valve actuation positions.

I then line up the sprockets and the sprocket to camshaft connections and make up that joint. You have to turn the camshaft with the engine to access to the bolts/bolt holes on disassembly and reassembly. At least I do.

The rest is straightforward. Remember to be very careful to keep things very clean. I have used nothing but synthetic motor oil on my car, or my son's car now, and as of the last few years, nothing but Mobil Delvac 1. The inside of the engine is very visually clean, and when you take things apart it is amazing how clean it actually is. Dirt (typical junk inside the engine compartment, like sand, hood pad debris, grease with road dirt and so on) needs to be kept out when the engine is open. I typically use a clean shop towel to cover everything while I wait for the shims, or go to the hardware store for a fastener, etc.

By recording the shim dimensions in each valve location the next time you can order the replacements upon measuring the clearance, or, if swapping ones you have will work. I never throw shims out. Good luck, Jim

__________________
Own:
1986 Euro 190E 2.3-16 (291,000 miles),
1998 E300D TurboDiesel, 231,000 miles -purchased with 45,000,
1988 300E 5-speed 252,000 miles,
1983 240D 4-speed, purchased w/136,000, now with 222,000 miles.
2009 ML320CDI Bluetec, 89,000 miles

Owned:
1971 220D (250,000 miles plus, sold to father-in-law),
1975 240D (245,000 miles - died of body rot),
1991 350SD (176,560 miles, weakest Benz I have owned),
1999 C230 Sport (45,400 miles),
1982 240D (321,000 miles, put to sleep)