Re: [MBZ] 1991 350 SDL

[Peter Frederick]

The engineering "world" seems to think the problem was inadequate rod 
strength.  The 3.5L engine used exactly the same rods as the 3.0L 
engine in spite of the higher horsepower and piston weight, and they 
bend in use.  There are some indications that accumulated soot in the 
intake manifold may be a cause, but since a 617 will happily tolerate 
pistons hitting the valves (slip the chain one tooth late...) hard 
enough to make impressions in the piston crowns without immediate 
damage, it's likely the rods weren't strong enough.

They have been re-designed several time, and the latest ones are much 
heavier than the originals.  Only the new ones are available as 
replacements, and you need all 6 -- very expensive.

MB has never admitted a problem.

Peter