BenzWorld Junior Member
Date registered: Mar 2008
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94 e420 m119 ate a timing chain
Ok, so our 1994 e420 broke a timing chain the other day. It stopped the motor rather quickly, although I wasn't driving, so I can't describe the exact event. No noisy prelude or after party...it just stopped running.
It was towed to a garage, and they've noted that the crank will only move a few degrees in each direction, so the chain is firmly wedged in there somewhere. The car has 172K on it, and was otherwise very happy (except for occasional and unrelated surging idle issues). It's always been serviced regularly, but I now see, poking around, that there's some preventative maintenance in this area that might have been wise.
Anyway, cutting to the chase, what do you all think is the wisest course of action from here? Should we buy a salvage motor and drop it in, or repair this one? This one is obviously a known quantity, with no issues of oil consumption or anything. Assuming the chain didn't manage to do any really deep damage, it should be a matter of extracting the broken one, putting on new guides and tensioner and chain (and obviously inspecting the cam and crank sprockets for damage (likely some, somewhere)). It's a lot of labor and a fair number of expensive parts -- I can't imagine escaping for less than $3K or so.
The other option is to drop in a salvage motor. This doesn't look especially cheap, either. How many hours of work is a transplant? How much should I figure to spend, and how do I know I'm getting a good one? The car has a recently-replaced wiring harness and, like I said, is otherwise very clean and functional. California car, so there's no decay or other factors that would suggest retirement.
Thanks. These motors have such a reputation for immotality that I'm tempted to say we should fix this one, unless you all think that further damage from the incident is going to reveal itself after the direct cause is fixed (e.g., bent crank or rods). If I do go with a replacement, what range of options is a direct drop-in? Any issues with one from an earlier e400, if one looks good? We're satisfied with the current performance, but what are the other displacement options on the replacement?
So, repair or replace, on the motor?