Date registered: Aug 2010
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250 SL Engine Vacuum Specs.
Right at 15" Hg..... and very stable reading.
No complaints at all on how the car runs; smooth idle; smooth and strong acceleration ro redline; no backfire on decel; 123 electronic distributor; running 5 Deg. BTDC (vac. line connected) at 800 rpm idle speed. New MB block with about 70,000 miles; head job done within the last 3,000 miles.
The big blue MB Service Manual (page 00-0/21) seems to suggest that 300-400 mm Hg (11.8-15.7 in. Hg) is the acceptable range, but I'm not sure I'm reading that table correctly.
I'm just accustomed to seeing 18-20 in. Hg vacuum on American cars, and was surprised at my low reading on the 250 SL. But....it does have vacuum "retard" at idle.
I would just like confirmation on what MB says the idle vacuum should be. If it, in fact, should be in the 18-20 in. Hg range, I will do a serious investigation as to cause.
Thanks again.... and appreciate the inquiry.
Euro with 5-speed