Lower rails do break
'89 560 SEL, 110,000 miles. Box of parts to do upper rails and chain in the garage for a year. Scared to try. Rough idle, heavy oil consumption which I thought was due valve seals fouling plugs, parts in the same box in the garage. Two months ago, she kicked and died shortly after starting one morning. Chased fuel issues for a time, then Craig Morris (AFMCorp, regular poster here) pointed me to timing. Pulled right valve cover, aligned cam marks and determined 14 degrees of stretch. Gathered the courage....
Since the right cover was off, did the upper rail there, really smooth job. Pulled the left cover and immediately saw rail fragments all over the place. Both upper rails gone. Cam nearly 90 degrees late at 1 TDC. Spent Saturday fishing rail pieces and beginning tear-down for probable removal of timing cover. Removed lower oil pan and was able to piece together most of the two upper rails, but had a large chunk that didn't seem to belong--darker, less brittle. Started checking broken pieces for part numbers, and found 3 different numbers. Checked Fastlane, and the third number was from the LOWER LEFT rail. Definitely have to pull the timing cover now. Ran out of steam at the crank bolt last night, and no time to work today. Seems to be one tight bolt.
Now for some questions.....
When the new chain is eventually rolled in, should the cam marks on both sides line up when she's at #1 TDC?
Is the purpose for loosening the upper oil pan (3 to 4 turns per bolt according to alldata) just to allow the cover to clear the bottom of the head?
Engine just gave one backfire and died, no cataclysmic metallic banging when she went. Has turned without interference since. Any chance that no valves were damaged??
Anyone want to came and remove that blasted crank bolt??
Am I crazy to try to make her run again? Should she become a donor?
Thanks for listening.
'02 C230 Kompressor
'89 560 SEL "Frau BlueCar" (retired April 2004)