Greg,

I resisted digging the manual out and reading the procedure just because it was busy here, what with Santa visiting and a daughter with a 1982 240D needing a blower motor repair, new lights in the dash and the heater control knobs, and the instrument panel rheostat removed and shorted out. But I can see you need a little support here.

Per the manual, to get a real reading you check valve timing or chain "elongation" (glad we got that right), by setting the number one cylinder intake valve cam in the vertical position, shimming the gap closed, all of which typically takes place after setting the clearances. Then you attach a dial indicator to the head in appropriate locations noted in the manual, so you can put the tip of the indicator on the spring retainer of the number one intake valve. Zero the indicator at a 3mm preload, and then rotate the engine in the normal direction with a tool connected to the front of the crankshaft until the dial indicator shows the valve has openned 2 mm. IN this position read the value at the balancing disc.

The manual does recognize the alignment mark method, which is used for engine assembly with new parts, but suggests any check for performance related questions should be per the above instructions.

I am always amazed at the fact that in next paragraph the manual says to correct the chain "elongation" effects by inserting an offset woodruff key and this method is never used . Or even mentioned when people talk about addressing a fix for chain "elongation." It seems the discussion of changing pitch of the chain links noted above would say the MB engineers and mechanics that use offset woodruff keys are in the dark about this subject. I think in reality the sprockets wear as fast or faster than the links, as they see more engagements and disengagements per hour of operation than each link of the chain does. The chain spreads the wear over the whole length, while the sprocket hits the same places on each tooth over and over. A new chain does not address this issue either.

AS usual there is no single response. I hope this helps. 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)